air pollution (nres 102)

8/10/2019 Air Pollution (NRES 102)

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Air Pollution


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What are air pollutants?

gases and aerosols we add toatmosphere

best known is smog industrial - smoke and fog

photochemical - emissions + sunlight

US has worked to control most airpollutants for many years


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Why do we care?

visual quality of the environment

vegetation, animals, soil

water quality natural and artificial structures

human health


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Major Air Pollutants

sulfur oxides (SOx)

nitrogen oxides (NOx)

carbon monoxide (CO) ozone and other photochemical oxidants

volatile organic compounds (VOCs)

suspended particulate matter lead (Pb)

air toxics


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Many adverse effects from

these pollutants

chronic

acute

carcinogenic


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Atmospheric inversions


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Great London Smog of 1952

1000s died, much of country

affected


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Primary and Secondary Pollutants

primary pollutants those emitted directly into the air

hydrocarbons, particulates, SOx, NOx

secondary pollutants produced through reactions between

primary pollutants and normal atmosphericcompounds

ozone


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What are sources?

combustion of fossil fuels (coal, gasoline,diesel)

always incomplete combustion stationary versus mobile sources

what comes out stack are primary pollutants

direct products of combustion

USEPA measures ambient concentrations 1970 Clean Air Act - taller stacks to meet ground

level standards


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Sudbury, Ontario

1250 feet tall


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US Emissions for 2011


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Trends in Growth vs. Emissions


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USemissions


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Ozone (O3)

good versus bad ozone ground versus stratosphere

ground level major pollutant billions of dollars in crop losses eachyear

respiratory hazard for human healtheffect

not easy to reduce


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Ozone (O3)

secondary pollutant photochemical oxidant

source is VOCs, NO2, and sunlight most cities dont meet ozone

standards

difficult (expensive) to reduce caremissions further


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Ozone Monitoring


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Ozone in the Midwest


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Ozone Impact on Crop Yields


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Acid rain (acidic deposition)

SOxH2SO4(sulfuric acid)

NOxHNO3(nitric acid)

long-range transport

pH < 5.6

both precipitation and dry deposition


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Major Sources of SO2Emitters


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pH scale


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Acid rain effects


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Bondville, IL

Acadia National Park, Maine


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Acid rain effects on aquatic

organisms


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Acid rain today

still affecting forests

and surface waters more of a nitrogen

than sulfur problem

certainly 1990 CleanAir Act helped


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Air Pollution: Legislation andStandards

Clean Air Act of 1970 amendments in 1977 and 1990

Amendments of 1990 comprehensive regulations enacted by U.S

congress that address acid rain, toxicemissions, ozone depletion and automobileexhaust

in 1990 more flexibility, market system allowspolluters to choose most cost effectivemethods

still cant meet ozone standards


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SO2scrubber

F h f


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SoyFace at the University ofIllinois


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Air pollution today

we have made major improvements lead, SOx, other gases

ozone still biggest problem billions in crop losses

cars large sources, although each car

is now much cleaner

air pollution (nres 102)

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