Transcript Air Pollution

Air Pollution
What’s in the Air?
• Nitrogen, oxygen, carbon dioxide, water
vapor, and other gases
• Air pollution
– Solid particles and gases that are released
into the air are called emissions.
– Motor vehicles release gases such as carbon
monoxide
Smog
• Photochemical Smog
– Thick brownish haze formed when certain
gases in the air react with sunlight.
• Sources
– Gases emitted by automobiles and trucks and
industrial facilities
• Produce ozone
Smog
• Temperature Inversion
– Normally, pollutants rise high in the air and
blow away.
– During a temperature inversion, a layer of
warm air traps pollutants close to the ground
Smog
• Health Effects
– Itchy, watery eyes and a scratchy throat
– Lung problems
– Harm the body’s defenses against infection
– Smog alert
Acid Rain
• Rain is naturally a little acidic
• When precipitation is mixed with nitrogen
oxides and sulfur oxides produced by the
burning of coal and oil, the process
produces nitric acid and sulfuric acid
– Acid rain changes the conditions in ponds and
lakes, affecting the wildlife.
– Acid rain on the ground can damage plants.
The Ozone Layer
• Even a small amount of ozone in the
atmosphere protects people from the
effects of too much ultraviolet radiation.
• Ozone Hole
– Chlorofluorocarbons or “CFCs” block the
cycle that absorbs radiation.
• Refrigerators, air conditioners, aerosol spray cans
• 1990 many nations signed an agreement to ban
the use of almost all CFCs by the year 2000.