Unit 3 “Atmospheric Science & Air Pollution”

Atmosphere Atmosphere – thin layer of gases that surround the earth; composed of 5 sub layers – 1. Troposphere – closest to the earth, has most oxygen of any of 5 – 2. Stratosphere – Ozone predominantly found here – 3. Mesosphere – Ionosphere (weakly charged ions) located in upper portion – 4. Thermosphere – increase in temperature; uppermost portion of Ionosphere located here – 5. Exosphere – interface between earth’s atmosphere and space; very few gases

Atmosphere

Atmospheric Properties Composition of gases: 78% N, 21% O, 1% trace gases As altitude increases, pressure ___________. Why? As altitude increases (exception in thermosphere), temperature ____________. Why? As altitude increases, density ___________. Why? videos/weather-101-sci videos/weather-101-sci

Ozone Layer Found in the Stratosphere and is composed of O 3 molecules Blocks UVA and UVB rays from reaching earth’s surface In the latter part of the 20 th century, due to the use of products containing CFC’s, the Ozone Layer was depleted In the 1990’s many governments banned the use of CFC’s; as a result, the hole in the Ozone was reduced

Ozone Layer Depletion Keeping Ozone Layer intact is important because it keeps harmful UV rays from reaching the earth’s surface thereby preventing skin cancer

Weather and Climate Weather – day to day fluctuations in temperature and precipitation Climate – average weather conditions from year to year Whatever the conditions are in the atmosphere, those conditions will affect weather, and lastly climate

Air Masses and Pressure Systems Cold air mass = high pressure system Warm air mass = low pressure system As is the case with ocean currents, there are horizontal and vertical air currents Vertical air currents are called Convection Currents (hot air or fluid expands and is therefore less dense than its cooler surroundings, thus it rises; as it cools it contracts, becomes more dense and sinks down creating something of a rolling motion)

Air Masses and Pressure Systems Also, the ocean’s physical conditions (temperature etc.) affect the physical conditions of the atmosphere and vice/versa Evidence of how the ocean’s physical conditions affect atmosphere/weather is the occurrence of hurricanes (require warm ocean water to develop) the-Go/Sci-Media/Video/Water-and-weather the-Go/Sci-Media/Video/Water-and-weather

Air Pollutants Primary Pollutants – emitted into the troposphere already in a form that is harmful to life in the biosphere – ExampleCFC’s Secondary Pollutants – result of primary pollutants reacting with each other or other substances in the atmosphere to form new pollutants – ExampleAcid Rain

Air Pollutants Acid Rain – sulfur dioxide from coal burning power plants combines with water vapor Smog – coal and/or oil soot is released into the air Particulate pollution – small solid particles released into the air as a result of industrial processes; results in asthma and other respiratory ailments

Mitigating Air Pollutants Just as the Clean Water Act was put in place to protect the hydrosphere, the Clean Air Act was put into effect beginning in the 1960’s to protect the atmosphere The Clean Air Act of intent was to strengthen standards instituted in the 1970 version of the act; it also introduced an emissions trading program for sulfur dioxide (acid rain)

Market Based Incentives versus Government Regulations Incentives = voluntary; if done properly provide an economic incentive to industry to “clean up their act” Regulations = involuntary; government requires industry to comply with regulations, sometimes causing them to become less competitive Which is better? It depends on the variables involved!