Unit 7 APES

Unit 7.1: Introduction to Air Pollution

Air Pollution - anything in the atmosphere that is harmful to humans or the environment

Primary Pollutants are emitted directly into the atmosphere

Natural: pollen, volcanic ash, VOCs given off by planes

Anthropogenic: products of combustion of fossil fuels (CO2, NOx, SO2)

Secondary Pollutants form once they are in the atmosphere, usually combining with water vapor or other atmospheric gasses

Examples: Ozone, acid rain

Clean Air Act

Passed in 1963, National Ambient Air Quality Standards came in 1970

Has been effective in reducing criteria air pollutants

Six pollutants deemed most harmful to human health

Sulfur dioxide (SO2)

Particulate matter (PM)

Lead (Pb)

Ozone (O3)

Nitrogen dioxide (NO2)

Carbon monoxide (CO)

Lead was a gasoline additive in the 1920s

Low Level Lead Exposure Health Impacts

Children

Anemia

Behavioral disorders

Lowered IQ

Reading and learning disabilities

Nerve Damage

Adults

Hypertension

Cardiovascular disease

Combustion of Fossil Fuels Releases Carbon

Combustion of fossil fuels releases the energy stored during photosynthesis (remember glucose = C6H12O6)

All fossil fuels contain carbon and hydrogen

Combustion of carbon creates carbon dioxide (CO2)

This carbon has not been in the atmosphere for millions of years

Coal contains many other elements absorbed by plants during their life or trapped in the sediments along with the organic matter

These impurities are also released during combustion

Specific elements vary by region

Combustion of coal creates pollutants of

Carbon dioxide

Sulfur dioxide

Heavy metals

Particulates

Formation of Coal

Plant matter -> peat -> lignite -> bituminous -> anthracite

Impurities in Coal

Impurities in coal are released during combustion

Sulfur -> sulfur dioxide (SO2)

Mainly present when coal is formed from marine biomes

Sulfur dioxide

Toxic Metals

Lead

Mercury

Nickel

Arsenic

Partially combusted “soot”

Particulate matter

PM carries many of the metals and heavier elements into lungs

Sulfur in Fossil Fuels

Sulfur is present in larger quantities in marine fossil fuels

Coal burning power plants can use filters and clean coal processing to decrease sulfur dioxide emissions

Crude oil (petroleum) also contains sulfur

Diesel fuel combustion creates large amounts of sulfur dioxide

EPA began regulating diesel fuel sulfur levels in 1933

Fossil Fuel Combustion Leads to Pollution

The chemistry of fuels comes from the source plant matter:

Carbon

Hydrogen

Nitrogen

Oxygen

Sulfur

These were major biogeochemical cycles (unit 1)

These chemicals, when burned, create primary pollutants

Anything that has negative effects on human health or the environment is considered a pol

Effects of Fossil Fuel Pollution

Pollutants cause harm to human life or the environment

Air pollutants are likely to come in contact with eyes, nose, and throat, causing irritation

Inhaled pollutants exacerbate existing lung conditions and can cause permanent lung damage

Air pollutants can damage plant tissue during photosynthesis and respiration

Unit 7.2: Photochemical Smog

The combustion of fossil fuels can produce primary pollutants such as nitrogen oxide

Volatile Organic Hydrocarbons

Named “volatile” because they can vaporize at room temperature

Increased presence in the atmosphere

Example:

Anthropogenic

Formaldehyde

Gasoline

Natural

Trees

Many plant oils

Formation of Photochemical Smog

Sources

Urban areas with many cars

Primary Pollutants

Nitrogen oxides

VOCs

Tropospheric Conditions

Sunlight

Heat

Secondary Pollutants

Ozone

PANs

Peroxyacyl nitrates

Factors Influencing Photochemical Smog

Timing:

Nitrogen oxide is produced early in the day

Morning rush hour

Ozone concentrations peak in the afternoon

Increase sun intensity and temperatures

Location and Seasonality:

Ozone levels are higher in sunny warm climates

Ozone levels are higher in the summer

The secondary pollutants that make up what we refer to as photochemical smog

Ozone

PANs

Aldehydes (a category of VOCs)

HNO3 (nitric acid)

Human Health Effects of Photochemical Smog

Photochemical Smog

Irritates the eyes, nose, and throat

Can worsen existing heart and lung conditions

Regular long-term exposure can cause lung cancer

Tropospheric Ozone

Effects in humans

Can worsen bronchitis and emphysema

Can trigger asthma

Causes permanent dam age to lung tissue

Additional environmental impacts of tropospheric ozone

Enters plants through the stomata and burns plant tissue, leading to leaf damage and reduce survival

Reducing Photochemical Smog

Reduce Nitrogen Oxides:

Catalytic Converters

Convert NO into O2 and N2

CO and hydrocarbons react to produce CO2 and H2O

Enforce emissions testing and standards for vehicles

Reduce VOCs:

Pump gas at night

Follow gasoline refueling instructions for efficient vapor recovery, being careful not to spill fuel, and always tightening your gas cap securely

Unit 7.3: Thermal Inversion

Thermal Inversion - under normal conditions in the troposphere, as the altitude increase, the temperature decreases

A reversal in this tend occurs in a layer above Earth’s surface

The warmer layer on top of the cooler surface air is referred to as an inversion

It is the opposite of the expected conditions

Thermal inversion “traps” cooler, denser air

Air does not rise, and pollutants do not disperse

Photochemical smog

Particulate matter

Factors that Influence Thermal Inversion

Geography can encourage inversion layers

Valleys

Nearby mountain ranges

Coastal or prevailing winds

These conditions make it more likely that cool air can be trapped beneath a warm layer

Pollution is intensified by the inversion

Large cities

High industrialization

Lots of vehicles

These facts make a location more prone to suffering health effects from an inversion

Unit 7.4: Atmospheric CO2 and Particulates

Anthropogenic VS Natural Pollution Sources

Air pollution is any substance in the atmosphere that has harmful effects on people, ecosystems, or infrastructure and the economy

Natural Sources of Carbon Dioxide

Regular sources of CO2 emissions

Respiration

Ocean outgassing (diffusion)

Decomposing biomass

Geological processes

Volcanoes

Ecosystem Disturbances

Wildfires

Is Carbon Dioxide a Pollutant?

Natural emissions are major contributor to atmospheric CO2 levels, but natural processes are also sinks for carbon dioxide

The net effect of natural CO2 sources and sinks is minimal

Natural sources are primarily “fast carbon” and not fossil carbon

Burning fossil fuels for power, transportation, and creating petroleum products adds excess carbon dioxide to the atmosphere

CO2 is a greenhouse gas and necessary to support life and maintain global temperatures

Excess CO2 that disrupts ecosystems, health, and the economy is a pollutant

Particulate Matter - is solid or liquid particles in the air that are small enough to be inhaled

Categorized based on particle size in microns (1 micron = 1 millimeter)

Particulate matter under 10 microns is inhalable

PM10 - between 2.5 and 10 microns in diameter

Between 0.0025 and 0.01 mm

Upper respiratory concern

PM2.5 - under 2.5 microns in diameter

Lower respiratory concern

Natural Sources of Particulate Matter

Pollen

Spores (plant, fungi)

Bacteria

Dust

Dust mites

Airborne soil

Sea salt

Geological Processes:

Volcanic dust

Sulfates

Ecosystem Disturbances:

Wildfires

Unit 7.5: Indoor Air Pollutants

Sources of Indoor Air Pollution

Indoor air pollution can come from natural sources, human-made sources, and combustion

Natural Sources

Mold

Dust

Radon

Human-made sources

Asbestos

Combustion (smoke)

Mold - can infect respiratory passageways

Water leaks and too much humidity can create perfect conditions for mold to grow

Can be found in homes and schools

Dust - contain particulates of different sizes

Smoke - produces particulates that irritate and damage respiratory systems

Sources of smoke include;

Candles burning

Use of fireplaces

Use of cookstoves that burn wood, charcoal, and animal dung

Use of unvented space heaters or kerosene heaters

Cigarette smoke

Smoke from nearby wildfires

Radon - a gas resulting from decaying uranium

Some rock and soils contain uranium

As uranium decays into radon-222, the gas escapes into the atmosphere and can seek into homes and buildings buoy on these soils

Radon moves up through the soil and can then enter a home

It is a naturally occurring gas, you cannot see or smell

It can dissolve in groundwater

Exposure to radon can cause lung cancer

Decays into radioactive particles

These particles are inhaled and deposited into the lungs

Cells of lung tissue becomes irritated, damaging DNA

This the second leading cause of lung cancer in America

Building owners can test for radon to determine risk and reduce risk of exposure

Selling cracks and venting can easily reduce risk

Asbestos - was used in insulation can cause lung cancer

No longer used in schools and public buildings

Products used to build and furnish homes and offices contribute to indoor air pollution

Lead can be found in paints in older homes

VOCs can be found in furniture, paneling and carpets, cleaning supplies, fabric softener dryer sheets

Formaldehyde can be found in building materials like treated woods, carpets, glues, and resins

Insulation can contain asbestos in older homes and buildings

These tiny glass fibers can cause lung disease

Combustion releases air pollutants

Nitrogen oxide

Sulfur dioxide

Particulates

Tobacco smoke

Carbon monoxide

Produced when fuel is burned

Household items produce fumes that release carbon monoxide poisoning

Small engines, stoves, lanterns, grills and fireplaces, furnaces, and cars and trucks are examples of this

Reacts with hemoglobin in red blood cells to create a molecule that can no longer carry oxygen

Impairs that ability of red blood cells and cause dizziness, nausea, and suffocation

Unit 7.6: Reduction of Air Pollutants

Clean Air Act - regulates the emission of air pollutants that affect human health

Regulation at a national level by cooperating with states and tribes

Reduction of automobile emissions

Eliminating lead in gasoline

Encouraging cleaner technologies in transportation

Reduction of acid rain

Determine levels of how much pollution is permissible by industries

Promoting technologies for reductions in sulfur dioxide and nitrogen oxides

Phased out pollutants depleting Earth’s stratospheric ozone

Regulations for managing tropospheric, or ground level ozone

Sets air quality standards and encourages technologies to protect the health of humans and the environment

Alternative Fuels

Clean air act supports this because it reduces pollutants in emissions

Natural gas

Propane

Ethanol

Electricity

Biofuels

Conservation Actions to Reduce Emissions

Energy efficiency in appliances and buildings reduce fuel use and emissions

Water based rather than solvent based paints and cleaners reduce VOCs

Improved transportation planning for passengers and freight reduce fuel use and emissions

Higher fuel standards and cleaner running engines for cars, trucks, and planes reduce fuel use

Individual and community actions like composting, recycling, carpooling, no-idle zones, and other actions can have large impacts

Vapor recovery nozzles reduce fumes

The vapor recovery system captures the vapors and sends them to the underground storage tank

New technologies improve reductions, and more efficient nozzles have been designed

Catalytic converters reduce the toxicity of emissions

Nitrogen oxide pollution is reduced by a catalyst through a reduction reaction (removing oxygen). This breaks up nitrogen oxides into nitorgen and oxygen gases.

Another catalyst works by an opposite chemical reaction called oxidation (adding oxygen) and turns carbon monoxide into carbon dioxide.

Another oxidation reaction turns unburned hydrocarbons in the exhaust into carbon dioxide and water.

Scrubbers remove pollutants from exhaust streams

When coal is burned, there are pollutants that are released as gas and particulates

These gasses are released via the flue, or smokestacks, and enter the atmosphere where they cause air and water pollution

The Clean Air Act requires scrubber technologies to remove pollutants like sulfur oxides, nitrogen oxides, and particulates

Wet scrubbers use liquids to capture pollutants

Wet scrubbers use a spray, or mist, of liquid to capture or change pollutants

When particulates and dust are an issue, water alone can be the liquid

For sulfur oxides, the liquid is often a combination of limestone powder and water that makes a slurry

The sulfur oxides interact with the limestone (a buffer) and converts it into a synthetic form of gypsum

This gypsum can be used as drywall, not all industries utilize this product

Dry scrubbers use dry substances to capture pollutants

They use dry particles, or reagents, to capture or change pollutants

Due to added weight, the particles will then fall to the bottom of the chamber and be collected by a screen

Although highly effective, dry scrubbers don’t remove as many pollutants as wet scrubbers

Electrostatic Precipitators Use Electrical Charge to Reduce Pollutants

These devices force the gas through a chamber that adds a charge to the pollutants

As the soot particles move past metal plates or filters that have an opposite charge, the particles stick there

These devices can be used as the first step before the flue gases move into a scrubber chamber

Technologies are effective but create a waste product

Managing the waste ash and sludge can cause issues, these need to managed to prevent threats to the environment and human health

Unit 7.7: Acid Rain

The pH scales measures acidity and alkalinity of materials

There are both natural and human-made sources of acid rain

Vehicles burning fossil fuels emit nitrogen oxides (NOx)

Nitrogen oxide reacts with water resulting in nitrous acid with nitric acid

Coal-burning power plants release nitrogen oxides (NOx) and sulfur dioxides (SO2)

Sulfur dioxide reacts with water, resulting in sulfurous acid then sulfuric acid

Natural source emit some acid forming compounds

Volcanos, geysers, and hot springs can contribute sulfur dioxides, nitrogen oxides, and carbon dioxide to the atmosphere

However, most of these pollutants that cause acid rain are from the burning of fossil fuels

Formation of Acid Rain

Nitric acid and sulfuric acid can be in the form of dry deposits or rain/snow

The Acid Rain Pathway

Sulfur dioxide and nitrogen oxides from our burning of fossil fuels and some natural sources enter the atmosphere

SOx and NOx react with water in the atmosphere and are carried long distances by winds

These pollutants can travel long distances, as when they are released high into the atmosphere, this gives them more time to react with water, increasing the likelihood that acid rain will form

Acid deposition can greatly impact communities and environments downwind of coal-burning power plants

Acid rain and dry particles can then call to the Earth’s surface

Forests, soils, and aquatic systems, even human structures are impacted by acid deposition

Forests and Soils are Impacted Several Ways

Aluminum Toxicity

Acid rain promotes aluminum ions to leach from soils, which is toxic to plants and aquatic life

Calcium Deficiencies

Tree roots are unable to take up calcium when aluminum ions are present

Calcium is critical for normal cell processes, and without it trees and plants suffer

Reduced Photosynthesis

Damaged needles and leaves, as well as nutrient deficiencies caused by changing soil chemistry, means plants don’t photosynthesize as effectively

Aquatic life has a range of tolerance for acidic conditions

More acidic lakes and streams can result in death, skeletal deformities, and damaged eggs of fish and other aquatic life

Acid rain damages human-made structures

Metal and stone can be eroded by acid deposition

Many statues are made of marble a rock that contains calcite, which is dissolved by acid deposition

Not all regions respond the same way

The bedrock and soils determine how vulnerable an area is to acid rain

Soils rich in magnesium, calcium carbonate, and limestone can buffer, or neutralize, the acid

Lakes surrounded by granite that have thin, nutrient poor soils, are vulnerable

Forests and lakes or New England, and high elevations, have those conditions

Unit 7.8: Noise Pollution

Noise can cause damage to human health

Noise Pollution - any noise that causes stress or has the potential to damage human health

Noise is measured in decibels on a logarithmic scale

Human hearing can be damaged with sudden or prolonged exposure above 85 decibels

Sources of Noise Pollution

Transportation

Loud noise levels are associated with railroads, mass transit, airports, sirens, heavy traffic, and even motorcycles

Machinery associated wit industry

Construction activities

Trucks jackhammers, nail guns, and other activities

Hearing loss is one consequence of noise pollution

Other consequences include

Stress

Depression

Anxiety

High blood pressure

Heart disease

US Noise Control of 1972 - enables the Environmental Protection Agency to regulate noise. EPA sets emission standards for courses of noise from transportation, machinery, and construction

The Occupational Safety and Health Association (OSHA) sets limits on noise exposure in the workplace

The Quiet Communities Act provides funding to help communities reduce noise associated with airports

Noise pollution can cause stress

Anthropogenic noise can cause stress, resulting in

Reduced reproduction

Decline in overall health

Disrupted communication

Noise can mask sounds for both predator and prey

By masking sounds, noise pollution can make it difficult for

Predators to find prey

Prey to elude predators

Noise pollution can altar migration routes

Birds, whales, and game animals like these mule deer are impacted by noise from machinery and transportation

During migration, animals avoid areas that previously provided critical food, nesting, or resting