APES Unit 7

Air pollution

Presence of substances in the atmosphere other than N2, O2, CO2, and H2O

Criteria air pollutants

Common regulated air pollutants such as SO2, NOx, CO, PM, Pb, and ozone

Natural emissions

Air pollution from volcanoes, lightning, forest fires, and plants

Anthropogenic emissions

Air pollution produced by human activities

Incomplete combustion

Combustion that produces CO due to insufficient oxygen

Complete combustion

Combustion that produces CO2 when oxygen is sufficient

Sulfur dioxide (SO2)

Acidic, corrosive gas from coal and oil combustion and volcanoes

Effects of sulfur dioxide

Respiratory irritation and formation of acid rain

Nitrogen oxides (NOx)

Irritant gases from vehicles and fossil fuel combustion

Effects of nitrogen oxides

Respiratory irritation, acid rain, and over-fertilization

Carbon monoxide (CO)

Colorless gas from incomplete combustion that prevents oxygen transport in blood

Carbon monoxide poisoning

Condition caused by CO binding to hemoglobin

Carbon dioxide (CO2)

Gas from fossil fuel combustion that contributes to global warming

Particulate matter (PM)

Solid or liquid particles suspended in air

Effects of particulate matter

Haze formation and respiratory health impacts

Lead (Pb)

Toxic metal once added to gasoline

Effects of lead exposure

Impaired nervous system, learning, and concentration

Volatile organic compounds (VOC)

Organic compounds that evaporate easily at atmospheric temperatures

Sources of VOCs

Fuels, solvents, paints, and incomplete combustion

Effects of VOCs

Respiratory irritation and smog formation

Primary pollutants

Pollutants emitted directly, such as CO, NOx, and SO2

Secondary pollutants

Pollutants formed in the atmosphere, such as ozone and acids

Ozone (O3)

Secondary pollutant formed from NO2 and sunlight

Stratospheric ozone

Protects Earth by blocking UV-C and part of UV-B

Tropospheric ozone

Harmful pollutant that damages lungs and plants

Chlorofluorocarbons (CFCs)

Synthetic compounds used in refrigeration

Polychlorinated biphenyls (PCBs)

Toxic compounds associated with cigarette smoke

Clean Air Act (CAA)

U.S. law regulating air pollutants harmful to health and welfare

Cap-and-trade system

Limits emissions by allowing trading of pollution permits

Major source of CO and NOx

On-road vehicles

Major source of SO2

Coal-fired electricity generation

Major source of PM

Road dust

Photochemical smog

Air pollution formed from NOx, VOCs, and sunlight

Photochemical oxidants

Reactive compounds formed during photochemical smog

Los Angeles smog

Photochemical smog common in sunny urban areas

Haze

Reduced visibility caused by particulate matter

Sulfurous smog

Industrial smog associated with SO2, historically in London

Thermal inversion

Atmospheric condition that traps pollutants near the ground

Radiation inversion

Cool air trapped beneath warm air at night

Advection inversion

Warm ocean air moving over cooler land

Topographic inversion

Pollutant trapping in valleys or basins

Indoor air pollution

Air pollution inside buildings

Indoor air pollution deaths

Approximately 4 million deaths annually worldwide

Indoor particulate matter

PM from fireplaces and wood stoves

Indoor VOCs

Pollutants from cleaners, paints, and furniture

Carcinogenic indoor pollutants

Cancer-causing compounds such as tobacco smoke

Radon

Carcinogenic radioactive gas found in basements

Asbestos

Carcinogenic fibers found in some building materials

Reducing indoor air pollution

Material substitution, ventilation, and contaminant absorption

Acid rain

Deposition of acidic precipitation formed from NO2 and SO2

Nitric acid formation

NO2 reacting with water to form HNO3

Sulfuric acid formation

SO2 reacting with water to form H2SO4

Effects of acid deposition

Lower pH, metal mobilization, ecosystem damage

Noise pollution

Unwanted sound from transportation and industry

Effects of noise pollution

Mental health issues and wildlife disruption

Air pollution reduction strategies

Cleaner fuels, efficiency, and post-combustion controls

Fluidized bed combustion

Coal burning method that reduces PM and SO2

Scrubbers

Devices that spray water to remove pollutants

Baghouse filters

Fabric filters that remove particulate matter

Electrostatic precipitators

Use electrical charge to remove PM

Catalytic converters

Reduce CO, NOx, and VOC emissions from vehicles