Chapter 17: Atmospheric Science and Air Pollution

Atmosphere surrounds earth consists of N2, O2, Ar and others today's altering molecules consist of CH4, O3, CO2 made up of layers ozone layer

Other Atmospheric Properties atmospheric pressure force per unit of area that air exerts on the surface of Earth declines with altitude atmospheric humidity ratio of water vapor contained in a given volume of air in relation to it's maximum amount possible the more humidity the hotter it seems

Seasons determined by the positioning in relation to the sun atmosphere absorbs 70% of the energy the shorter the distance, the more intense the sun rays solar radiation intensity is lower at the poles and higher at the equator tilting of the planet causes the seasons to occur

Air Circulation known as convective circulation caused by differences in humidity and temperature warm air rises as it is less dense cold air descends becoming denser

Weather & Climate Weather specifies atmospheric conditions over short periods of time and related to relatively small areas Climate describes patterns of atmospheric conditions across large regions and over long periods of time

Weather depends on the fronts affected by the pressure systems cold→ thunderstorms warm→ light rain affected by the pressure systems high→ fair to dry weather low→ results in clouds and precipitation

Thermal Inversion cooler air appears under warmer air prevents normal convective circulation to occur pollution is trapped under the inversion layer creating health problems like asthma killer smog in London asthma in San Joaquin valley

Global Climate Patterns Hadley cells: between equator and 30º heavy rain at the equator arid at 30º

Global Climate Patterns Ferrer cells and polar cells lift air creating rain at ~60º

Wind Patterns caused by the interaction of Hadley and Ferrer cells and Earth's rotation Coriolis effect: winds are curved

Outdoor Air Pollution air pollutants natural sources human made sources

Natural Pollutants we have no control, occur naturally volcano eruptions Mt. Pinatubo produces particles circle the globe and remain in suspension for months acid rain affect temperature

Natural Pollutants dust storms Dallas dust storm 2007 Texas dust storm 1930's

Natural Pollutants Fires soot and gases fuel buildup slash-and-burn in tropics El Niño 2000 TX LA T Gulf Coast

Human Created Outdoor Pollution primary pollutants emitted directly to the troposphere can be harmful to the environment can form chemicals harmful to the environment secondary pollutants react with constituents of the atmosphere

Clean Air Act 1970 1990 set stricter standards for air quality imposed limits to emissions funds for pollution control research 1990 strengthen air quality standards emission trading program for sulphur dioxide other emission trading programs developed

EPA Standards carbon monoxide (CO) sulphur dioxide (SO2) nitrogen dioxide (NO2) tropospheric ozone (O3) particulate matter lead (Pb)

Carbon Monoxide colorless odorless incomplete combustion in the U.S. 78% of it comes from vehicles small concentrations can be lethal to most living organisms

Sulphur Dioxide colorless pungent odor power plants of coal once in the atmosphere SO2 reacts forming SO3 and later forming H2SO4 H2SO4 forms acid rain

Nitrogen Oxides contributes to smog NO2 is foul smelling, redish brown gas NOx cause acid rain product of combustion engines vehicles produce 50% of the U.S. NOX electricity production and industry the rest

Ozone product of sunlight + heat + NOX + carbon chemicals health risk because of its instability→ O2 + Oxygen ion oxygen ion can cause tissue damage tissue damage can cause respiratory problems

Particulate Matter particles suspended in air primary pollutants → dust and soot secondary pollutants → sulphates and nitrates can damage respiratory tissues wind-blown result of human activities

Lead particulate matter enters food chain can cause nervous system malfunction present in gasoline to improve performance industrialized nations phased out leaded gasoline industrial metal smelting is the problem now

VOCs volatile organic compounds hydrocarbons methane forms part of natural gas propane used as portable fuel butane used in portable lighters octane component of gasoline

Pollutants in the U.S. 2006 137 trillion tons EPA data

Pollution Decreased since 1970 emissions declined 53% since 1970 cleaner burning vehicles catalytic converter clean coal technology baghouse filters electrostatic precipitators scrubbers phase-out of lead in gasoline

Toxic Pollutants 188 toxic pollutants identified by the Clean Air Act in 1990 effects on people cancer reproductive defects neurological problems developmental problems affect the immune system respiratory diseases

Policy: Bush Administration elimination of new source review of 1977 new pollution targets retrofitting aging plants with new technologies industry protested: too costly Bush Administration exempted older plants allowed installing only "the best available" technology IF they ever upgraded the plant Clear Skies (stopped by the Senate in 2005) from command-and-control to a market-based cap-and-trade

Smog fogs polluted by smoke= smog industrial smog photochemical smog

Industrial smog gray-air smog coal or oil burning CO, CO2, soot London 1952 gray-air smog coal or oil burning CO, CO2, soot mercury and sulfur in the carbon sample sulfur reacts forming SO2 sulphuric acid ammonium sulphate Problems today: China, India, Eastern Europe

Photochemical smog requires light brown-air smog ozone NOx VOCs irritates eyes, nose, throat car inspections reduction of vehicles driven per day allow certain cars to drive certain days of the week promote mass transit Houston 2000

Problems at Rural Areas airborne pesticides industrial pollutants from cities, factories and power plants migrate methane from cattle (18%) feedlots CH4, dust, NH4, SOx can cause respiratory problems

Industrialization is worsen air quality China Industrialization is worsen air quality caused by factories and power plants emissions are released with little effort to control pollution China & India have 58% of premature deaths worldwide (WHO) Asian brown cloud reduces sunlight decreases productivity

Synthetic Chemicals CFCs (chlorofluorocarbons) affects the ozone layer creating the ozone hole in Antarctica increases UV radiation leads to more skin cancer ecological effects still unknown hole in the arctic Arctic hole

Montreal Protocol of 1987 addressed ozone depletion 180 nations agreed to cut CFCs production in half production and use has dropped by 95% alternative chemicals CFCs take very long to brake down www.epa.gov/cppd

Acid Deposition originates with the NOx and SOx forms of precipitation known as acid rain rain, snow, sleet and hail fog dry particles originates with the NOx and SOx pollutants react with water, O2, oxidants produce compounds of low pH (acids) these are suspended in the troposphere before falling as rain can cause political bickering

Acid Rain alters soil composition leaches chemicals from the soil harming plants and soil organisms also mobilizes toxic chemicals converts them to soluble forms affects agriculture affect lakes and rivers causing high mortality in fishes and amphibians

Acid Rain erosion of buildings corrodes cars erosion of statues and obelisks has not been reduced as expected in 1990 more reduction of sulphur oxides and nitrogen oxides need to occur

Indoor Air Pollution higher concentration of pollutants indoor than outdoor workplaces, schools, homes volatile chemicals in the air insecticides cleaning fluids plastics chemically treated wood

Other Sources wood burning chimneys cooking tobacco smoking radon

Indoor VOC Pollution perfumes paints plastics oils/candles cleaning fluids adhesives (glues) pesticides and insecticides ink (fax, photocopiers, printers) color films

Living Organisms also Pollute dust mites animal dander mold bacteria THE END