Air and Air Pollution

Nitrogen

Approximately 78% of the Earth’s atmosphere

Oxygen

About 21%

Argon

Roughly 0.93%

Carbon Dioxide

Around 0.04%

Air pollutants

substances in the atmosphere that can have harmful effects on human health

Primary air pollutants

emitted, unchanged, directly into the atmosphere

Carbon Monoxide

Emitted from vehicle exhaust and incomplete combustion of fossil fuels.

Sulfur Dioxide

Released from burning fossil fuels, especially coal, and from industrial processes

Nitrogen Oxides

Produced from vehicle engines and industrial processes.

Volatile Organic Compounds

Emitted from vehicle exhaust, industrial processes, and chemical solvents

Particulate Matter

Tiny particles or droplets in the air, such as dust, dirt, soot, or smoke

Ozone

Formed when nitrogen oxides and volatile organic compounds react in the presence of sunlight

Smog

A mixture of air pollutants that forms over urban areas

Acid Rain

Results from sulfur dioxide and nitrogen oxides reacting with water vapor

Volcanic Eruption

Emit sulfur dioxide, particulate matter, and other gases directly into the atmosphere

Wildfires

Release large amounts of carbon monoxide, nitrogen oxides, particulate matter, and volatile organic compounds

Dust Storms

Carry dust particles across large distances, especially in arid and semi-arid regions

Biogenic Emissions

include natural emissions from plants (VOC) and decaying organic matter