Major Air PollutantsMajor Air PollutantsClean Air Act – EPAClean Air Act – EPA

Air PollutionDuring the 1950’s and 1960’s, most factories

looked like this

Air PollutionThe term “Smog” (smoke

and fog) was first used in 1905 to describe sulfur dioxide emission

In 1952, severe pollution took the lives of 5000 people in London

“It isn’t pollution that’s harming the environment. It’s the impurities in our air and water that are doing it.” Former U.S. Vice President Dan Quayle

Air PollutionNatural sources of air

pollution are often made worse by human activity.

Land use policies ‘Slash and burn’ agriculture Build up of fuel wood from fire

suppression in U.S. national forests

Air PollutionAnthropogenic (human

caused) air pollution1. Point sources

Coal-fired power plant’s smokestack

2. Non-Point sources Automobiles

Air PollutionPrimary air pollutants

Come directly out of a smokestack or exhaust pipe Carbon monoxide Carbon dioxide Sulfur dioxide Nitrous oxides Most suspended

particulate matterSecondary air pollutants

Have undergone chemical change or transformation in the presence of sunlight with water or with oxygen in the atmosphere Sulfuric acid Ozone

Major Sources of Primary PollutantsStationary SourcesCombustion of fuels for power and heat –

Power PlantsOther burning such as Wood & crop burning

or forest firesIndustrial/ commercial processesSolvents and aerosolsMobile SourcesHighway: cars, trucks, buses and

motorcyclesOff-highway: aircraft, boats, locomotives,

farm equipment, RVs, construction machinery, and lawn mowers

Human Impact on AtmosphereHuman Impact on AtmosphereRefining petroleum and burning fossil fuels

and manufacturingAdds CO2 and O3 to troposphereClimate ChangeProduces Acid RainReleases SO2 into troposphereReleases toxic heavy metals (Pb, Cd, and As)

into troposphere

Using Nitrogen fertilizers and burning fossil fuelsReleases NO, NO2, N2O, and NH3 into

troposphereProduces acid rain

Where are we at today?There are six criteria air pollutants established by the EPA

Carbon OxidesNitrogen OxidesParticulate matterLeadSulfur OxidesTropospheric

Ozone (ground)

Major Air PollutantsCarbon oxides Properties

colorless, odorless, heavier than air, 0.0036% of atmosphere

highly toxic gas that forms during the incomplete combustion of carbon-containing materials.

Sources incomplete combustion of fossil fuels

60 - 95% from auto exhaust Carbon monoxide (CO) is a 93% of

carbon dioxide (CO2) in the troposphere occurs as a result of the carbon cycle.

7% of CO2 in the troposphere occurs as a result of human activities (mostly burning fossil fuels).

Effects binds tighter to Hgb than O2 Impairs mental functions and visual

acuity, even at low levelsEPA Standard: 9 ppm

5.5 billion tons enter atmosphere/year

Mobile Source Mobile Source Emissions - COEmissions - CO

Major Air PollutantsSuspended particulate matter (SPM)Properties

Consists of a variety of solid particles and liquid droplets small and light enough to remain suspended in the air.

The most harmful forms of SPM are fine particles (PM-10, with an average diameter < 10 micrometers) and ultrafine particles (PM-2.5).

Sources Burning coal or diesel Volcanoes Asbestos PCBs, dioxins, pesticides unpaved roads, plowing, burning fields lint, pollen, spores

Effects lung damage, mutagenic, carcinogenic, teratogenic

EPA Standard: 50 ug/m3 (annual mean) SPM is responsible for about 60,000

premature deaths a year in the U.S.

Mobile Source Emissions: Fine Mobile Source Emissions: Fine Particulate Matter (PMParticulate Matter (PM2.52.5))

Major Air PollutantsNitrogen oxides•Properties• Reddish brown gas• NO reacts with air to form NO2.• NO2 reacts with water vapor in

the air to form nitric acid (HNO3) and nitrate salts (NO3

-) which are components of acid deposition.

•Sources• lightening and certain soil

bacteria.• fossil fuels combustion at high

temperatures• power plants, forest fires,

volcanoes, bacteria in soil•Effects• acid rain• lung and heart problems• decreased visibility (yellow

haze)• suppresses plant growth

•EPA Standard: 0.053 ppm

Mobile Source Emissions: Mobile Source Emissions: Nitrogen OxidesNitrogen Oxides

Major Air PollutantsLeadProperties

Heavy metalEffects

Is a powerful neurotoxin. accumulates in tissue affects kidneys, liver and nervous

system (children most susceptible) mental retardation possible carcinogen; 20% of inner city kids have high levels

Sources particulates, smelters, batteries Was removed from gasoline over three

decades ago Concentrations in the air have declined

precipitously Mercury from coal fired power plants

is now of greater concern than leadEPA Standard

1.5 ug/m3

2 million tons enter atmosphere/year

Major Air PollutantsVolatile organic compounds (VOCs)Properties

Most are hydrocarbons emitted by the leaves of many plants and methane

Organic compounds that evaporate easily, usually aromatic

Benzene Chlorofluorocarbons (CFCs

Sources Vehicles (largest source), evaporation of solvents

or fossil fuels, aerosols, paint thinners, dry cleaning

About two thirds of global methane emissions comes from human sources.

Other VOCs include industrial solvents such as trichlorethylene (TCE), benzene, gasoline, paint thinner, and vinyl chloride.

Effects Long-term exposure to benzene can cause cancer,

blood disorders, and immune system damage. eye and respiratory irritants Carcinogenic Liver, CNS, or kidney damage Damages plants Lowered visibility due to brown haze Global warming

Major Air PollutantsSulfur dioxide (SO2) Properties

colorless gas with irritating odor

Sources About one-third of SO2 in the

troposphere occurs naturally through the sulfur cycle.

Two-thirds come from human sources, mostly combustion (S+ O2 SO2) of sulfur-containing coal and from oil refining and smelting of sulfide ores, paper manufacture

Effects produces acid rain (H2SO4), breathing difficulties, eutrophication due to sulfate

formation (lichen and moss are indicators)

EPA Standard: 0.3 ppm (annual mean)

Major Air PollutantsOzone (O3)Properties

colorless, unpleasant odorhighly reactive gas major component of photochemical

smogSources

Created by sunlight acting on NOx and VOC

Photocopiers, chemical solventsCarsIndustryIncomplete fuel combustion products

EffectsLung irritantCause and aggravate respiratory illnessCan aggravate heart diseaseEyesDamage plants, rubber in tires, fabrics,

and paints0.1 ppm can lower PSN by 50%10,000 to 15,000 people in US admitted

to hospitals each year due to ozone-related illness

Children more susceptibleAirways narrowerMore time spent outdoors

Mobile Source Emissions: Mobile Source Emissions: Hydrocarbons – Precursors to Hydrocarbons – Precursors to OzoneOzone

Sunlight plus Cars Equals Photochemical Smog

Mexico City is one of the many cities in sunny, warm, dry climates with many motor vehicles that suffer from photochemical smog.

Sunlight plus Cars Equals Photochemical Smog

Photochemical smog is a mixture of air pollutants formed by the reaction of nitrogen oxides and volatile organic hydrocarbons under the influence of sunlight.

Clean Air Act of 1963Congress found: Most people now live in

urban areas Growth results in air

pollution Air pollution endangers

living things

It decided: Prevention and control at

the source was appropriate

Such efforts are the responsibility of states and local authorities

Federal funds and leadership are essential for the development of effective programs

Clean Air ActOriginally signed 1963

States controlled standards

1970 – Uniform Standards by Federal Govt.

Standards were stricterLimits on emissionsNew funding

Pollution control research

Citizens could sue Criteria Pollutants

Primary – Human health risk

Secondary – Protect materials, crops, climate, visibility, personal comfort

Clean Air Act1990 version

Strengthened regulations pertaining to air quality standards

Set nation wide standards for emissions of the six “criteria pollutants”

Left it up to the States to regulate and monitor

Emissions trading program introduced (Cap and Trade)

Total emissions have declined by 60% despite substantial increases in energy consumption, miles traveled by vehicles and gross domestic product

Clean Air Act1990 Policy changes

and developments Catalytic converters -

Required on all new U.S. autos since 1975

Scrubbers – use a combination of air and water that separates and removes particulates and SO2 before they are emitted from smokestacks

Leaded gasoline – phase out caused U.S. lead emissions to plummet by 93% in the 1980’s alone

Electrostatic precipitators – installed in smokestacks use an electrical charge to make particulates coalesce to that they can be physically removed

Clean Air Act1997 version

Reduced ambient ozone levels

Cost $15 billion/year -> save 15,000 lives

Reduce bronchitis cases by 60,000 per year

Reduce hospital respiratory admission 9000/year

Clean Air Act2007

U.S. Supreme Court ruled that carbon dioxide should be considered an air pollutant under the Clean Air Act

2009EPA proposed that

it should be considered an air pollutant at some point in the future

General Status of Global Air QualitySome pollutants are not

declining, some new air pollutants are emerging and green house gas emissions continue to rise

CO2 rose 44% from 1970 to 2008

Industrializing nations such a China and India are suffering increasing air pollution problems China has fueled its rapid

industrial development with its abundant reserves of coal.

Brown CloudRural issue – great deal of

air pollution emanates from feedlots (dust, methane, hydrogen sulfide, ammonia

South Asia’s Massive Brown CloudA huge dark brown

cloud of industrial smog, caused by coal-burning in countries such as China and India, stretches over much of southeastern Asia. In areas beneath the

cloud, photosynthesis is reduced interfering with crop development.

Fine particles and droplets in the cloud appear to be changing regional climates (including rainfall). May have contributed to

floods in 2002 and 2005 which killed thousands of people.

Hopefully Not The End