Air Pollution Overview and Types

Study Notes

Air pollution is a gas, liquid, or solid dispersed in the air in large enough quantities to harm human or animal health, kill/hinder plant growth, or damage the environment.
It can also cause nuisances such as reduced visibility or unpleasant odors.
Air pollution is defined as any harmful contaminant introduced into the air.
Pollution can be carried great distances by air and wind.
Industrial pollutants can be found far from the source.
Pollutants often concentrate at the poles.

Primary Pollutants: Released directly from a source. Examples: dust, smoke, nitrogen, carbon.
Secondary Pollutants: Formed when primary pollutants react or combine.

Carbon Monoxide (CO):
- Produced by incomplete burning of organic materials.
- Automobiles are the largest source.
- Not persistent.
- Binds to hemoglobin, reducing its ability to carry oxygen.
- Most dangerous in enclosed spaces.
- Cigarette smoking is a source.
Volatile Organic Compounds (VOCs):
- Group of organic compounds containing carbon and hydrogen.
- Evaporated from automobile fuels, incompletely burned fuels.
- Catalytic converters reduce VOCs in exhaust.
Particulates:
- Minute solid particles (<10 microns) dispersed into the atmosphere.
- Examples: smoke, asbestos, dust, ash.
- Can accumulate in lungs, hindering gas exchange.
Sulfur Dioxide (SO2):
- A sulfur and oxygen compound, formed during the burning of sulfur-containing fossil fuels.
- Burning coal is a major source.
- Volcanoes and hot springs are natural sources.
- 200 tons per day from modern steam plants.
Nitrogen Oxides (NOx):
- Formed during combustion.
- Automobile exhaust is a major source.
- Precursors to acid rain and photochemical smog.
- Greenhouse gas.
Lead (Pb):
- Enters the air as a particle or part of dust.
- Previously emitted mainly from leaded gasoline.
- Now primarily from industrial processes and burning fossil fuels.

Anthropogenic (Man-Made) Sources:
- Controlled burning in agriculture and forestry (prescribed burning).
- Wildfires.
- Mobile sources (motor vehicles, marine vessels, aircraft).
Natural Sources:
- Dust storms.
- Dust in areas with little vegetation.
- Methane emitted by animals (e.g., cattle).
- Radon gas from radioactive decay.
- Smoke and CO from wildfires.
- VOCs from vegetation in some regions.
- Volcanic activity (sulfur, chlorine, ash).