- Air pollution
- Hydroxyl radical
- Smog
- Inversions


[SLIDE 1]

Air pollutants are substances in the atmosphere that have harmful effects. These include certain gases and aerosols such as dust, carbon, pollen, sea salts and microorganisms. Our atmosphere contains gases and water vapor that are essential to sustaining life.

3 factors affect amount of air pollution:
- amount of air pollutants entering the air
- amount of space into which they are dispersed
- mechanisms to remove pollution from the air

Pollutants that enter the troposphere are usually removed within hours and carried by cumulus clouds into the upper layers of troposphere. The atmosphere naturally cleans itself but some pollutants are resistant and linger. The worst of these are ozone-depleting pollutants such as chlorine and bromine compounds.


[SLIDE 2]

Hydroxyl Radical (OH) is a naturally occurring cleansing agent in the atmosphere that oxidizes many gaseous compounds into harmless products and can also bring these pollutants down to the ground or water by precipitation. 

Human activity has raised concentrations of pollutants in the air. Some pollutants such as carbon monoxide do not break down easily and take months to oxidize. Others like methane can even take years.


[SLIDE 3]

Air pollution began in volume during the Industrial Revolution in the 1800s with crowded cities and the use of coal for heating and energy.

Industrial smog is a combination of smoke and fog that lingers in the air and is irritating. It contains sulfur, soot and water vapor. You can find this type of smog around industrial plants.

Photochemical smog is a hazy fog produced by pollutants from automobile exhausts acted upon by sunlight. Nitrogen oxides and volatile organic carbon compounds (VOCs) produce this brownish, irritating smog.

Atmospheric brown clouds (ABC) are aerosols that create a blanket of pollution that deplete the ozone. These are new forms of smog common in south and central Asia and contain soot and carbon from biomass burning. Atmospheric brown clouds make it hard to see in these areas as they block the sun, reduce snow and ice, lower crop yields, and reduce rainfall.


[SLIDE 4]

Inversion is the condition of cooler air below and warmer air above. Inversions intensify with smog.

Inversions increase how long pollutants stay in the air. This can prompt health officials to tell people to stay indoors if they have breathing problems. Smog can cause headaches, nausea and eye and throat irritation.