Environmental Science Chapter 6 Notes #1

Air Pollution Definition: Harmful substances in the air at unhealthy levels Substances can be Solids, Liquids, or gases Mostly the result of human activities Natural sources as well Volcanoes, dust, spores, pollen

Air Pollution In some areas there are “air pollution” days like we get “snow” days Example – Mexico City Birds sometimes drop dead out of the trees from too much air pollution People and up with serious health problems

Air Pollution Primary Pollutant Put directly into the air by human activity Ex. Soot from smoke, CO, Sulfur and Nitrogen Oxides, VOCs, and particulate matter See Page 152 and 153 Sources Transportation, Fuel Burning, Industrial, Construction/agriculture

Air Pollution Secondary Pollutant When primary pollutants come into contact with other chemicals, and a reaction takes place. EX. Smog Term combining words “smoke” and “fog” Ozone

Air Pollution Over 1/3 of pollution comes from motor vehicles Clean Air Act – gives the EPA the right to control automobile emissions Eliminated lead from gas (reduced lead pollution by 78% in only 7 years) Catalytic converters (clean gases before they exit the vehicle) Car pooling also helps Ethanol = corn/sugar based fuel for cars Less polluting because the by-products are CO2 and H2O

Air Pollution Thermal Inversions General Fact- Warm air rises In a thermal inversion – a layer of warm air traps cool air at the Earth – also trapping pollutants Normally pollutants would rise up with the cooling air

Air Pollution Acid Rain Highly acidic precipitation A pH less than 5.6 pH scale -0 to 14, what does this mean? Pop is about a 3.5 to 4.0 Mostly Caused by nitrogen and sulfur oxides They form sulfuric and nitric acid in the air Can cause leeching (of Al) and acid shock (when snow melts) Both kill living things Some areas spray powdered lime to counteract the effects of acid rain. Why would this work?