AP Environmental Science Course Review Part 3
AP Environmental Science Course Review Part 3
6.2 Global Energy Consumption
The use of energy resources is not evenly distributed between developed and developing countries
The most widely used sources of energy are fossil fuels
As developing countries become more developed, their reliance on fossil fuels for energy increases
Developed vs Developing Countries
Developed nations use more energy on a per capita basis but developing nations use more energy in total (higher pop)
Developing nations are still industrializing & pop is still growing rapidly
Also increase on per/person as countries industrialize + residents achieve higher standards of living
Fossil fuels
Most common fuel source globally
oil>gasoline=main fuel for vehicles
coal=main fuel for electricity
Natural gas=secondary fuel for electricity and main fuel for heating
Hydroelectric energy (dams used to create electricity) are 2nd largest source of energy
Water spins a turbine which generates electricity
nuclear energy is the 3rd largest source
Uranium fission releases heat to turn water into steam to turn a turbine >generate electricity
Development increases Fossil Fuel Consumption
Many residents of less developed countries depend on subsistence fuels (biomass that can be easily gathered/purchased and used)
Wood, charcoal, dried animal manure (can drive deforestation)
Economic development>wealth>higher per capita GDP>energy use
As developing nations develop, fossil fuel consumption increases
Factors that affect energy source
Predominant energy source until 1875: wood>coal>1950s: nuclear>oil, natural gas, coal
Availability: what fuels can consumers get?
Price: supply and demand
Governmental regulation: what fuels can consumers get?
6.3 Fuel Types and Uses
Subsistence fuels
Biomass fuel sources that are easily accessible; often used in developing countries as a home heating or cooking fuel
Wood (and charcoal) are the most common fuel sources in developing nations
Wood is free/cheap to cut down and utilize as fuel, can cause deforestation and habitat loss
Charcoal is made by heating wood under low O2 conditions for long time
Peat is partially decomposed organic matter (usually ferns or other plants) found in wet, aidic ecosystems like bogs and moors
Can be dried and used as a biomass fuel source
Coal formation
peat>lignite>bituminous>anthracite
Pressure from overlying and sediment layers compacts peat into coal over time
Depper a coal reserve is buried, the more pressure from overlying rock layer>more energy dense
Anthracite is the most valuable form of coal
Coal is burned to heat water into steam, to turn a turbine that generates electricity
Peat (not a coal: partially decayed plant matter in swamps/bphs
Lignite (brown coal): low heat content, low sulfur content, limited supplies in most areas
Bituminous coal (soft coal: extensively used as fuel b/c of high heat content, high heat content
Anthracite: best quality, high heating capacity, lowest sulfur content (CLEANEST)
Mining Basics
Ore: commercially valuable deposits of concentrated minerals that can be harvested and used as raw materials
Metals: elements that conduct electricity, heat, and have structura properties for building ( found within ores)
Reserve: known amount of a resource left that can be mined
Usually measured in years left of mining
Overburden: soil, vegetation, rocks that are removed to get to an ore deposit below
Tailings & Slag: leftover waste material separated from the valuable metal or mineral within ore (often stored in ponds @ mine site) MESS
Surface Mining
Removal of overburdened to access ore near surface
Different types of surface mining: Open pit, Strip mining, placer, mountaintop removal
Mountaintop removal: esp damaging to landscape and habitats, streams nearby
Removal of vegetation/ soil= topsoil erosion, habitat loss, increased stream turb, increased PM (particulate matter) in air
Strip mining: removal of strips of soil/rock to expose ore
Remove material, extract resource, return mining spoils/tailings
Coal, sand
Open-pit mining: uses a large visible pit/hole
Resource close to surface
copper
Mountaintop removal: with explosives
Tailings deposited in nearby regions
Placer mining: looking for minerals and metals in river sediments
Diamonds, tantalum, gold (CA gold rush)
Subsurface Mining
More expensive due to high rinsurance/health care costs for workers
Risks: poor ventilation>toxic gas exposure, mine shaft collapse, injury from falling rock, lung cancer, asbestos, fires, explosions
Vertical “shaft” drilled down into ground
Elevator to carry down workers & transport out resource
Often used for coal
Increased used as surface coal deposits are depleted
Environmental Impacts of Mining
Contamination of surface and groundwater with acidic mine drainage
Habitat destruction
Release of dust and harmful gases such as methane and H2S
Rainwater carries sulfuric acid into nearby streams, infiltrates ground water
Lowers pH of water, making toxic metals like mercury/aluminum more soluble in water source (kills aquatic organisms)
Methane release: coal mining releases methane gas (CH4) from rocks around coal
Vented out of mine to prevent explosion and continues seeping out after mine closes
GHG>>>CLIMATE CHANGE
PM (particulate matter) release: coal mining especially releases lots of soot and other particulates that can irritate human and animal lungs
Mine Reclamation
Process of restoring land to original state after mining has finished
Includes
Filling of empty mine shaft/hole
Restoring original contours of land
Returning topsoil with acids, metals, and tailings removed
Replanting of native plants to restore community to as close to original state as possible
Mining Legislation
Mining law of 1872 (general mining act):
Allows individuals and companies to recover ores and fuels from federal lands
Few provisions for environmental protection
Surface mining control and reclamation act (1977):
Land must be minimally distributed during coal mining and then reclaimed
Related legislation: clean air act, clean water act, superfund act
Natural Gas
Decaying remains of plants and animals (mostly marine life) are buried under layers of rock and converted by pressure into oil (petroleum) and natural gas over time
Natural gas is mostly methane (CH4) and is found on top of trapped oil (petroleum) deposits
Forms when oil is trapped in a porous, sedimentary rock underneath a harder, impermeable rock layer that doesnt let the gas escape
Considered the cleanest fossil fuel (produces the fewest air pollutants and least CO2 when burned)
Produces about 1/2 as much CO2 as coal when burned to generate electricity
Produces virtually no PM (ash/soot)
Produces less SO4, NO2 than coal/oil and no mercury
Crude Oil (petroleum)
Decaying organic matter trapped under rock layers is compressed into oil over time
Extracted by drilling a well through the overlying rock layers to reach the underground deposit and then pumping liquid oil out under pressure
Can also be received from tar sands (combination of clay, sand, water, and bitumen)
Bitumen is a thick, sticky, semi-solid form of petroleum (not liquid)
Extracting & using oil from tar sand is extremely energy and water intensive
Lots of water needs to be heated (requiring energy) to create steam thats piped down into the tar sand to melt the bitumen into a liquid that can flow up a pipe
Lots more water is used to separate the oil from all of the impurities (sand, clay) at the refinery
6.4 Distribution of Natural Energy Resources
Fossil Fuel Products
Crude oil (petroleum) is converted into lots of different products through the process of fractional distillation
Crude oil is burned in a furnace and water vapor passes into a column where different hydrocarbons are separated based on their boiling points
hydrocarbons w/ lower boiling points gather at the top of the column, higher boiling points gather at bottom
Different hydrocarbons within petroleum are used for different products
Petroleum gas (PUMPING OF VISCOUS LIQUID)
Gasoline (fuel for cars)
Naphtha (used to make plastic)
Jet fuel
Diesel fuel
Motor oil
Bitumen (asphalt for roads)
FF Energy Reserved
Coal (100-150 years left)
US, Russia, China, Australia
Natural Gas (50-60 years left)
Russia, iran, qatar, US, saudi Arabia
Oil (50ish years left)
Venezuela, saudi arabia, iran, canada, iraq
Fracking and Shale Gas
Hydraulic fracturing (aka fracking) is method of natural gas extraction that has extended access to natural gas
Gas trapped in semi-permeable sedimentary rock layers like shale is released by cracking the rock with pressurized water
Well is made; pipe is inserted; fracking fluid is inserted; gas flows out
Fracking natural gas from shale rock increases/extended supply of natural gas
Can contaminate water/destroy habitat; pipe is not lined properly, may contaminate water; fracking fluid has volatile organic compounds (VOCs); Leads to earthquakes from breaking rock and destabilizing the ground from the pressure
Shale Gas Reserves
FF are non-renewable and will eventually be depleted, but short-term economic profit still drives extraction and use
Discovered but unharvested reserves rep economic benefit to countries
Tar/Oil Sands
Bitumen deposits where crude oil can be recovered but with higher water & energy inputs
Canada: alberta region = world’s largest oil sands reserve
tar/oil islands extraction extends the world’s supply of crude oil
6.5 Fossil Fuels
Fossil Fuel Combustion
Reaction between O2 and fossil fuels releases energy as heat and produced CO2 and H2O as products
Combustion is step in carbon cycle (Hydrocarbons -FFs- are burned to release energy and the carbon stored in them reacts w O2 in the air to form CO2
Methane (natural gas), gasoline, propane, butane, coal are fossil fuels (hydrocarbons) that release energy in the same way
wood/biomass work same
FF to Generate Electricity
The #1 source of electricity production globally is coal, then natural gas
Heat> water into steam> steam turns a turbine, turbine powers generator> generator produces electricity
Coal, oil, natural gas, biomass, and trash acn all be burned to drive this same process and create energy
Nuclear energy works similarly, nuclear fission prodicing inital heat
Environmental Consequences>COAL
Habitat destruction to clear land for mining
Produces pollutants and relases CO@ (GHG> global warming)
Releases more CO2 than other FF when burned for electricity
Release PM (soot, ash) which can irritate respiratory system
Produces toxic ash contaminated w lead, mercury, and arsenic
Taken to landfills, stored in ash ponds which can leak into ground/surface water or into soil
Releases sulfur and nitrogen oxides which irritate resp systems and contribute to smog and acid precipitation
Generating Electricity
Coal is 30% efficient for generating electricity
Nat. gas is 60% efficient
Much of energy “lost” or not converted into electricity escapes as heat
Cogeneration: when heat produced from electricity generation is used to provide heat (air and hot water) to a building
CHP (combined heat and power) systems are close to 90% efficient
Environmental consequences: tar sands
Habitat destruction to clear land (biodiv loss)
Ground or nearby surface water depletion (H20) needed for steam and washing impurities from bitumen at refinery
Water contamination: tailing ponds can overflow and run into nearby surface waters or leach into groundwater
Carcinogen salts, acids, hydrocarbons, bitumens all toxic to plants/animals
CO2 released b machinery during extraction, transport, refinement
Environmental consequences: crude oil/petroleum
Possibility of spill (from tanker ships or pipeline)
Spills in water= crude oil covering sun, clogging fish gills, suffocating ocean animals, sticking to bird feather
Spills on land= toxic to plant roots, surface, or groundwater contamination
Habitat or fragmentation when land is cleared for roads, drilling equipment, pipelines
Fracking (Hydraulic Fracturing)
Used to extract natural gas from sedimentary rock
Vertical well is drilled down
How is energy produced in a coal-fired power plant
Coal is burned, creates steam through the boiling water, steam turns turbine, turbine turns generator, generator creates electricity
One environmental issue that can arise from combustion of fossil fuels
Mining for resources, pulverized coal, water use, carbon dioxide production
6.6 Nuclear Energy
Nuclear fission and radioactivity
A neutron is fired into the nucleus of a radioactive (unstable) element, such as uranium
Nucleus breaks apart and releases lost of energy (heat) and more neutrons that break more nuclei, releasing more energy (chain reaction)
Radioactivity refers to the energy given off by a nucleus of a radioactive isotope (uranium-235)
Radioactive nuclei decay or breakdown and give off energy (radiation) without fission, nuclear fission releases tons of energy all at once
Radioactive half life= amount of time it takes for 50% of a radioactive substance to decay (breakdown)
10 half-lives generally means saftey
Cobalt-60 takes 5.37 yrs to undergo half life
20 g is the 100% and undergoes half-life (5.27 years)= 10 g left (50%)
Half life #2 is 5g (25%)
Generating electricity
heat> water into steam>steam turns a turbine>turbine powers generator>generator produces electricity
U-235 stored in fuel rods, submerged in water in reaction core, heat from fission turns H20>steam> turns turbine>powers generator> makes electricity
Control rods are lowered into reactor core to absorb neutrons and slow down reaction, preventing meltdown/explosion
Water pump brings in cool water to be turned into steam and cools reactor from overheating
Nonrenewable, but cleaner than FF
Is nonrenewable b/c radioactive elements like uranium is limited
No air pollutants or CO2/CH4 released when electricity is generated, mining of uranium, plant construction stil release GHG
Only gases released from elec gen is water vapor (technically GHG but stays in atm briefly)
Spent fuel rods: used fuel rods remain radioactive for millions of years and need to be stored in lead containers on site @ nuclear PP
Mine tailing: leftover rock and soil from mining have radioactive elements to contaminate soil/water nearby
Water use: nuclear PP require lots of water and can deplete surface/groundwater sources
Thermal pollution: hot water from PP released back into surface water can cause thermal shock (decreased O2 and suffocation)
Nuclear meltdowns
Three Mile island (US): partial meltdown due to testing error, radiation released but no deaths/cancer
Fukushima (japan): earthquake and tsunami triggered cooling pump failure that led to meltdown (explosion of reactor core) and widespread radiation release
Chernobyl (ukraine): stuck cooling valve during test elad to complete meltdowns, several deaths + widespread radiation release
Contaminated soil: radiation can remain in soil and harm plants and animals in the future
Radiation spread: radiation can be carried by the wind over long distances
6.7 Energy from Biomass
Biomass vs. Biofuels
Biomass: organic matter (wood/charcoal, dried animal waste, dead leaves/brush) burned to release heat- mostly for heating gomes/cooking
Utilized primarily in developing world for heating homes/cooking
Easy to harvest, available, cheap/free (subsistence fuel)
Can be burned in PP to generate electricity(less common than FFs)
Biofuels: liquid fuels (ethanol, biodiesel)
Used as replacement fuel sources for gasoline, primarily in vehicles
Modern vs fossil carbon
Biomass burning CO2 but does not increase atmospheric CO2 levels like FF burning
Burning biomass releases modern carbon (CO2 that was recently taken out of the atmosphere); FF burning releases fossil carbon that has been stored for millions of years
Biomass burning considered carbon neutral
Humanhealth and env consequences of biomass burning
Releases CO, NO3, PM, VOCs-volatile organic compounds-(respiratory irritants)
3 billion people globally cook an open biomass fires (developing world)
Biomass bruns indor worsens asthma, bronchitis, COPD, emphysema
Environmental consequences=deforestation and air pollutants
Biofuels: ethanol and algae
Corn and sugarcane are fermented into ethanol which is mixed w gasoline
Corn grain/sugar cane broken down and yeast ferments sugar>ethanol
E85 or flex fuel= 51-83% ethanol + gasoline mix
Decreases oil consumption for transportation, but is less efficient than pure gasoline
“Renewable” only to extent of production of corn is sustainable (sugar cane is a perennial= more sustainable)
Environmental consequences= all the neg. consequences of monocrop org
Soil erosion, hab. Loss, GHG release (soils, tractors, fertilizers), H2O use
Lots of corn needed, relative to petroleum, can compete w human consumption of corn
Algae produce oils that can be used as biofuels more sustainably than corn
Biodiesel
Liquid fuels produced specifically from plant oils (soy, canola, palm)
Palm oil biodiesel has been found to produce 98% more GHG than FF from clearing of forests for palm plantations
One resource that can be combusted to provide heat and describe a neg consequence that results
Wood can be combusted to provide heat that results in deforestation depending on the location
Describe a potential solution to the negative consequence to part a
Government regulation or efforts to regulate forest growth
One source of biofuel that causes loss of habitat and solution to produce biofuels with decreased habitat impact
Brazil forests or in gee, solution cou
6.8 Solar Energy
Active vs Passive solar energy
Passive: absorbing or blocking heat from the sun w/o use of mechanical electrical equip
Using sun’s heat to cook food in a solar oven
Orienting building design to block sunlight in warmer months and allow sunlight in during colder months
Active: use of mechanical/electrical equip to capture sun’s heat (solar water heaters or CST- concentrated solar thermal) or convert light rays directly into electricity (PV cells)
Solar water heaters capture suns heat in water or circulating fluid and transfer heat to warm water for home
Photovoltaic Cells
Aka solar panels; contain semiconductor (usually silicon) that emits low voltage electrical current when exposed to sun
Photons (particles carrying energy from sun) cause separation of charges between 2 semiconductors layers, electrons sep from protons and flow through circuit to load, delivering energy as electricity
Drawback: intermittency (solar energy can only be generated during the say)
Could be solved by cheaper, larger batteries that can store energy generated during teh day for use at night (not currently available)
Concentrated Solar Thermal (CST)
Heliostats (mirrors) reflects sun’s rays onto a central water tower to heat water to produce steam to turn turbines>electricity
Drawback: habitat destruction and light beams frying birds mis air
Solar Energy PROs
No air pollutants (PM, SO, NO) released to gen electricity
No CO2 released when generating electricity
Renewable, unlike FF that will run out
No mining of fossil fuels for electricity production
Solar Energy Cons
Semiconductor metals (silicon) need to be mined to produce PV cells (solar panels)
This can disrupt habitats, pollute water with mine tailing, air with PM
Silicon is a limited resource
Solar panel farms can displace habitats
6.8 FRQ
The increased tracking ability such as the one or two-axis tracking PV array allows for an increased energy production for one kilowatt of solar PV capacity in comparison to a fixed tilt solar panel. This is because the PV cells can further.
LA is north of the equator, summer solstice is when it hits the earth the most which is why the energy production is the highest which is why it is about the same
When the earth starts tilting and is not hit directly by the sun, the days shorten so there is less opportunity for solar panels to capture sunlight so the axis helps
6.9 Hydroelectricity
How it works
Kinetic energy of moving water>spins a turbine with mechanical energy>turbine powers generator
Water moves with natural current of river/tides or vertically through dam channel
Largest renewable energy source
Largest producers: China, Brazil, US
Water Impoundments (dams)
Dams built in rivers create large artificial lake behind the dams (reservoirs)
Dams enable operators to control amount of water through the channel, increasing/decreasing electricity production
Also for control of flow downstream; prevention of season and prevent seasonal flooding
Reservoirs are source of reactional money (boating, tourism, increased prop values, fishing)
IMPACTS: flooding of ecosystems behind dam and sedimentation (buildup of sediments behind dam)
River system and Tidal energy
Dam diverts the natural current of a river through man-made channel
Less impactful to surround environment with no reservoir and no ecosystems being flooded
Doesnt stop natural flow of sediments; doesnt generate as much water and unavailable in warmer seasons when water levels are lower
Drawbacks of Hydrodams
Ecological: reservoir flood habitats behind dams
Prevents upstream migration of fish like salmon that go to spawning ground to reproduce
Sedimentation causes upstream to be warmer (less O2) with more sediments and downstream loses sediment, decreased water level, loses steambed hab
Environmental: FF combustion during dam construction; increased evap due to larger surface area of reservoir
Economic impacts: humans homes and businesses must be relocated due to reservoir flossing
Initial construction is very expensive (does create long term jobs tho soo)
Potential loss of fishing revenue is salmon breeding is disrupted
Fish Ladders
Cement “steps” or series of pools that migratory fish like salmon can use to continue migration upstream, around or over dams
Enables continued breeding for salmon, food sources for predators like birds, bears, dishing for humans
Benefits of Hydrodams
No GHG emission when producing electricity (initial construction does require)
Jobs created to maintain dam
reservoir/dam can be tourist attractions
Reliable electricity source for nearby
No air pollutants
Control of downstream seasonal flooding (use for hydroelectricity, recreation/scenic, flood control)
6.10 Energy
Natural radioactive decay of elements deep in earth’s core gives of heat
Water piped down into ground, heated by this heat
Hot water converted into steam>KINETIC ENERGY OF STEAM TURNS turbine> electricity or to heat homes directly
The heat from magma turns water>steam which is forced through pipes to spin a turbine
Water is cooled in cooling tower and returned to the ground to start process over
Renewable b/c heat from earth’s core wont run out, only is groundwater is returned after use
Ground Source Heat Pump
“” but technically heat does not come from from geologic activity FROM GROUND STORING HEAT FROM SUN
10 ft down, ground stays consistent 50-60 degrees from holding heat from sun
Heat is absorbing fluid pumped through pipe into ground where it takes heat from ground (winter) or gives off heat into ground (in summer)
heating
Piping water deep into ground to be heated by magma and then transfering heat from water>building
1000s of meters into ground to reach heater water reservoir
PRO
Potentially renewable if water is piped back into ground for reuse
Much less CO2 emission than FF
No release of (PM/SO/NO/CO)
CON
Not everywhere has access to energy
Hydrogen sulfide can be released, lethal/toxic to humans and animals
Cost of drilling deep into earth can be high initially (sometimes not worth it)
6.11 Hydrogen Fuel Cells
Hydrogen Fuel Cell Basics
Hydrogen is a renewable, alternative fuel source to FF
H2 and O2 are inputs used to create electricity w H2O as waste product
H2 gas enters fuel cell, split into protons (H+)and electrons by electrolyte membrane that only allows for protons to pass
Electrons take alternative route around the membrane>creates electrical current
O2 molecule break apart and combine w 2 hydrogens to create H2O byproduct
VEHICLES: replaces gasoline with H fuel
Creating H2 Gas
Have to obtain pure H gas (doesnt exists by itself as a gas naturally)
Serapting H2 gas from other molecules like H2O or CH4 is energy intensive
Steam reforming: burning natural gas (CH4) and using steam to separate the H gas from methane
Emits CO2 and requires FF input
Electrolysis: electrical current is applied to water to break it into O2 and H2
No CO2 emission, requires electricity
PROS
Can be stored in pressurized tanks, easy transport for different locations (not like solar, hydro, wind where must be used as soon as generated)
Used as fuel for vehicles (replacing gasoline) or ammonia for fertilizer
Gasoline replacement> EMITS NO AIR POLLUTANTS, ONLY H2O
Many industrial chemicals requires H2 gas
Can be stored as liquid/gas, easy for transport
H fuel cells are 80% efficient in converting chemical energy in H2 and O2 ino energy
CONS
95% of H2 production requires methane (CH4), based on nonrenewable source and CO2 releasing energy source
H fuel stores in gas form in vehicles would require larger tanks than current gasoline tanks
Products H2 gas and Oxygen goes through first reaction layer into proteins/electrons
Electrons produce electric current while protons flow through a membrane layer, on the other side they are combined with oxygen from the environment to create water vapor as the product
6.12 Wind Energy
Wind Turbine Electricity Generation
Kinetic energy of wind spins turbine>generator converts mechanical energy of turbine >electricity
Avg wind turbine has 15-30% capacity factor of total possible energy it could generate
Location
Clustered in groups in flat, open areas (usually rural)
Locating them together makes service, repair, and building transmission lines to them easier
Can share land with agricultural use
Offshore wind= wind farms in oceans/lakes
PROS:
Capitalized on the faster wind speeds
Environmental: Less damage due to decreased reliance on fossil fuels (less habitat destruction since there is less need for extracting natural gas and oil)
Economic: Increased creation of jobs such as construction, operation, and maintenance of the offshore wind project
Can also be used for tidal power:as the tides come in, propellers could be placed underwater to make energy
CONS:
Requires transmission lines built across long distances to reach land
Benefits
Non-depletable
No GHG emissions or air pollutants released when generating electricity
No CO2 (climate change) or No/SO/PM
Can shae land use (doesnt destroy habitats or cause soil/water contamination)
Drawbacks
Intermittency (isn't always available)
Can kill birds and bats
Considered eyesore or source of noise pollution by some
6.13 Energy Conservation
Small Scale Energy Conservation
Lowering thermostat to use less heat/AC less often
Conserving water (native plants instead of grass, low flow shower heads)
Energy efficient appliances, better insulation to keep more heat home
Large Scale Energy Conservation
Improving fuel efficiency
Subsidizing (tax credits) for electric vehicles, charging stations, hybrids
Increased public transport
Green building designs
Sustainable home
Using passive solar design to trap heat and decrease energy from heatings system
Well insulated walls/attic trap heat in winter/cool air from AC in summer (decreases electricity used)
Water conservation
Native plants require less watering than traditional lawns (increases biodiversity of pollinators, less fertilizer)
Low-flow showers, toilets, dishwater use less total water
Rain barrels allow rain water to be used for watering plants/cras
Transportation
Improving fuel economy of US vehicles that conserve energy w less gasoline/diesel needed
CAFE (corporate average fuel economy) standards are set in US to require auto manufacturers to make cars that meet standards or pay penalties
Hybrids have gasoline + electric engine
Electric vehicles like tesla or LEAF use no gasoline, but still require electricity
Public transit & carpooling
Buildings
Green roof or walls decrease runoff, absorb sun’s heat = ;ess need for cooling building and surround area
Sun lights on roof can decrease electricity used for lighting
Recycled materials reduce energy required to produce new ones (glass, wood)
7.1 Air Pollution Basics
Clean Air Act (1970) identified 6 criteria air pollutants that the EPA is required to set acceptable limits for, monitor, and enforce
SO2 (sulfur dioxide): from coal combustion used for electricity OR naturally from coal and oil
Effects: respiratory irritant, smog, and acid precipitation
NO & NO2 (Nitrogen Oxides): fossil fuel combustion OR forest fires, lighting, soil microbes in nature
Effects: formation of O3, photochemical smog, acid precipitation
CO (carbon monoxide): incomplete combustion, vehicle exhaust ( manure, charcoal, kerosene)
Effects: O3, lethal to humans
PM (particulate matter):fossil fuel and biomass combustion
Effects: respiratory irritant and smog
PM2.5: greatest health concern; lodges deeply in respiratory tract>>usually more toxic
PM10: too small to be filtered by respiratory tract>>health concern
O3 (ozone troposphere): from the photochemical oxidation of NO2
Effects: respiratory irritation, formation of smog, damaging to plant stomata so it limits growth
Pb (lead): metal plants, waste incineration (gasoline, paint in older buildings, toys and jewelry, pipes)
Effects: neurotoxicant
Air Pollutants vs. Greenhouse Gasses
CO2 is NOT an air pollutant as part of the Clean Air Act
It does not directly lower air quality as it is not toxic to organisms to breathe, not damaging to lungs/eyes, and does not lead to smog/decreased visibility
CO2 is a GREENHOUSE GAS: it leads to earth warming and thus env and human health consequences
Use fire air pollutants on FRQS: SO2, NOx, O3, PM
Coal Combustion
Releases more air pollutants than other FFs: ~35% of global electricity
Releases CO, CO2, SO2, NOx toxic metals (mercury, arsenic, lead), and PM (often carries toxic metals
Impacts of SO2:
Respiratory irritants
sulfur aerosols block incoming sun=reduces visibility, photosynthesis
Forms sulfurous (grey) smog
Combines with water and O2 in atmosphere to form sulfuric acid>acid precipitation
Nitrogen Oxides (NOx)
Released by combustion of FFs and biomass (NO and NO2)
NO forms when N2 combines with O2 (like during combustion)
NO can become NO2 by reacting with O3 or O2
Sunlight converts NO2 back into NO
Env. and human health impacts:
Resp. irritants
Leads to tropospheric ozone (O3) formation>photochemical smog
Combines with water and O2 in atm. To form nitric acid>acid precip.
EPA and Lead
Vehicles made after 1974 are required to have catalytic converters to reduce NOx, CO, and hydrocarbon emissions (aka known as neurotoxicant-damages nervous systems of humans)
Primary vs. secondary air pollutant
Primary: Emitted directly from sources such as vehicles, power plants, factories, power plants, factories, or natural sources
NOx, CO, CO2**, VOCs, SO2, PM, hydrocarbons
Secondary: primary pollutants that have transformed in presence of sunlight, water, O2
Occur more during the day b/c sunlight usually drives formation
Tropospheric O3 (ozone), sulfuric acid (H2SO4) & sulfate (SO42-). Nitric acid (HNO3) & nitrate (NO3-), acid rain, photochemical smog,
7.2 Photochemical Smog
Secondary form of pollution forming when NOx chemicals mix with VOCs in sunlight forming other pollutants
NOx form in the morning and peak in the afternoon (occurs more often in summer when sunlight is at its peak
Water and oxygen in the atmosphere react with NOxs and form: Ozone; PANS (peroxyacyl nitrates, Acid Deposition
Precursors
NO2 is broken by sunlight into NO + O
Volatile organic compounds that bind with NO and form photochemical oxidants
Carbon-based compounds that evaporate easy
Sources: gasoline, formaldehydrade, cleaning fluids, oil-based paints
O3 forms when NO2 is broken by sunlight and free O binds to O2
Resp irr in troposphere
Damaging to plant stomata>limits growth
Conditions
Sunlight drives O3 formation by breaking down NO2> NO + O then free O atom binds to O2
Warm: hotter atm. Temp speeds O3 formation, evaporation of VOC and thus smog formation
Normal O3 formation
Sunlights breaks NO3> NO + O2
O binds with O2 to form O3
At night, O3 reacts with NO to form NO2 and O2, O3 levels drop overnight
O3 formation peaks in afternoon when sunlight is most direct and NO2 emissions from morning traffic have peaked
Morning commute>high NO2 levels from car exhaust
Photochemical Smog Formation
Sunlight breaks NO2> NO + O
O bonds with O2 to form O3
VOCs bonds with NO to form photochemical oxidants
Without NO to react with O3, builds up instead of returning to O2 and NO2 overnight
O3 combines with photochemical oxidants (NO + VOCs) to form photochemical smog
Factors that increase smog formation
More sunlight (summer, afternoon) = more O3
Warmer temp speeds evap of VOCs that lead to O3
Higher VOCs emissions (gas stations, laundromats, plastic factories, petrochem factories)
Increased vehicle traffic; increases NO2 emissions and therefore O3 formation
Impacts of Smog
Environmental: reduced sunlight>limits photosynthesis
O3 damages plant stomata and irritates animal resp tracts
Humans: resp irritant, worsens asthma, bronchitis, COPD, irritates eyes
Economic: increased health care costs to treat asthma, bronchitis, COPS
Lost productivity due to sick workers missing work or dying
Decreased ag. Yields due to less sunlight reaching crops and damage to plant stomasa
Reduction of SMOG
Vehicles: decreasing the # of vehicles on the road decreases NO2 emissions
Fewer vehicles = less gas= less VOCs
Carpooling, public transport, biking, walking, working from home
Energy: increased electricity production from renewable sources that don't emit NO (solar, wind, hydro)
Nat gas power plants release for less NO than coal
7.3 Thermal Inversion
Urban Heat Island Effect
Urban areas tend to have higher surface and air temp than surrounding suburban and rural areas due to:
Lower albedo: concrete and asphalt absorb more of sun’s energy than areas with more vegetation (absorbed sunlight is given off as IR radiation-heat)
Snow is higher albedo>keeps cooler
Less evapotranspiration: water evaporating from surfaces and transportation from surfaces and transpiration from plants carries heats from surface into the atmosphere
This cools off rural and suburban areas which have more vegetation
Thermal Inversion
NORMALLY, the atmosphere is warmest at earth’s surface and cools as altitude rises
Warm air rises> air convection carries air pollutants away from earth's surface and distributes them into higher into the atmosphere
During thermal inversion>> cooler air mass becomes trapped near earth's surface
Due to warm front OR due to hot urban surfaces coling overnight whole IR radiation absorbed during day is still being released
CITIES MOST PRONE DURING WINTER: HAVE TO BE FAR ENOUGH N/S TO HAVE DISTINCT WINTER
Cold air at the surface is trapped beneath the warmer mass above, convection doesnt carry pollutants up and away
Effects of Thermal Inversion
Air pollutants (smog, PM, ozone, SO2, NO2, PM10, PM2.5, Woodsmoke) trapped closer to earth
Respiratory irritation: asthma flare ups>hospitalization, worsened COPD, emphysema
Decreased tourism revenue
Decreased photosynthetic rate
Regulations
Increased public transportation
Limited vehicle permits
Emission testing for personal and commercial vehicles
Restrictions on agricultural burning, waste-burning, coal-burning power plants
Educational and incentive programs
Los Angeles is a highly populated city with much car traffic. It also sits next to the Pacific Ocean and receives cool prevailing winds that are trapped by nearby mountains. This cool air is much denser in comparison to the hot surface air found over the land. As a result, the cool air sinks below the warm air.
7.4 Atmospheric CO2 and PM
Natural Sources of Air Pollutants
Lightning strikes: convert N2 in atm. to NO
Forest fires: CO, PM, NO
Combustion of biomass also releases CO2 and H20 vapor
Plasts (esp conifers): plants emit VOC
Volcanoes: SO2, PM, CO, NO
Natural Sources of CO2 and PM
Respiration: all living things release CO2 through respiration
Natural PM sources: sea salt, pollen, ash from forest fires and volcano dust
Leads to haze
Aerobic decomposition: decomposition of organic matter by bacteria and decomposers in the presence of oxygen>> releases CO2
Anaerobic decomposition: decomposition of organic matter by bacteria and decomposers in low or oxygen -free conditions> releases CH4/methane
PM10 vs PM2.5
Particulate matter: solid or liquid particles suspended in air
PM10 (<10 micrometers)
Particles or droplets like dust, pollen, ash, mold
Too small to be filtered by nose hairs and trachea cilia
Nose hairs and mucous secretions in our nose and throat trap larger particles and prevent larger particles from getting to our lungs
Can irritate respiratory tract and cause inflammation
PM2.5 (<2.5 micrometers)
Particles from combustion (esp vehicles) smaller dust particles
Most likely to travel deep into the lungs due to smaller size
Associated with chronic bronchitis and increased risk of lung cancer
7.5 Indoor Air Pollutants
Developing vs. Developed Countries
Developing nations use more subsistence fuels like wood, manure, charcoal
Release CO, PM, NOx, VOCs, cause deforestation
Often combusted indoors with poor ventilation=high concentrations
Developed nations use more commercial fuels (coal, oil, natural gas) supplies by utilities
Typically burned in closed, well ventilated furnaces, stoves, etc
Major indoor air pollutants come from chemicals in products; adhesives in furniture; cleaning supplies; insulation; lead paint
PM & Asbestos
Particulates are a common indoor air pollutant (ex. Smoke, dust, asbestos)
Asbestos is a long, silicate particle previously used in insulation (linked to lung cancer & asbestosis)
Out of use but remains in older buildings
Not dangerous until insulation is disturbed and asbestos particles enter air & resp tract
Should be removed by trained professionals with proper respiratory equipment, ventilation in area its being removed from, plastic to seal off area from rest of building
CO (Carbon Monoxide)
Produced by incomplete combustion of any fuel (not all fuel combusted w low O2 or temp)
CO is an asphyxiant: causes suffocation due to CO binding to hemoglobin in blood, displacing O2
Lethal to human in high concentrations, esp with poor ventilation (odorless/colorless)
Developed nations: CO released into home by malfunctioning natural gas furnace ventilation (detected by carbon monoxide detectors)
Developing nations: CO emitted from indoor biomass combustion for heating/cooking
VOCs (volatile organic compounds)
Compounds or molecules that vaporize and become airborne at low temperatures
MUST CONTAIN CARBON
Chemicals used in variety of home products that easily vaporize, enter air, irritate yes, lungs, bronchioles
Natural VOC: volcanoes/forest fires release benzene
adhesives/sealants: chemicals used to glue carpet down, hold furniture together, seal panels
Formaldehyde is a common adhesive in particle board and carpet glues
Cleaners: common household cleaners and deodorizers like febreeze
Plastics and fabrics: both can release VOCs or from adhesives used in production
Radon Gas
Radioactive gas released by decay of uranium naturally found in rocks underground (esp granite)
Usually enters homes through cracks in foundation, disperses up from basement/foundation through home
Can seep into groundwater sources + enter body through drinking water
2nd leading cause of lung cancer after smoking
EPA recommends testing homes with airborne radon monitor
Sealing cracks in foundation can prevent it from entering/increasing ventilation in home can disperse if its detected
Dust and Mold
Natural indoor air pollutant that can worsen asthma, bronchitis, COPD, emphysema
Dust settles in homes naturally, distrubed by movement, enters air and then resp tract
Mold develops in dark, damp areas that aren't well ventilated
Black mold releases spores into air; harmful to resp. system
Can be removed physically cleaning mold out + fixing water leak/ventilation issue that led to mold formation
Lead
Found in paint in old homes (EPA banned lead paint in 1978)
Paint chips off walls/windows and is eaten by children or inhaled as dust
Lead water pipes also release lead into drinking water sources, less common than lead paint
Damages central nervous system of children due to smaller size + developing brain
Can be removed by strippnig lead paint, replacing with non-lead based paint; lead water pipes replaced with copper pipes
7.6 Reduction of Air Pollutants
Reducing emissions=reducing air pollutants
Drive less, walk/bike/bus more
Conserve electricity (smart appliances)
Eat more plants, less meat
Renewable, non-pollution emitting energy
Laws/Regulation
Clean Air Act: allows EPA to set acceptable levels for criteria air pollutants
Monitor emission levels from power plants and other facilities
tax/sue/fine corporation that release emissions above levels
CAFE Vehicle standards: (corporate average fuel economy) standards require the entire US fleet of vehicles to meet certain average fuel
Requires vehicle manufacturers to work to make more efficient vehicles
More efficient vehicles burn less gasoline and release less NOx, PM, CO, CO2
Pollutant Credits: similar to ITQs for fish
Companies that reduce emissions well below EPA-set levels earn pollution credits
They can sell these to companies that release more than acceptable levels
Reducing Vehicle Air Pollutant
Vapor Recovery Nozzle: captures hydrocarbon VOCs released from gasoline fumes during refueling
Separate tube inside nozzle captures vapors, returns them to underground storage tank beneath gas station
Reduces VOCS(reduce smog, resp irritants), benzene (carcinogen)
Catalytic Converter: required on all vehicles after 1975
Contains metals (platinum & palladium) that binds to CO & NOx & hydrocarbons to convert into CO2, N2, O2, H2O
Reducing SOx & NOx
Crushed Limestone (SO2): used to reduce SO2 from coal power plants
Crushed coal mixed w limestone before burned in boiler
Calcium carbonate in limestone + SO2 = calcium sulfate >reduced SO2 emitted
Used for gypsum wallboard or sheetrock 4 home foundations
Fluidized Bed Combustion (NOx): fluidizing jets of air pumped into combustion bed
Jets of air bring more O2 making combustion more efficient + bringing more SO2 into contact w calcium carbonate in limestone
Allows coal to be combusted at lower temp>emits less NOx
Wet & Dry Scrubbers
Dry Scrubbers (NOx, SOx, VOCs): large column/pipe w chemicals that absorb or neutralize oxides (NOx, SOx, VOCs) from exhaust streams
Calcium oxide is a common dry scrubber additive, reacts w SO2 to form calcium sulfite
Wet Scrubbers (NOx, SOx, VOCs, PM): involves chemical agents that absorb or neutralize NOx, SOx,VOCs, mist nozzles that trap PM in water droplets
Mist droplets with pollutants and PM trapped in fall to bottom of scrubber or get trapped @ top by mist eliminator
Sludge collection system traps polluted water for disposal
Reducing PM
Electrostatic Precipitator: power plant/factory emissions passed through device with a neg. charged electrode gives particles a neg charge
Neg. charged particles stick to pos charged collection plates, trapping them
Plates discharged occasionally so particles fall down into collection hopper for disposal in landfills
Baghouse Filter (PM): large fabric bag filters that trap PM as air from combustion/industrial processes pass through
Shaker device knocks trapped particles loose into collection hopper below
PM collected & taken to landfill
Difference between “good” ozone and “bad” ozone
Function of the ozone layer?
To absorb the sun’s harmful UV rays, allowing just enough for life on earth
Ozone Layer Formation
Step 1: O2 + ultraviolet rays = O + O
Step 2: O + O2 = O3
CFCs:
Chlorofluorocarbons
Nontoxic, nonflammable
Contain C, Cl, F
Found in refrigerants, propellants (aerosols), foam, and packing materials
UV causes a chlorine atom to break away from the CFC molecule
Free chlorine atom hits an ozone molecule
The chlorine atom pulls 1 oxygen atom away
A free oxygen atom hits the chlorine monoxide molecule
Results in another free chlorine atom
Free chlorine will continue to deplete ozone in the stratosphere
Montreal protocol: limited/banned CFCs in many countries
7.7 Acid Rain
Sources of NOx & SO2
SO2: coal fired power plants. Metal factories, vehicles that burn diesel fuel
NOx: vehicle emissions, diesel generators, coal power plants
Limiting Acid Rain (decreased after clean air act)
Reducing NOx & SO2 emissions reduce acid deposition
Higher CAFE standards
More public transit
Renewable energy sources
More efficient electricity use
NOx & SO2 react with O2 and H20 in the atmosphere, forming nitric and sulfuric acid
Sulfuric acid and nitric acid dissociate in the presence of water into sulfates and nitrate ions and hydrogen ions (H+)
Acidic rain water (higher H+ conc) decreases soil and water pH
Limits tree growth in forests down wind from major SO2 and NOx sources
Env. effects of Acid Rain
acidity= higher H+ ion concentration, lower pH
soil/water acidification:
H+ ions displace or leech other pos. Charge nutrients (Ca2+, K+) from soil
H+ ions make toxic metals like aluminium & mercury more soluble in soil and water
Slows growth or kills plants and animals living in the soil or water
pH tolerance:
As pH decreases outside optimal range for species, pop. declines
When pH leaves range of tolerance, they cannot survive due to aluminium toxicity, disrupted blood osmolarity (Na+/Cl- balance disrupted at low pH)
Indicator species can be used to determine conditions of an ecosystem (soil, water, etc.)
Mitigating Acid Rain
Limestone (calcium carbonate) is a natural base to neutralize acidic soil/water
Limestone: calcium carbonate reacts with H+ ions = HCO3 + Ca 2+
Neutralizes acidic water/soil, moving pH closer to 7
Regions with limestone bedrock have natural buffering of acid rain (humans can also add crushed limestone to soils/waters to neutralize)
Acid rain can corrode human structures, esp made of limestone
Limiting SO2 & NOx: decreasing primary pollutants that drive acid rain to reduce
Renewable energy sources, decreasing coal comb; fluidized bed combustion & lower burning temp. For existing coal power plants; dry or wet scrubbers
7.8 Noise Pollution
Urban noise pollution: any noise at great enough volume to cause physiological stress(dif hearing, headaches, confusion) or hearing loss
Construction: jack hammers, trucks, concrete pouring
Transportation: cars, buses, trains
Industrial activity: manufacturing plants
Domestic activity: neighbor’s music, lawn mowing, home projects
Wildlife Effects (land)
Noise pollution can disrupt animal communication, migration, and damage hearing
Physiological stress: caterpillar hearts beat faster when exposed to stimu;ated highway noise pollution
Could drive pollinator species decline
Hearing: can prevent predators from hearing prey and vice versa; can prevent mats from locating each other (decreases chances of survival)
Wildlife Effects (aquatic)
Aquatic noise pollution comes from the noise of ship engines, military sonar, and seismic air blasts from oil and gas surveying ship
Physiological stress: hearing loss, disrupted communication, mating calls, predator and prey navigation
Whales are especially prone to having migration routes disputed as vocal communication is disrupted
animals that rely on sonar or sound for navigation, feeding and communication can be disoriented by mechanical sounds and sonar used by humans.
Seismic surveying: ships send huga air blasts down into the water, searching for oil by recording how the echo is returned from ocean floor
So loud that researchers off the coast of virginia cn detect blasts from coast of brazil
Explain one way that you can modify this procedure to better determine the impact of fossil fuel combustion on sulfur dioxide levels.
Maybe burn some coal: lignite, bituminous, and anthracite to allow for a wider variety as coal is a fossil fuel, and the combustion of coal is an anthropogenic source of sulfur dioxide which will allow to make better conclusions
Adjust the temperature the fossil fuels are being burned
Change volume of the burning
Locations with the highest levels of tropospheric ozone? Dallas, Texas because it is bright/sunny
Describe the relationship between the max daily temperature and max daily ground level ozone that is shown by this data
As the maximum ground level ozone increases, the temperature increases as a exponential relationship
a. Describe the trend that you observe in the figure between altitude B and C
Between B and C, the altitude is increasing as the temperature is increasing positively in which the directionality is different from before and after
B. Identify one pollutant that would increase in concentration due to the temperature anomaly between B and C.
One pollutant that would increase in concentration would be tropospheric ozone, O3,
c. explain how the trend you obsessed in a could lead to increased effects of the pollution you identified in b
There is a temperature inversion occurring in which the trend is going against the normal trend of temperature decreasing with the increasing altitude. The thermal inversion traps pollution closer to the ground and as the cold air is trapped beneath the warmer mass above, the convection does not carry the pollutants away
a. Explain the method that will be used to collect and analyze data
To collect particulate matter density, a card wi
b. Describe the variables in the investigation
The independent variable is; how will it be manipulated?
The dependent variable is; how will it be measured
c. describe the factors that will be controlled in the study
What are being constant and why
AP Environmental Science Course Review Part 3
6.2 Global Energy Consumption
The use of energy resources is not evenly distributed between developed and developing countries
The most widely used sources of energy are fossil fuels
As developing countries become more developed, their reliance on fossil fuels for energy increases
Developed vs Developing Countries
Developed nations use more energy on a per capita basis but developing nations use more energy in total (higher pop)
Developing nations are still industrializing & pop is still growing rapidly
Also increase on per/person as countries industrialize + residents achieve higher standards of living
Fossil fuels
Most common fuel source globally
oil>gasoline=main fuel for vehicles
coal=main fuel for electricity
Natural gas=secondary fuel for electricity and main fuel for heating
Hydroelectric energy (dams used to create electricity) are 2nd largest source of energy
Water spins a turbine which generates electricity
nuclear energy is the 3rd largest source
Uranium fission releases heat to turn water into steam to turn a turbine >generate electricity
Development increases Fossil Fuel Consumption
Many residents of less developed countries depend on subsistence fuels (biomass that can be easily gathered/purchased and used)
Wood, charcoal, dried animal manure (can drive deforestation)
Economic development>wealth>higher per capita GDP>energy use
As developing nations develop, fossil fuel consumption increases
Factors that affect energy source
Predominant energy source until 1875: wood>coal>1950s: nuclear>oil, natural gas, coal
Availability: what fuels can consumers get?
Price: supply and demand
Governmental regulation: what fuels can consumers get?
6.3 Fuel Types and Uses
Subsistence fuels
Biomass fuel sources that are easily accessible; often used in developing countries as a home heating or cooking fuel
Wood (and charcoal) are the most common fuel sources in developing nations
Wood is free/cheap to cut down and utilize as fuel, can cause deforestation and habitat loss
Charcoal is made by heating wood under low O2 conditions for long time
Peat is partially decomposed organic matter (usually ferns or other plants) found in wet, aidic ecosystems like bogs and moors
Can be dried and used as a biomass fuel source
Coal formation
peat>lignite>bituminous>anthracite
Pressure from overlying and sediment layers compacts peat into coal over time
Depper a coal reserve is buried, the more pressure from overlying rock layer>more energy dense
Anthracite is the most valuable form of coal
Coal is burned to heat water into steam, to turn a turbine that generates electricity
Peat (not a coal: partially decayed plant matter in swamps/bphs
Lignite (brown coal): low heat content, low sulfur content, limited supplies in most areas
Bituminous coal (soft coal: extensively used as fuel b/c of high heat content, high heat content
Anthracite: best quality, high heating capacity, lowest sulfur content (CLEANEST)
Mining Basics
Ore: commercially valuable deposits of concentrated minerals that can be harvested and used as raw materials
Metals: elements that conduct electricity, heat, and have structura properties for building ( found within ores)
Reserve: known amount of a resource left that can be mined
Usually measured in years left of mining
Overburden: soil, vegetation, rocks that are removed to get to an ore deposit below
Tailings & Slag: leftover waste material separated from the valuable metal or mineral within ore (often stored in ponds @ mine site) MESS
Surface Mining
Removal of overburdened to access ore near surface
Different types of surface mining: Open pit, Strip mining, placer, mountaintop removal
Mountaintop removal: esp damaging to landscape and habitats, streams nearby
Removal of vegetation/ soil= topsoil erosion, habitat loss, increased stream turb, increased PM (particulate matter) in air
Strip mining: removal of strips of soil/rock to expose ore
Remove material, extract resource, return mining spoils/tailings
Coal, sand
Open-pit mining: uses a large visible pit/hole
Resource close to surface
copper
Mountaintop removal: with explosives
Tailings deposited in nearby regions
Placer mining: looking for minerals and metals in river sediments
Diamonds, tantalum, gold (CA gold rush)
Subsurface Mining
More expensive due to high rinsurance/health care costs for workers
Risks: poor ventilation>toxic gas exposure, mine shaft collapse, injury from falling rock, lung cancer, asbestos, fires, explosions
Vertical “shaft” drilled down into ground
Elevator to carry down workers & transport out resource
Often used for coal
Increased used as surface coal deposits are depleted
Environmental Impacts of Mining
Contamination of surface and groundwater with acidic mine drainage
Habitat destruction
Release of dust and harmful gases such as methane and H2S
Rainwater carries sulfuric acid into nearby streams, infiltrates ground water
Lowers pH of water, making toxic metals like mercury/aluminum more soluble in water source (kills aquatic organisms)
Methane release: coal mining releases methane gas (CH4) from rocks around coal
Vented out of mine to prevent explosion and continues seeping out after mine closes
GHG>>>CLIMATE CHANGE
PM (particulate matter) release: coal mining especially releases lots of soot and other particulates that can irritate human and animal lungs
Mine Reclamation
Process of restoring land to original state after mining has finished
Includes
Filling of empty mine shaft/hole
Restoring original contours of land
Returning topsoil with acids, metals, and tailings removed
Replanting of native plants to restore community to as close to original state as possible
Mining Legislation
Mining law of 1872 (general mining act):
Allows individuals and companies to recover ores and fuels from federal lands
Few provisions for environmental protection
Surface mining control and reclamation act (1977):
Land must be minimally distributed during coal mining and then reclaimed
Related legislation: clean air act, clean water act, superfund act
Natural Gas
Decaying remains of plants and animals (mostly marine life) are buried under layers of rock and converted by pressure into oil (petroleum) and natural gas over time
Natural gas is mostly methane (CH4) and is found on top of trapped oil (petroleum) deposits
Forms when oil is trapped in a porous, sedimentary rock underneath a harder, impermeable rock layer that doesnt let the gas escape
Considered the cleanest fossil fuel (produces the fewest air pollutants and least CO2 when burned)
Produces about 1/2 as much CO2 as coal when burned to generate electricity
Produces virtually no PM (ash/soot)
Produces less SO4, NO2 than coal/oil and no mercury
Crude Oil (petroleum)
Decaying organic matter trapped under rock layers is compressed into oil over time
Extracted by drilling a well through the overlying rock layers to reach the underground deposit and then pumping liquid oil out under pressure
Can also be received from tar sands (combination of clay, sand, water, and bitumen)
Bitumen is a thick, sticky, semi-solid form of petroleum (not liquid)
Extracting & using oil from tar sand is extremely energy and water intensive
Lots of water needs to be heated (requiring energy) to create steam thats piped down into the tar sand to melt the bitumen into a liquid that can flow up a pipe
Lots more water is used to separate the oil from all of the impurities (sand, clay) at the refinery
6.4 Distribution of Natural Energy Resources
Fossil Fuel Products
Crude oil (petroleum) is converted into lots of different products through the process of fractional distillation
Crude oil is burned in a furnace and water vapor passes into a column where different hydrocarbons are separated based on their boiling points
hydrocarbons w/ lower boiling points gather at the top of the column, higher boiling points gather at bottom
Different hydrocarbons within petroleum are used for different products
Petroleum gas (PUMPING OF VISCOUS LIQUID)
Gasoline (fuel for cars)
Naphtha (used to make plastic)
Jet fuel
Diesel fuel
Motor oil
Bitumen (asphalt for roads)
FF Energy Reserved
Coal (100-150 years left)
US, Russia, China, Australia
Natural Gas (50-60 years left)
Russia, iran, qatar, US, saudi Arabia
Oil (50ish years left)
Venezuela, saudi arabia, iran, canada, iraq
Fracking and Shale Gas
Hydraulic fracturing (aka fracking) is method of natural gas extraction that has extended access to natural gas
Gas trapped in semi-permeable sedimentary rock layers like shale is released by cracking the rock with pressurized water
Well is made; pipe is inserted; fracking fluid is inserted; gas flows out
Fracking natural gas from shale rock increases/extended supply of natural gas
Can contaminate water/destroy habitat; pipe is not lined properly, may contaminate water; fracking fluid has volatile organic compounds (VOCs); Leads to earthquakes from breaking rock and destabilizing the ground from the pressure
Shale Gas Reserves
FF are non-renewable and will eventually be depleted, but short-term economic profit still drives extraction and use
Discovered but unharvested reserves rep economic benefit to countries
Tar/Oil Sands
Bitumen deposits where crude oil can be recovered but with higher water & energy inputs
Canada: alberta region = world’s largest oil sands reserve
tar/oil islands extraction extends the world’s supply of crude oil
6.5 Fossil Fuels
Fossil Fuel Combustion
Reaction between O2 and fossil fuels releases energy as heat and produced CO2 and H2O as products
Combustion is step in carbon cycle (Hydrocarbons -FFs- are burned to release energy and the carbon stored in them reacts w O2 in the air to form CO2
Methane (natural gas), gasoline, propane, butane, coal are fossil fuels (hydrocarbons) that release energy in the same way
wood/biomass work same
FF to Generate Electricity
The #1 source of electricity production globally is coal, then natural gas
Heat> water into steam> steam turns a turbine, turbine powers generator> generator produces electricity
Coal, oil, natural gas, biomass, and trash acn all be burned to drive this same process and create energy
Nuclear energy works similarly, nuclear fission prodicing inital heat
Environmental Consequences>COAL
Habitat destruction to clear land for mining
Produces pollutants and relases CO@ (GHG> global warming)
Releases more CO2 than other FF when burned for electricity
Release PM (soot, ash) which can irritate respiratory system
Produces toxic ash contaminated w lead, mercury, and arsenic
Taken to landfills, stored in ash ponds which can leak into ground/surface water or into soil
Releases sulfur and nitrogen oxides which irritate resp systems and contribute to smog and acid precipitation
Generating Electricity
Coal is 30% efficient for generating electricity
Nat. gas is 60% efficient
Much of energy “lost” or not converted into electricity escapes as heat
Cogeneration: when heat produced from electricity generation is used to provide heat (air and hot water) to a building
CHP (combined heat and power) systems are close to 90% efficient
Environmental consequences: tar sands
Habitat destruction to clear land (biodiv loss)
Ground or nearby surface water depletion (H20) needed for steam and washing impurities from bitumen at refinery
Water contamination: tailing ponds can overflow and run into nearby surface waters or leach into groundwater
Carcinogen salts, acids, hydrocarbons, bitumens all toxic to plants/animals
CO2 released b machinery during extraction, transport, refinement
Environmental consequences: crude oil/petroleum
Possibility of spill (from tanker ships or pipeline)
Spills in water= crude oil covering sun, clogging fish gills, suffocating ocean animals, sticking to bird feather
Spills on land= toxic to plant roots, surface, or groundwater contamination
Habitat or fragmentation when land is cleared for roads, drilling equipment, pipelines
Fracking (Hydraulic Fracturing)
Used to extract natural gas from sedimentary rock
Vertical well is drilled down
How is energy produced in a coal-fired power plant
Coal is burned, creates steam through the boiling water, steam turns turbine, turbine turns generator, generator creates electricity
One environmental issue that can arise from combustion of fossil fuels
Mining for resources, pulverized coal, water use, carbon dioxide production
6.6 Nuclear Energy
Nuclear fission and radioactivity
A neutron is fired into the nucleus of a radioactive (unstable) element, such as uranium
Nucleus breaks apart and releases lost of energy (heat) and more neutrons that break more nuclei, releasing more energy (chain reaction)
Radioactivity refers to the energy given off by a nucleus of a radioactive isotope (uranium-235)
Radioactive nuclei decay or breakdown and give off energy (radiation) without fission, nuclear fission releases tons of energy all at once
Radioactive half life= amount of time it takes for 50% of a radioactive substance to decay (breakdown)
10 half-lives generally means saftey
Cobalt-60 takes 5.37 yrs to undergo half life
20 g is the 100% and undergoes half-life (5.27 years)= 10 g left (50%)
Half life #2 is 5g (25%)
Generating electricity
heat> water into steam>steam turns a turbine>turbine powers generator>generator produces electricity
U-235 stored in fuel rods, submerged in water in reaction core, heat from fission turns H20>steam> turns turbine>powers generator> makes electricity
Control rods are lowered into reactor core to absorb neutrons and slow down reaction, preventing meltdown/explosion
Water pump brings in cool water to be turned into steam and cools reactor from overheating
Nonrenewable, but cleaner than FF
Is nonrenewable b/c radioactive elements like uranium is limited
No air pollutants or CO2/CH4 released when electricity is generated, mining of uranium, plant construction stil release GHG
Only gases released from elec gen is water vapor (technically GHG but stays in atm briefly)
Spent fuel rods: used fuel rods remain radioactive for millions of years and need to be stored in lead containers on site @ nuclear PP
Mine tailing: leftover rock and soil from mining have radioactive elements to contaminate soil/water nearby
Water use: nuclear PP require lots of water and can deplete surface/groundwater sources
Thermal pollution: hot water from PP released back into surface water can cause thermal shock (decreased O2 and suffocation)
Nuclear meltdowns
Three Mile island (US): partial meltdown due to testing error, radiation released but no deaths/cancer
Fukushima (japan): earthquake and tsunami triggered cooling pump failure that led to meltdown (explosion of reactor core) and widespread radiation release
Chernobyl (ukraine): stuck cooling valve during test elad to complete meltdowns, several deaths + widespread radiation release
Contaminated soil: radiation can remain in soil and harm plants and animals in the future
Radiation spread: radiation can be carried by the wind over long distances
6.7 Energy from Biomass
Biomass vs. Biofuels
Biomass: organic matter (wood/charcoal, dried animal waste, dead leaves/brush) burned to release heat- mostly for heating gomes/cooking
Utilized primarily in developing world for heating homes/cooking
Easy to harvest, available, cheap/free (subsistence fuel)
Can be burned in PP to generate electricity(less common than FFs)
Biofuels: liquid fuels (ethanol, biodiesel)
Used as replacement fuel sources for gasoline, primarily in vehicles
Modern vs fossil carbon
Biomass burning CO2 but does not increase atmospheric CO2 levels like FF burning
Burning biomass releases modern carbon (CO2 that was recently taken out of the atmosphere); FF burning releases fossil carbon that has been stored for millions of years
Biomass burning considered carbon neutral
Humanhealth and env consequences of biomass burning
Releases CO, NO3, PM, VOCs-volatile organic compounds-(respiratory irritants)
3 billion people globally cook an open biomass fires (developing world)
Biomass bruns indor worsens asthma, bronchitis, COPD, emphysema
Environmental consequences=deforestation and air pollutants
Biofuels: ethanol and algae
Corn and sugarcane are fermented into ethanol which is mixed w gasoline
Corn grain/sugar cane broken down and yeast ferments sugar>ethanol
E85 or flex fuel= 51-83% ethanol + gasoline mix
Decreases oil consumption for transportation, but is less efficient than pure gasoline
“Renewable” only to extent of production of corn is sustainable (sugar cane is a perennial= more sustainable)
Environmental consequences= all the neg. consequences of monocrop org
Soil erosion, hab. Loss, GHG release (soils, tractors, fertilizers), H2O use
Lots of corn needed, relative to petroleum, can compete w human consumption of corn
Algae produce oils that can be used as biofuels more sustainably than corn
Biodiesel
Liquid fuels produced specifically from plant oils (soy, canola, palm)
Palm oil biodiesel has been found to produce 98% more GHG than FF from clearing of forests for palm plantations
One resource that can be combusted to provide heat and describe a neg consequence that results
Wood can be combusted to provide heat that results in deforestation depending on the location
Describe a potential solution to the negative consequence to part a
Government regulation or efforts to regulate forest growth
One source of biofuel that causes loss of habitat and solution to produce biofuels with decreased habitat impact
Brazil forests or in gee, solution cou
6.8 Solar Energy
Active vs Passive solar energy
Passive: absorbing or blocking heat from the sun w/o use of mechanical electrical equip
Using sun’s heat to cook food in a solar oven
Orienting building design to block sunlight in warmer months and allow sunlight in during colder months
Active: use of mechanical/electrical equip to capture sun’s heat (solar water heaters or CST- concentrated solar thermal) or convert light rays directly into electricity (PV cells)
Solar water heaters capture suns heat in water or circulating fluid and transfer heat to warm water for home
Photovoltaic Cells
Aka solar panels; contain semiconductor (usually silicon) that emits low voltage electrical current when exposed to sun
Photons (particles carrying energy from sun) cause separation of charges between 2 semiconductors layers, electrons sep from protons and flow through circuit to load, delivering energy as electricity
Drawback: intermittency (solar energy can only be generated during the say)
Could be solved by cheaper, larger batteries that can store energy generated during teh day for use at night (not currently available)
Concentrated Solar Thermal (CST)
Heliostats (mirrors) reflects sun’s rays onto a central water tower to heat water to produce steam to turn turbines>electricity
Drawback: habitat destruction and light beams frying birds mis air
Solar Energy PROs
No air pollutants (PM, SO, NO) released to gen electricity
No CO2 released when generating electricity
Renewable, unlike FF that will run out
No mining of fossil fuels for electricity production
Solar Energy Cons
Semiconductor metals (silicon) need to be mined to produce PV cells (solar panels)
This can disrupt habitats, pollute water with mine tailing, air with PM
Silicon is a limited resource
Solar panel farms can displace habitats
6.8 FRQ
The increased tracking ability such as the one or two-axis tracking PV array allows for an increased energy production for one kilowatt of solar PV capacity in comparison to a fixed tilt solar panel. This is because the PV cells can further.
LA is north of the equator, summer solstice is when it hits the earth the most which is why the energy production is the highest which is why it is about the same
When the earth starts tilting and is not hit directly by the sun, the days shorten so there is less opportunity for solar panels to capture sunlight so the axis helps
6.9 Hydroelectricity
How it works
Kinetic energy of moving water>spins a turbine with mechanical energy>turbine powers generator
Water moves with natural current of river/tides or vertically through dam channel
Largest renewable energy source
Largest producers: China, Brazil, US
Water Impoundments (dams)
Dams built in rivers create large artificial lake behind the dams (reservoirs)
Dams enable operators to control amount of water through the channel, increasing/decreasing electricity production
Also for control of flow downstream; prevention of season and prevent seasonal flooding
Reservoirs are source of reactional money (boating, tourism, increased prop values, fishing)
IMPACTS: flooding of ecosystems behind dam and sedimentation (buildup of sediments behind dam)
River system and Tidal energy
Dam diverts the natural current of a river through man-made channel
Less impactful to surround environment with no reservoir and no ecosystems being flooded
Doesnt stop natural flow of sediments; doesnt generate as much water and unavailable in warmer seasons when water levels are lower
Drawbacks of Hydrodams
Ecological: reservoir flood habitats behind dams
Prevents upstream migration of fish like salmon that go to spawning ground to reproduce
Sedimentation causes upstream to be warmer (less O2) with more sediments and downstream loses sediment, decreased water level, loses steambed hab
Environmental: FF combustion during dam construction; increased evap due to larger surface area of reservoir
Economic impacts: humans homes and businesses must be relocated due to reservoir flossing
Initial construction is very expensive (does create long term jobs tho soo)
Potential loss of fishing revenue is salmon breeding is disrupted
Fish Ladders
Cement “steps” or series of pools that migratory fish like salmon can use to continue migration upstream, around or over dams
Enables continued breeding for salmon, food sources for predators like birds, bears, dishing for humans
Benefits of Hydrodams
No GHG emission when producing electricity (initial construction does require)
Jobs created to maintain dam
reservoir/dam can be tourist attractions
Reliable electricity source for nearby
No air pollutants
Control of downstream seasonal flooding (use for hydroelectricity, recreation/scenic, flood control)
6.10 Energy
Natural radioactive decay of elements deep in earth’s core gives of heat
Water piped down into ground, heated by this heat
Hot water converted into steam>KINETIC ENERGY OF STEAM TURNS turbine> electricity or to heat homes directly
The heat from magma turns water>steam which is forced through pipes to spin a turbine
Water is cooled in cooling tower and returned to the ground to start process over
Renewable b/c heat from earth’s core wont run out, only is groundwater is returned after use
Ground Source Heat Pump
“” but technically heat does not come from from geologic activity FROM GROUND STORING HEAT FROM SUN
10 ft down, ground stays consistent 50-60 degrees from holding heat from sun
Heat is absorbing fluid pumped through pipe into ground where it takes heat from ground (winter) or gives off heat into ground (in summer)
heating
Piping water deep into ground to be heated by magma and then transfering heat from water>building
1000s of meters into ground to reach heater water reservoir
PRO
Potentially renewable if water is piped back into ground for reuse
Much less CO2 emission than FF
No release of (PM/SO/NO/CO)
CON
Not everywhere has access to energy
Hydrogen sulfide can be released, lethal/toxic to humans and animals
Cost of drilling deep into earth can be high initially (sometimes not worth it)
6.11 Hydrogen Fuel Cells
Hydrogen Fuel Cell Basics
Hydrogen is a renewable, alternative fuel source to FF
H2 and O2 are inputs used to create electricity w H2O as waste product
H2 gas enters fuel cell, split into protons (H+)and electrons by electrolyte membrane that only allows for protons to pass
Electrons take alternative route around the membrane>creates electrical current
O2 molecule break apart and combine w 2 hydrogens to create H2O byproduct
VEHICLES: replaces gasoline with H fuel
Creating H2 Gas
Have to obtain pure H gas (doesnt exists by itself as a gas naturally)
Serapting H2 gas from other molecules like H2O or CH4 is energy intensive
Steam reforming: burning natural gas (CH4) and using steam to separate the H gas from methane
Emits CO2 and requires FF input
Electrolysis: electrical current is applied to water to break it into O2 and H2
No CO2 emission, requires electricity
PROS
Can be stored in pressurized tanks, easy transport for different locations (not like solar, hydro, wind where must be used as soon as generated)
Used as fuel for vehicles (replacing gasoline) or ammonia for fertilizer
Gasoline replacement> EMITS NO AIR POLLUTANTS, ONLY H2O
Many industrial chemicals requires H2 gas
Can be stored as liquid/gas, easy for transport
H fuel cells are 80% efficient in converting chemical energy in H2 and O2 ino energy
CONS
95% of H2 production requires methane (CH4), based on nonrenewable source and CO2 releasing energy source
H fuel stores in gas form in vehicles would require larger tanks than current gasoline tanks
Products H2 gas and Oxygen goes through first reaction layer into proteins/electrons
Electrons produce electric current while protons flow through a membrane layer, on the other side they are combined with oxygen from the environment to create water vapor as the product
6.12 Wind Energy
Wind Turbine Electricity Generation
Kinetic energy of wind spins turbine>generator converts mechanical energy of turbine >electricity
Avg wind turbine has 15-30% capacity factor of total possible energy it could generate
Location
Clustered in groups in flat, open areas (usually rural)
Locating them together makes service, repair, and building transmission lines to them easier
Can share land with agricultural use
Offshore wind= wind farms in oceans/lakes
PROS:
Capitalized on the faster wind speeds
Environmental: Less damage due to decreased reliance on fossil fuels (less habitat destruction since there is less need for extracting natural gas and oil)
Economic: Increased creation of jobs such as construction, operation, and maintenance of the offshore wind project
Can also be used for tidal power:as the tides come in, propellers could be placed underwater to make energy
CONS:
Requires transmission lines built across long distances to reach land
Benefits
Non-depletable
No GHG emissions or air pollutants released when generating electricity
No CO2 (climate change) or No/SO/PM
Can shae land use (doesnt destroy habitats or cause soil/water contamination)
Drawbacks
Intermittency (isn't always available)
Can kill birds and bats
Considered eyesore or source of noise pollution by some
6.13 Energy Conservation
Small Scale Energy Conservation
Lowering thermostat to use less heat/AC less often
Conserving water (native plants instead of grass, low flow shower heads)
Energy efficient appliances, better insulation to keep more heat home
Large Scale Energy Conservation
Improving fuel efficiency
Subsidizing (tax credits) for electric vehicles, charging stations, hybrids
Increased public transport
Green building designs
Sustainable home
Using passive solar design to trap heat and decrease energy from heatings system
Well insulated walls/attic trap heat in winter/cool air from AC in summer (decreases electricity used)
Water conservation
Native plants require less watering than traditional lawns (increases biodiversity of pollinators, less fertilizer)
Low-flow showers, toilets, dishwater use less total water
Rain barrels allow rain water to be used for watering plants/cras
Transportation
Improving fuel economy of US vehicles that conserve energy w less gasoline/diesel needed
CAFE (corporate average fuel economy) standards are set in US to require auto manufacturers to make cars that meet standards or pay penalties
Hybrids have gasoline + electric engine
Electric vehicles like tesla or LEAF use no gasoline, but still require electricity
Public transit & carpooling
Buildings
Green roof or walls decrease runoff, absorb sun’s heat = ;ess need for cooling building and surround area
Sun lights on roof can decrease electricity used for lighting
Recycled materials reduce energy required to produce new ones (glass, wood)
7.1 Air Pollution Basics
Clean Air Act (1970) identified 6 criteria air pollutants that the EPA is required to set acceptable limits for, monitor, and enforce
SO2 (sulfur dioxide): from coal combustion used for electricity OR naturally from coal and oil
Effects: respiratory irritant, smog, and acid precipitation
NO & NO2 (Nitrogen Oxides): fossil fuel combustion OR forest fires, lighting, soil microbes in nature
Effects: formation of O3, photochemical smog, acid precipitation
CO (carbon monoxide): incomplete combustion, vehicle exhaust ( manure, charcoal, kerosene)
Effects: O3, lethal to humans
PM (particulate matter):fossil fuel and biomass combustion
Effects: respiratory irritant and smog
PM2.5: greatest health concern; lodges deeply in respiratory tract>>usually more toxic
PM10: too small to be filtered by respiratory tract>>health concern
O3 (ozone troposphere): from the photochemical oxidation of NO2
Effects: respiratory irritation, formation of smog, damaging to plant stomata so it limits growth
Pb (lead): metal plants, waste incineration (gasoline, paint in older buildings, toys and jewelry, pipes)
Effects: neurotoxicant
Air Pollutants vs. Greenhouse Gasses
CO2 is NOT an air pollutant as part of the Clean Air Act
It does not directly lower air quality as it is not toxic to organisms to breathe, not damaging to lungs/eyes, and does not lead to smog/decreased visibility
CO2 is a GREENHOUSE GAS: it leads to earth warming and thus env and human health consequences
Use fire air pollutants on FRQS: SO2, NOx, O3, PM
Coal Combustion
Releases more air pollutants than other FFs: ~35% of global electricity
Releases CO, CO2, SO2, NOx toxic metals (mercury, arsenic, lead), and PM (often carries toxic metals
Impacts of SO2:
Respiratory irritants
sulfur aerosols block incoming sun=reduces visibility, photosynthesis
Forms sulfurous (grey) smog
Combines with water and O2 in atmosphere to form sulfuric acid>acid precipitation
Nitrogen Oxides (NOx)
Released by combustion of FFs and biomass (NO and NO2)
NO forms when N2 combines with O2 (like during combustion)
NO can become NO2 by reacting with O3 or O2
Sunlight converts NO2 back into NO
Env. and human health impacts:
Resp. irritants
Leads to tropospheric ozone (O3) formation>photochemical smog
Combines with water and O2 in atm. To form nitric acid>acid precip.
EPA and Lead
Vehicles made after 1974 are required to have catalytic converters to reduce NOx, CO, and hydrocarbon emissions (aka known as neurotoxicant-damages nervous systems of humans)
Primary vs. secondary air pollutant
Primary: Emitted directly from sources such as vehicles, power plants, factories, power plants, factories, or natural sources
NOx, CO, CO2**, VOCs, SO2, PM, hydrocarbons
Secondary: primary pollutants that have transformed in presence of sunlight, water, O2
Occur more during the day b/c sunlight usually drives formation
Tropospheric O3 (ozone), sulfuric acid (H2SO4) & sulfate (SO42-). Nitric acid (HNO3) & nitrate (NO3-), acid rain, photochemical smog,
7.2 Photochemical Smog
Secondary form of pollution forming when NOx chemicals mix with VOCs in sunlight forming other pollutants
NOx form in the morning and peak in the afternoon (occurs more often in summer when sunlight is at its peak
Water and oxygen in the atmosphere react with NOxs and form: Ozone; PANS (peroxyacyl nitrates, Acid Deposition
Precursors
NO2 is broken by sunlight into NO + O
Volatile organic compounds that bind with NO and form photochemical oxidants
Carbon-based compounds that evaporate easy
Sources: gasoline, formaldehydrade, cleaning fluids, oil-based paints
O3 forms when NO2 is broken by sunlight and free O binds to O2
Resp irr in troposphere
Damaging to plant stomata>limits growth
Conditions
Sunlight drives O3 formation by breaking down NO2> NO + O then free O atom binds to O2
Warm: hotter atm. Temp speeds O3 formation, evaporation of VOC and thus smog formation
Normal O3 formation
Sunlights breaks NO3> NO + O2
O binds with O2 to form O3
At night, O3 reacts with NO to form NO2 and O2, O3 levels drop overnight
O3 formation peaks in afternoon when sunlight is most direct and NO2 emissions from morning traffic have peaked
Morning commute>high NO2 levels from car exhaust
Photochemical Smog Formation
Sunlight breaks NO2> NO + O
O bonds with O2 to form O3
VOCs bonds with NO to form photochemical oxidants
Without NO to react with O3, builds up instead of returning to O2 and NO2 overnight
O3 combines with photochemical oxidants (NO + VOCs) to form photochemical smog
Factors that increase smog formation
More sunlight (summer, afternoon) = more O3
Warmer temp speeds evap of VOCs that lead to O3
Higher VOCs emissions (gas stations, laundromats, plastic factories, petrochem factories)
Increased vehicle traffic; increases NO2 emissions and therefore O3 formation
Impacts of Smog
Environmental: reduced sunlight>limits photosynthesis
O3 damages plant stomata and irritates animal resp tracts
Humans: resp irritant, worsens asthma, bronchitis, COPD, irritates eyes
Economic: increased health care costs to treat asthma, bronchitis, COPS
Lost productivity due to sick workers missing work or dying
Decreased ag. Yields due to less sunlight reaching crops and damage to plant stomasa
Reduction of SMOG
Vehicles: decreasing the # of vehicles on the road decreases NO2 emissions
Fewer vehicles = less gas= less VOCs
Carpooling, public transport, biking, walking, working from home
Energy: increased electricity production from renewable sources that don't emit NO (solar, wind, hydro)
Nat gas power plants release for less NO than coal
7.3 Thermal Inversion
Urban Heat Island Effect
Urban areas tend to have higher surface and air temp than surrounding suburban and rural areas due to:
Lower albedo: concrete and asphalt absorb more of sun’s energy than areas with more vegetation (absorbed sunlight is given off as IR radiation-heat)
Snow is higher albedo>keeps cooler
Less evapotranspiration: water evaporating from surfaces and transportation from surfaces and transpiration from plants carries heats from surface into the atmosphere
This cools off rural and suburban areas which have more vegetation
Thermal Inversion
NORMALLY, the atmosphere is warmest at earth’s surface and cools as altitude rises
Warm air rises> air convection carries air pollutants away from earth's surface and distributes them into higher into the atmosphere
During thermal inversion>> cooler air mass becomes trapped near earth's surface
Due to warm front OR due to hot urban surfaces coling overnight whole IR radiation absorbed during day is still being released
CITIES MOST PRONE DURING WINTER: HAVE TO BE FAR ENOUGH N/S TO HAVE DISTINCT WINTER
Cold air at the surface is trapped beneath the warmer mass above, convection doesnt carry pollutants up and away
Effects of Thermal Inversion
Air pollutants (smog, PM, ozone, SO2, NO2, PM10, PM2.5, Woodsmoke) trapped closer to earth
Respiratory irritation: asthma flare ups>hospitalization, worsened COPD, emphysema
Decreased tourism revenue
Decreased photosynthetic rate
Regulations
Increased public transportation
Limited vehicle permits
Emission testing for personal and commercial vehicles
Restrictions on agricultural burning, waste-burning, coal-burning power plants
Educational and incentive programs
Los Angeles is a highly populated city with much car traffic. It also sits next to the Pacific Ocean and receives cool prevailing winds that are trapped by nearby mountains. This cool air is much denser in comparison to the hot surface air found over the land. As a result, the cool air sinks below the warm air.
7.4 Atmospheric CO2 and PM
Natural Sources of Air Pollutants
Lightning strikes: convert N2 in atm. to NO
Forest fires: CO, PM, NO
Combustion of biomass also releases CO2 and H20 vapor
Plasts (esp conifers): plants emit VOC
Volcanoes: SO2, PM, CO, NO
Natural Sources of CO2 and PM
Respiration: all living things release CO2 through respiration
Natural PM sources: sea salt, pollen, ash from forest fires and volcano dust
Leads to haze
Aerobic decomposition: decomposition of organic matter by bacteria and decomposers in the presence of oxygen>> releases CO2
Anaerobic decomposition: decomposition of organic matter by bacteria and decomposers in low or oxygen -free conditions> releases CH4/methane
PM10 vs PM2.5
Particulate matter: solid or liquid particles suspended in air
PM10 (<10 micrometers)
Particles or droplets like dust, pollen, ash, mold
Too small to be filtered by nose hairs and trachea cilia
Nose hairs and mucous secretions in our nose and throat trap larger particles and prevent larger particles from getting to our lungs
Can irritate respiratory tract and cause inflammation
PM2.5 (<2.5 micrometers)
Particles from combustion (esp vehicles) smaller dust particles
Most likely to travel deep into the lungs due to smaller size
Associated with chronic bronchitis and increased risk of lung cancer
7.5 Indoor Air Pollutants
Developing vs. Developed Countries
Developing nations use more subsistence fuels like wood, manure, charcoal
Release CO, PM, NOx, VOCs, cause deforestation
Often combusted indoors with poor ventilation=high concentrations
Developed nations use more commercial fuels (coal, oil, natural gas) supplies by utilities
Typically burned in closed, well ventilated furnaces, stoves, etc
Major indoor air pollutants come from chemicals in products; adhesives in furniture; cleaning supplies; insulation; lead paint
PM & Asbestos
Particulates are a common indoor air pollutant (ex. Smoke, dust, asbestos)
Asbestos is a long, silicate particle previously used in insulation (linked to lung cancer & asbestosis)
Out of use but remains in older buildings
Not dangerous until insulation is disturbed and asbestos particles enter air & resp tract
Should be removed by trained professionals with proper respiratory equipment, ventilation in area its being removed from, plastic to seal off area from rest of building
CO (Carbon Monoxide)
Produced by incomplete combustion of any fuel (not all fuel combusted w low O2 or temp)
CO is an asphyxiant: causes suffocation due to CO binding to hemoglobin in blood, displacing O2
Lethal to human in high concentrations, esp with poor ventilation (odorless/colorless)
Developed nations: CO released into home by malfunctioning natural gas furnace ventilation (detected by carbon monoxide detectors)
Developing nations: CO emitted from indoor biomass combustion for heating/cooking
VOCs (volatile organic compounds)
Compounds or molecules that vaporize and become airborne at low temperatures
MUST CONTAIN CARBON
Chemicals used in variety of home products that easily vaporize, enter air, irritate yes, lungs, bronchioles
Natural VOC: volcanoes/forest fires release benzene
adhesives/sealants: chemicals used to glue carpet down, hold furniture together, seal panels
Formaldehyde is a common adhesive in particle board and carpet glues
Cleaners: common household cleaners and deodorizers like febreeze
Plastics and fabrics: both can release VOCs or from adhesives used in production
Radon Gas
Radioactive gas released by decay of uranium naturally found in rocks underground (esp granite)
Usually enters homes through cracks in foundation, disperses up from basement/foundation through home
Can seep into groundwater sources + enter body through drinking water
2nd leading cause of lung cancer after smoking
EPA recommends testing homes with airborne radon monitor
Sealing cracks in foundation can prevent it from entering/increasing ventilation in home can disperse if its detected
Dust and Mold
Natural indoor air pollutant that can worsen asthma, bronchitis, COPD, emphysema
Dust settles in homes naturally, distrubed by movement, enters air and then resp tract
Mold develops in dark, damp areas that aren't well ventilated
Black mold releases spores into air; harmful to resp. system
Can be removed physically cleaning mold out + fixing water leak/ventilation issue that led to mold formation
Lead
Found in paint in old homes (EPA banned lead paint in 1978)
Paint chips off walls/windows and is eaten by children or inhaled as dust
Lead water pipes also release lead into drinking water sources, less common than lead paint
Damages central nervous system of children due to smaller size + developing brain
Can be removed by strippnig lead paint, replacing with non-lead based paint; lead water pipes replaced with copper pipes
7.6 Reduction of Air Pollutants
Reducing emissions=reducing air pollutants
Drive less, walk/bike/bus more
Conserve electricity (smart appliances)
Eat more plants, less meat
Renewable, non-pollution emitting energy
Laws/Regulation
Clean Air Act: allows EPA to set acceptable levels for criteria air pollutants
Monitor emission levels from power plants and other facilities
tax/sue/fine corporation that release emissions above levels
CAFE Vehicle standards: (corporate average fuel economy) standards require the entire US fleet of vehicles to meet certain average fuel
Requires vehicle manufacturers to work to make more efficient vehicles
More efficient vehicles burn less gasoline and release less NOx, PM, CO, CO2
Pollutant Credits: similar to ITQs for fish
Companies that reduce emissions well below EPA-set levels earn pollution credits
They can sell these to companies that release more than acceptable levels
Reducing Vehicle Air Pollutant
Vapor Recovery Nozzle: captures hydrocarbon VOCs released from gasoline fumes during refueling
Separate tube inside nozzle captures vapors, returns them to underground storage tank beneath gas station
Reduces VOCS(reduce smog, resp irritants), benzene (carcinogen)
Catalytic Converter: required on all vehicles after 1975
Contains metals (platinum & palladium) that binds to CO & NOx & hydrocarbons to convert into CO2, N2, O2, H2O
Reducing SOx & NOx
Crushed Limestone (SO2): used to reduce SO2 from coal power plants
Crushed coal mixed w limestone before burned in boiler
Calcium carbonate in limestone + SO2 = calcium sulfate >reduced SO2 emitted
Used for gypsum wallboard or sheetrock 4 home foundations
Fluidized Bed Combustion (NOx): fluidizing jets of air pumped into combustion bed
Jets of air bring more O2 making combustion more efficient + bringing more SO2 into contact w calcium carbonate in limestone
Allows coal to be combusted at lower temp>emits less NOx
Wet & Dry Scrubbers
Dry Scrubbers (NOx, SOx, VOCs): large column/pipe w chemicals that absorb or neutralize oxides (NOx, SOx, VOCs) from exhaust streams
Calcium oxide is a common dry scrubber additive, reacts w SO2 to form calcium sulfite
Wet Scrubbers (NOx, SOx, VOCs, PM): involves chemical agents that absorb or neutralize NOx, SOx,VOCs, mist nozzles that trap PM in water droplets
Mist droplets with pollutants and PM trapped in fall to bottom of scrubber or get trapped @ top by mist eliminator
Sludge collection system traps polluted water for disposal
Reducing PM
Electrostatic Precipitator: power plant/factory emissions passed through device with a neg. charged electrode gives particles a neg charge
Neg. charged particles stick to pos charged collection plates, trapping them
Plates discharged occasionally so particles fall down into collection hopper for disposal in landfills
Baghouse Filter (PM): large fabric bag filters that trap PM as air from combustion/industrial processes pass through
Shaker device knocks trapped particles loose into collection hopper below
PM collected & taken to landfill
Difference between “good” ozone and “bad” ozone
Function of the ozone layer?
To absorb the sun’s harmful UV rays, allowing just enough for life on earth
Ozone Layer Formation
Step 1: O2 + ultraviolet rays = O + O
Step 2: O + O2 = O3
CFCs:
Chlorofluorocarbons
Nontoxic, nonflammable
Contain C, Cl, F
Found in refrigerants, propellants (aerosols), foam, and packing materials
UV causes a chlorine atom to break away from the CFC molecule
Free chlorine atom hits an ozone molecule
The chlorine atom pulls 1 oxygen atom away
A free oxygen atom hits the chlorine monoxide molecule
Results in another free chlorine atom
Free chlorine will continue to deplete ozone in the stratosphere
Montreal protocol: limited/banned CFCs in many countries
7.7 Acid Rain
Sources of NOx & SO2
SO2: coal fired power plants. Metal factories, vehicles that burn diesel fuel
NOx: vehicle emissions, diesel generators, coal power plants
Limiting Acid Rain (decreased after clean air act)
Reducing NOx & SO2 emissions reduce acid deposition
Higher CAFE standards
More public transit
Renewable energy sources
More efficient electricity use
NOx & SO2 react with O2 and H20 in the atmosphere, forming nitric and sulfuric acid
Sulfuric acid and nitric acid dissociate in the presence of water into sulfates and nitrate ions and hydrogen ions (H+)
Acidic rain water (higher H+ conc) decreases soil and water pH
Limits tree growth in forests down wind from major SO2 and NOx sources
Env. effects of Acid Rain
acidity= higher H+ ion concentration, lower pH
soil/water acidification:
H+ ions displace or leech other pos. Charge nutrients (Ca2+, K+) from soil
H+ ions make toxic metals like aluminium & mercury more soluble in soil and water
Slows growth or kills plants and animals living in the soil or water
pH tolerance:
As pH decreases outside optimal range for species, pop. declines
When pH leaves range of tolerance, they cannot survive due to aluminium toxicity, disrupted blood osmolarity (Na+/Cl- balance disrupted at low pH)
Indicator species can be used to determine conditions of an ecosystem (soil, water, etc.)
Mitigating Acid Rain
Limestone (calcium carbonate) is a natural base to neutralize acidic soil/water
Limestone: calcium carbonate reacts with H+ ions = HCO3 + Ca 2+
Neutralizes acidic water/soil, moving pH closer to 7
Regions with limestone bedrock have natural buffering of acid rain (humans can also add crushed limestone to soils/waters to neutralize)
Acid rain can corrode human structures, esp made of limestone
Limiting SO2 & NOx: decreasing primary pollutants that drive acid rain to reduce
Renewable energy sources, decreasing coal comb; fluidized bed combustion & lower burning temp. For existing coal power plants; dry or wet scrubbers
7.8 Noise Pollution
Urban noise pollution: any noise at great enough volume to cause physiological stress(dif hearing, headaches, confusion) or hearing loss
Construction: jack hammers, trucks, concrete pouring
Transportation: cars, buses, trains
Industrial activity: manufacturing plants
Domestic activity: neighbor’s music, lawn mowing, home projects
Wildlife Effects (land)
Noise pollution can disrupt animal communication, migration, and damage hearing
Physiological stress: caterpillar hearts beat faster when exposed to stimu;ated highway noise pollution
Could drive pollinator species decline
Hearing: can prevent predators from hearing prey and vice versa; can prevent mats from locating each other (decreases chances of survival)
Wildlife Effects (aquatic)
Aquatic noise pollution comes from the noise of ship engines, military sonar, and seismic air blasts from oil and gas surveying ship
Physiological stress: hearing loss, disrupted communication, mating calls, predator and prey navigation
Whales are especially prone to having migration routes disputed as vocal communication is disrupted
animals that rely on sonar or sound for navigation, feeding and communication can be disoriented by mechanical sounds and sonar used by humans.
Seismic surveying: ships send huga air blasts down into the water, searching for oil by recording how the echo is returned from ocean floor
So loud that researchers off the coast of virginia cn detect blasts from coast of brazil
Explain one way that you can modify this procedure to better determine the impact of fossil fuel combustion on sulfur dioxide levels.
Maybe burn some coal: lignite, bituminous, and anthracite to allow for a wider variety as coal is a fossil fuel, and the combustion of coal is an anthropogenic source of sulfur dioxide which will allow to make better conclusions
Adjust the temperature the fossil fuels are being burned
Change volume of the burning
Locations with the highest levels of tropospheric ozone? Dallas, Texas because it is bright/sunny
Describe the relationship between the max daily temperature and max daily ground level ozone that is shown by this data
As the maximum ground level ozone increases, the temperature increases as a exponential relationship
a. Describe the trend that you observe in the figure between altitude B and C
Between B and C, the altitude is increasing as the temperature is increasing positively in which the directionality is different from before and after
B. Identify one pollutant that would increase in concentration due to the temperature anomaly between B and C.
One pollutant that would increase in concentration would be tropospheric ozone, O3,
c. explain how the trend you obsessed in a could lead to increased effects of the pollution you identified in b
There is a temperature inversion occurring in which the trend is going against the normal trend of temperature decreasing with the increasing altitude. The thermal inversion traps pollution closer to the ground and as the cold air is trapped beneath the warmer mass above, the convection does not carry the pollutants away
a. Explain the method that will be used to collect and analyze data
To collect particulate matter density, a card wi
b. Describe the variables in the investigation
The independent variable is; how will it be manipulated?
The dependent variable is; how will it be measured
c. describe the factors that will be controlled in the study
What are being constant and why