APES Units 1-7

SO₂

Sulfur Dioxide. Corrosive, comes from coal + oil combustion. Precursor to acid rain/acid deposition.

NO_x

Nitric oxide (NO) and nitrogen dioxide (NO₂). Comes from all combustion. Irritant, tropospheric O₃ precursor, can convert into nitric acid → harmful to marine life.

CO

Carbon monoxide. Asphyxiant → death if exposed too much. Comes from bad exhaust, incomplete combustion, poor ventillation w/ combustion.

PM

Particulate Matter. Comes from biofuel + biomass combustion + certain activities. Reduces visibility, exasperates respiratory issues + cardiovascular issues + cancer.

O₃

Ozone. Secondary pollutant when in the troposphere. Degrades plant surfaces, reduces lung function, + damages materials (ex: rubber + plastic).

Pb

Lead. Used to be a gas additive. Impairs central nervous system + impairs ability to learn/concentrate.

Clean Air Act

Required lead to be phased out as a gas additive between 1975-1996. In 2021 no lead in gasoline anywhere.

Secondary Air Pollutants

Pollutants that have undergone transformation in sun, water, or air. Caused by primary pollutants → into secondary pollutants.

Ozone is the major one!! Formed from NO_x + VOCs

Photochemical Smog

Polluted orangey-brown haze formed by sunlight driven chemical reactions.

NO_x + VOCs → O₃ + PANs (family of smog chemicals, stable in cool air so travel long distances)

Irritates eyes + throat + triggers coughing + asthma. PANs = acute tissue irritant esp for plants. O₃ reduced photosynthesis.

Reducing Photochemical Smog

Reduce vehicle use, use EVs, vapor recovery nozzle at gas stations

Catalytic converter: VOCs, NO_x, CO → N₂, H₂O, O₂, CO₂

Thermal Inversions

Ground cools rapidly at night → air near surface cools, becomes dense, + sinks.

Warmer layer of air above (often strengthened by sinking, warning air in high pressure systems) prevents vertical mixing.

Pollutants get trapped near ground → more smog

PM₁₀ vs PM_2.5

Larger than PM₁₀ (10mm) usually filtered by nose + throat, but PM₁₀ and less are not.

PM_2.5 even more of a concern because they travel further + can be composed of more toxic material.

Radon

Naturally occurring radioactive gas, comes from decay of uranium in rocks + soil. Can enter home through cracks in foundation. Exposure can lead to cancer (2nd leading cause of lung cancer, after smoking).

VOCs

Found in many building materials, furniture, glues, paints, detergents, cleaners, air fresheners Formaldehyde is one of the most toxic (common in new homes, found in particle board and carpeting glue) + is carcinogenic.

Can cause burning sensations in eyes and throat, + breathing difficulties and asthma

Sick Building Syndrome

A buildup of toxic pollutants in weatherized newer buildings containing synthetic materials (most common in office buildings).

Crushed Limestone

Combines w/ SO₂ to make calcium sulfate, reducing SO₂ emissions. Calcium sulfate can be used for gypsum wall board or for foundations.

Dry Scrubbers

Big column w/ chemical that absorbs/neutralizes NO_x, SO₂, + VOCs. Often calcium oxide because calcium oxide + SO₂ → calcium sulfite

Wet Scrubbers

Chemicals + mist nozzles trap PM in water, mist falls to the bottom or gets trapped at top, sludge collection systems → dispose of polluted water.

Fluidized Bed Combustion

Jets of oxygen make combustion more effiecent + bring SO₂ into contact w/ more crushed limestone + reduce temps (reduce NO_x)

Acid Depostion

Process where acidic pollutants from the atmosphere fall to Earth’s surface in wet (rain, fog, snow) or dry (dust, gas) form.

Primarily caused by burning fossil fuels. Acidifies bodies of water, harms wildlife, and corrodes buildings + man-made structures

 NOx + SO₂

Primary pollutants that cause acid deposition. Both react w/ O₂ and water in the atmosphere.

SO₂ - produced mostly from coal fired power plants, sulfuric acid.

NO_x -  produced mostly from vehicle emissions and coal power plants, nitric acid.

Decreases pH (increases acidity) of soil + water.

Limestone

Calcium carbonate. A natural base that can neutralize acidic soil/water. Regions w/ this as bedrock have some natural buffering of acid rain. Can also be added to neutralize acid.

Nonrenewable Energy Sources

Exist in fixed amounts that cannot be replaced.

Examples: nuclear (uranium is a finite resourced), fossil fuels

Renewable Energy Sources

Can be replenished naturally at or near rate of consumption + reused. If managed correctly can be used indefinitely.

Examples: hydroelectric, solar, wind, waves, geothermal, + biomass (wood, cow dung, + corn used for biofuel)

Wood and Charcoal

Primarily used in developing countries for heating and cooking.

Removal of trees → soil erosion/degradation, deforestation can decrease amount of precipitation bc disrupting water cycle (?) + decreased CO₂ sequestration, if used indoors w/out proper ventilation indoor air pollutants released

Peat

Partially decomposed organic material, including moss that can be burned for fuel. Is a precursor to coal. Can also cause indoor air pollution.

Coal

Electricity + industrial processes. Formed from peat + takes hundreds of millions of years to form. 3 types of coal based on age, exposure to heat/pressure, + depth.

Greater moisture content = more smoke + less efficient

Greater sulfur content = more acid deposition (acid rain formation)

Levels of Coal

Peat (not coal) → Lignite → Bituminous → Anthracite

Further left the more heat + pressure. Anthracite is most desirable because low sulfur/most pure. Bituminous is most used because of it’s availability, has high sulfur content.

Natural Gas

Used for electricity + industrial processes. Some homes use it for heating/cooking/hot water heaters. Is is largest user. Composed mostly of CH₄ (80-95%).

Considered the “cleanest” fossil fuel bc produces smaller amounts of particulates, SO₂, and CO₂ (compared to coal or oil), but still produces CO₂

Crude Oil

Naturally occurring unrefined petroleum found underground + in tar sands. Can be refined into gas, diesel fuel, or jet fuel. Also for heating oil + asphalt.

Refined based on different boiling points!

Tar Sands

Slow flowing, viscous deposits of bitumen (asphalt) mixed w/ sand, water, + clay. Crude oil an be extracted w/ surface mining.

Extracting has very neg results (destroys ecosystems, creates large open pits, contaminates watersheds + aquatic life). Extracting process also very energy intensive.

Cogeneration

Use of fuel to generate electricity + deliver head to building or industrial process.

By capturing heat usually lost, power plants achieve up to 90% efficiency compared to 35-75% for separate systems

Fossil Fuels in Sedimentary Rocks

Source Rock (D) - Organic matter subjected to heat + pressure over time → oil and gas which collects in reservoir above

Reservoir Rock (C) - Porus, permeable rock that holds oil + natural gas that has migrated from below

Caprock (B) - Impermeable rock that prevents the oil + natural gas from migrating to the surface (rock can still be proud but holes may not be connected)

Combustion

Chemical process. Fuel + O₂ → CO₂ + H₂O

Process of Coal into Energy

• Coal pulverized

• Coal burned

• Heat from combustion turns water to steam

• Steam turns turbine

• Turbine turns a generator

• Generator generates electricity

Fracking

Hydraulic fracturing. Process to remove natural gas from rock.

• well is drilled in the ground (lined w/ clay or ceramic to prevent groundwater contamination)

• pipe inserted into well to extract natty gas

• fracking fluid (water w/ sand + volatile chemicals) is pumped into pipe, fluid breaks the rock holding natty gas

• Natural gas trapped in rock escapes + piped out

Environmental Impacts of Fracking

• creation of well → habitat destruction + water contamination

• pipe not lined properly → fracking fluid contaminates groundwater

• fracking fluid contains VOCs, can contaminate groundwater + end up in atmosphere

• natty gas may leak out into atmosphere + groundwater

• uses a lot of water + creates waste water

• can cause earthquakes (breaks rocks) → can cause pipe to crack → natty gas and/or VOCs escape

Nuclear Energy

Advantages: no CO₂ emissions, no air pollution, way to achieve energy independence from fossil fuel imports, small land footprint compared to solar + wind

Disadvantages: nuke waste management, $$$ + time consuming to build nuke plants, uranium-235 technically nonrenewable, risk of accidents

Parts of a Nuclear Power Plant

Heat from nuke fission used to heat water vapor to steam → turns turbine.

Control rods - between fuel rods, absorb excess neutrons to prevent meltdown

Cooling towers - stereotypical nuke plant symbol, used to cool + release water vapor

Condenser - turns steam back into liquid water

Biofuels

Liquid fuels created from processed or refined biomass.

Usually ethanol or biodiesel.

Ethanol

Alcohol make by converting starches + sugars from plant material into alcohol + CO₂. 90% made in the US comes from corn. Actually probably worse for the environment than regular gas because of the land required + all that, but less directly worse.

Biodiesel

Diesel substitute produced by extracting + altering oil from plants.

Passive Solar

Taking advantage of energy from the sun w/out active technology. Cannot be stored, used when received. Ex: house set up so it receives sunlight that heats it in the morning, ect.

Active Solar

Technologies that capture + store energy of sunlight w/ electrical equipment.

Solar water heating system - pipe of cold water goes to roof where heated up + goes to hot water tank

Photovoltaic systems

Benefits: no CO₂ or pollutants, produced energy on peak demand days (hot + sunny), can be economically feasible on small scale

Drawbacks: photovoltaic cells are expensive to make + initial cost is high, manufacturing needs fossil fuels

Photovoltaic System

Photovoltaic cells capture energy from the sun as light, not heat, + convert it directly to electricity. Can directly be used for highway signs, emergency telephones, smart parking meters, + more.

Concentrates Solar Thermal Electricity Generation

Aka CST systems, they’re large scale + similar to convention power plants but energy from from the sun is used to heat water into steam.

Hydroelectric

Kinetic energy of moving water can be transformed into electricity.

• Water stored in a reservoir has potential energy

• As water moves through the dam, stored energy is converted into kinetic energy

• Kinetic energy of water converts to mechanical kinetic energy of spinning turbine 

• Spinning turbine causes a generator to turn

• Mechanical kinetic energy of turbine is converted to electrical energy from the generator

• Electricity flows from the dam to the grid

Same principle applies to tidal energy.

Fish Ladders

Provide a way for salmon to make up up + over a dam to swim upstream.

Advantages of Hydro-Power

• No air pollution

• No waste

• Relatively inexpensive electricity generation

• Additional services provided by reservoir (recreation like fishing and boating, can provide irrigation water for agriculture or drinking water for people)

Disadvantages of Hydro-Power

• Flooding of land for reservoir

• Disruption to flow rates of river

• High maintenance cost for tidal power

• High construction costs for dams

• Most viable sites are already used

Geothermal Process

• Water is pumped down an injection well 

• Stored heat from the Earth’s interior turns the water into steam

• Steam rises from the production well

• Kinetic energy of the steam turns a turbine

• The turbine turns a generator

• The generator produces electricity

Advantages of Geothermal

• No CO₂ emissions

• not dependent on weather

• reliable + abundant (in some places)

Disadvantages of Geothermal

• limited areas where geo is cheap + efficient

• produces hydrogen sulfide gas pollution while drilling

• can impact groundwater

• implementation requires high up-front cost + costs electricity to run pumps

Wind Energy

Kinetic energy of moving air → kinetic energy of spinning turbine, kinetic energy in generator → electricity

Benefits: renewable, allows for multiple land uses

Drawbacks: birds + bats can be hit, locations must have consistent wind for constant power → backup generators needed for not windy days

Xeriscaping

Matching plants you plant to local environment, saves energy needed to water + take care of them bc they’re already built for the area.

Conserving Energy at Home

• shorter showers

• adjust thermostat

• energy efficient appliances

Conserving Energy in Transport

• carpool

• use EVs + hybrids

• public transit

CAFE

Corporate Average Fuel Economy Standards. Made car mpg more efficient.

Percent Change Equation

% change = (X2 - X1)/X1 = (new - old)/old

Green Building Design Features

• passive design elements (passive solar, windows facing sun, ect)

• insulation

• lighting from the sun

Hydrogen Fuel Cells

H₂ + O₂ → H₂O + electricity

Hydrogen atoms separate into protons + electrons by membrane + electrons forced to use an alt route → generates the electrical current.

Not a lot of H₂ available for refueling yet, but no air pollutants released.

4 Types of Forests

Tropical - hot year-round w/ high rainfall + most biodiverse

Boreal - found in high attitudes, dominated by conifers

Temperate - occur in places w/ distinct seasons, mix of deciduos and conifers

Subtropical - occur just N and S of the tropics, also a mix of trees

Provisioning Services of Forests

Lumber, paper, fuel

Cultural Services of Forests

Recreation (camping, hiking, ect), aesthetics, ecotourism.

Regulating Services of Forests

Storage of atmospheric carbon, purifies water + air, stabilize soil + reduce erosion, influences local/regional climate (provides shade + reflects light due to high albedo).

Supporting Services of Forests

Provides habitat, nutrient cycling, photosynthesis, water cycling.

Tragedy of the Commons

The tendency for a shared, limited resource to become depleted if it’s not regulated in some way.

Only applies to public commons.

Land or resource must become degraded or depleted.

Clear Cutting

Removing most or all trees from an area (can be combines w/ replanting so all the trees that regrow are the same age). Leads to deforestation, increases erosion from wind and water (esp. on slopes → higher change of landslides) which adds silt/sediment to nearby streams, increasing turbidity.

Tilling

Turns compacted soil to prepare for planting seeds.

Benefits: loosens soil allowing aeration and drainage, chops up existing weeds, helps mix compost + fertilizers into the soil.

Drawbacks: reveals bare soil → erosion, kills beneficial bacteria → reduced soil nutrients, releases stored CO₂, requires burning fossil fuels

Slash + Burn Agriculture

Occurs in developing countries w/ subsistence farming. Typically in tropical forests w/ low nutrient soil.

Drawbacks: unsustainable (ash nutrients only remain for a few years) → have to keep slash + burning new plots, releases CO₂ because combustion

Synthetic Fertilizers

Synthesized in large industrial plants (which requires fossil fuels).

Benefits: easy to transport + use, time released, customized for the soil’s specific needs

Drawbacks: production → CO_2, water soluble so enters runoff → eutrophication, often overused, does nothing for soil texture

Organic Fertilizers

Manure, compost, bone meal or fish emulsion.

Benefits: working into soil so stay put (less runoff concern), improve soil texture

Drawbacks: must be gathered (labor intensive process), nutrient levels unknown, harder to use (needs to be worked into soil)

Furrow Irrigation

Trenches built on either side of crops + filled with water. Oldest technique.

Pros: high sediment water can be used, allows for some precision of aplication

Cons: not efficient w/ sandy soil because it just passed through, most inefficient method (33% lost to evaporation + runoff), soil erosion occurs, waterlogging + salinization

Flood Irrigation

Lake or stream diverted to agricultural field, entire field flooded + water soaks in evenly, levee needed to retain water.

Pros: easy + inexpensive

Cons: requires body of water, not for all crops (usually is for rice), land but be graded (sloped + leveled), levees needed, inefficient (20% lost to evaporation), waterlogging + salinization can occur

Spray Irrigation

Pumps are used to spray from a nozzle directly on crops.

Pros: precision application, can be efficient (5%-25% lost to evaporation), can be programmed to run at certain times of day

Cons: larger up-front cost, probably included machinery (CO₂ emissions), nozzles can clog, pivot systems can wear ruts into soil

Drip Irrigation

Uses piped w/ micropores that drip water onto crops.

Pros: very efficient (5% evaporation), reduced nutrient leaching, no land grading needed, good for sandy soil

Cons: very expensive, micropores can clog, ones pipes are put down they’re difficult to move + vulnerable to punctures

Waterlogging

Pore spaces in soil required for plant roots, pore spaces provide O₂ to roots for cellular respiration, waterlogging results in death of roots → kills plants.

To remediate, allow soil to dry out + add sand.

Salinization

Freshwater has trace salts, after irrigation water evaporates salts build up in soil, most crops have low salt tolerance so salt kills plants.

Most likely to occur w/ furrow irrigation in warm areas with lots of sunlight.

To remediate, flush soil w/ lots of water

Depleted Aquifers

Overuse of irrigation can lead to depleted aquifers.

Persistent Pesticides

Remains in the environment for years or decades.

Problematic Pesticides

Can be transported through wind, runoff, and groundwater recharge. Can contaminate makes, streams, groundwater, and well water. Can result in killing of non-targeted species through bioaccumulation and biomagnification.

GMOs

Genetically Modified Organisms. Involve taking an adventurous gene from one organism and inserting it into the genome of another.

Ex: Bt corn that had a gene from a type of soil bacteria that naturally produces a toxin that kills insect larvae.

Meat Production lack of Efficency

Beef requires more than 80x as much land as wheat and 20x-30x more land than poultry or farmed fish.

Land requirements: land the animal occupies, land to provide food for animal to eat, land for disposal of waste

Meat Production Greenhouse Gases

CO₂ → mechanization

CH₄ - produced by cow’s digestive process + manure decomp

N₂O - produced from nitrification + denitrification of manure

CAFOs / Concentrated Animal Feeding Operations

Large indoor/outdoor structures designed for max occupancy of animals and max output of meat. Used for beef + dairy cows, hogs, + poultry. Animals have very little space.

Benefits: less land usage, feeding is more efficient, profits increased → fatter animals because less movement + fed high calories grains

Drawbacks: ethical concerns, high antibiotic use to curb outbreaks because they’re in a very concentrated space → antibiotic resistance, growth hormones, high water usage (cleaning + hydration), increased animal runoff + need for waste disposal

Manure Lagoon

Large human made pond lined w/ rubber to prevent leaking into groundwater. Used by large CAFOs, bacteria used to break down waste like sewage treatment plants, manure used as fertilizer.

Risks: produces a lot of N₂O, leaks in liner = groundwater contamination, can overflow into bodies of water, can lead to disease

Free Range Grazing

Allowing animals to graze outdoors on grass for most/all of life.

Benefits: more sustainable, less antibiotic use needed (animals more spread out), less fossil fuels used to make food cause animals eat the grass, waste is dispersed on it’s own, grazing can maintain grasslands

Drawbacks: uses more land, cost of meat is higher, overgrazing can occur if not managed correctly

Overgrazing

Excessive grazing in one area that can reduce or remove vegetation. Erodes + compacts soil. Arid environments w/ nutrient poor soils especially prone .

Desertification

Transformation of arable, productive, low precipitation land to desert-like unproductive land. Caused by climate change, overgrazing, + logging.

Nomadic Grazing

Sustainable solution to overgrazing. Farmers move herd of animals over long distances to seasonally productive feeding grounds.

Most sustainable way to graze animals, vegetation has time to regenerate, mimics natural grazing cycles of bison and wildebeests.

Rotational grazing

Cycling of livestock around a particular part of pasture to not overgraze an area.

Fishery

Commercially harvestable pop of fish w/in a particular ecological region.

Tragedy of the commons particularly applicable.

Fishery Collapse

When a fishery declines by 90% or more.

Commercial fishing methods

• Purse Seine Nets

• Bottom Trawling

• Gill Nets

• Long Line Fishing

• Pole + Line fishing

• Dredging

• Traps + Pots

Purse Seine Nets

Used to capture a school of fish often spotted w/ sonar or planes. Massive nets result in overfishing + bycatch.

Bottom Trawling

Nets are towed that drag across the seafloor to catch species that live on/near seafloor. Results in habitat destruction, esp in fragile ecosystems like grass meadows, sponge gardens, + coral reefs.

Sonar in Fishing

Pros: more efficient + profitable

Cons: overfishing + can interfere w/ behavior of marine species

Gill Nets

Set up to capture any fish that swim into them so result in a high amount of bycatch. Non-target species like turtles get caught.

Long Line Fishing

Lines can be over a mile long. Can result in overfishing.

Birds, turtles, + marine mammals also get caught on lines + hooks.

Pole + Line Fishing

The classing guy w/ fishing rod. Least environmental + ecological impact.