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– 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

Texas dust storm 1930's Dallas dust storm 2007

Natural Pollutants

Fires– soot and gases– fuel buildup– slash-and-burn

in tropics– El Niño

2000

Gulf Coast

T TX LA

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– 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 mercury and sulfur in the carbon sample sulfur reacts forming SO2

– sulphuric acid– ammonium sulphate

Problems today: China, India, Eastern Europe

London 1952

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 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

China

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

– 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