Unit 7 · Atmospheric Pollution

Air pollutants from coal combustion ● (core concept) — Coal combustion releases air pollutants including carbon dioxide, sulfur dioxide, toxic metals, and particulates.

Air pollutants from fossil fuel combustion ● (core concept) — The combustion of fossil fuels releases nitrogen oxides into the atmosphere. They lead to the production of ozone, formation of photochemical smog, and convert to nitric acid in the atmosphere, causing acid rain. Other pollutants from fossil fuel combustion include carbon monoxide, hydrocarbons, and particulate matter.

Sulfur dioxide from fossil fuels ● (core concept) — Air quality can be affected through the release of sulfur dioxide during the burning of fossil fuels, mainly diesel fuels.

Clean Air Act ● (core concept) — The Clean Air Act regulates the emission of air pollutants that affect human health. Through the Clean Air Act, the Environmental Protection Agency (EPA) regulated the use of lead, particularly in fuels, which dramatically decreased the amount of lead in the atmosphere.

Primary vs. secondary pollutants ● (core concept) — Air pollutants can be primary pollutants, emitted directly from a source, or secondary pollutants, which form in the atmosphere through chemical reactions.

Photochemical smog formation ● (core concept) — Photochemical smog is formed when nitrogen oxides and volatile organic hydrocarbons react with heat and sunlight to produce a variety of pollutants.

Environmental factors in smog formation ● (core concept) — Many environmental factors (e.g., sunlight, temperature, wind, topography) affect the formation of photochemical smog.

Daily and seasonal smog patterns ● (core concept) — Nitrogen oxide is produced early in the day. Ozone concentrations peak in the afternoon and are higher in the summer because ozone is produced by chemical reactions between oxygen and sunlight.

Volatile Organic Compounds (VOCs) ● (core concept) — Volatile Organic Compounds (VOCs), such as formaldehyde and gasoline, evaporate or sublimate at room temperature. Trees are a natural source of VOCs.

Urban photochemical smog ● (core concept) — Photochemical smog often forms in urban areas because of the large number of motor vehicles there.

Reducing photochemical smog ● (core concept) — Photochemical smog can be reduced through the reduction of nitrogen oxide and VOCs.

Health effects of photochemical smog ● (core concept) — Photochemical smog can harm human health in several ways, including causing respiratory problems and eye irritation.

Thermal inversion ● (core concept) — During a thermal inversion, the normal temperature gradient in the atmosphere is altered as the air temperature at the Earth's surface is cooler than the air at higher altitudes.

Inversion and trapped pollution ● (core concept) — Thermal inversion traps pollution close to the ground, especially smog and particulates.

Natural sources of CO2 ● (core concept) — CO2 appears naturally in the atmosphere from sources such as respiration, decomposition, and volcanic eruptions.

Natural sources of particulate matter ● (core concept) — There are a variety of natural sources of particulate matter, such as volcanic eruptions, dust storms, and wildfires.

Carbon monoxide (indoor) ● (core concept) — Carbon monoxide is an indoor air pollutant that is classified as an asphyxiant.

Indoor particulates ● (core concept) — Indoor air pollutants that are classified as particulates include asbestos, dust, and smoke.

Sources of indoor air pollutants ● (core concept) — Indoor air pollutants can come from natural sources, human-made sources, and combustion.

Natural indoor air pollutants ● (core concept) — Common natural source indoor air pollutants include radon, mold, and dust.

Human-made indoor air pollutants ● (core concept) — Common human-made indoor air pollutants include insulation; VOCs from furniture, paneling, and carpets; formaldehyde from building materials, furniture, upholstery, and carpeting; and lead from paints.

Combustion indoor air pollutants ● (core concept) — Common combustion air pollutants include carbon monoxide, nitrogen oxides, sulfur dioxide, particulates, and tobacco smoke.

Radon-222 ● (core concept) — Radon-222 is a naturally occurring radioactive gas that is produced by the decay of uranium found in some rocks and soils.

Radon infiltration of homes ● (core concept) — Radon gas can infiltrate homes as it moves up through the soil and enters homes via the basement or cracks in the walls or foundation. It is also dissolved in groundwater that enters homes through a well.

Radon-induced lung cancer ● (core concept) — Exposure to radon gas can lead to radon-induced lung cancer, which is the second leading cause of lung cancer in America.

Methods to reduce air pollutants ● (core concept) — Methods to reduce air pollutants include regulatory practices, conservation practices, and alternative fuels.

Vapor recovery nozzle ● (core concept) — A vapor recovery nozzle is an air pollution control device on a gasoline pump that prevents fumes from escaping into the atmosphere when fueling a motor vehicle.

Catalytic converter ● (core concept) — A catalytic converter is an air pollution control device for internal combustion engines that converts pollutants (CO, NOx, and hydrocarbons) in exhaust into less harmful molecules (CO2, N2, O2, and H2O).

Scrubbers ● (core concept) — Wet and dry scrubbers are air pollution control devices that remove particulates and/or gases from industrial exhaust streams.

Coal plant pollution controls ● (core concept) — Methods to reduce air pollution from coal-burning power plants include scrubbers and electrostatic precipitators.

Acid deposition ● (core concept) — Acid rain and deposition is due to nitrogen oxides and sulfur oxides from anthropogenic and natural sources in the atmosphere.

Sources of acid deposition ● (core concept) — Nitric oxides that cause acid deposition come from motor vehicles and coal-burning power plants. Sulfur dioxides that cause acid deposition come from coal-burning power plants.

Downwind effects of acid deposition ● (core concept) — Acid deposition mainly affects communities that are downwind from coal-burning power plants.

Effects of acid deposition ● (core concept) — Acid rain and deposition can lead to the acidification of soils and bodies of water and corrosion of human-made structures.

Limestone buffering of acid rain ● (core concept) — Regional differences in soils and bedrock affect the impact that acid deposition has on a region — for example, limestone bedrock's ability to neutralize the effect of acid rain on lakes and ponds.

Noise pollution ● (core concept) — Noise pollution is sound at levels high enough to cause physiological stress and hearing loss.

Sources of noise pollution ● (core concept) — Sources of noise pollution in urban areas include transportation, construction, and domestic and industrial activity.

Noise pollution effects on animals ● (core concept) — Some effects of noise pollution on animals in ecological systems include stress, the masking of sounds used to communicate or hunt, damaged hearing, and causing changes to migratory routes.