criteria pollutants

the most common metallic air pollutant is

lead

worldwide air pollution efforts are least advanced in

major cities of developing countries

Carbon Monoxide

A colorless, odorless, toxic gas produced by incomplete fuel combustion. •Largest proportion produced by cars/trucks •Inhibits respiration by binding irreversibly to hemoglobin in the blood •Predominant form of carbon in the air is carbon dioxide, with levels increasing due to use of fossil fuels •One contributing factor to global warming

U.S. emissions total vs. Worldwide emissions total

Approximately 147 million metric tons of air pollutants are released annually into the atmosphere in the U.S. •Worldwide emissions total around 2 billion metric tons.

Air Pollution Trends in the U.S.

Air pollution in the U.S. has improved dramatically in the last decade. •The only pollutants that have not shown significant declines are particulates and nitrogen oxides. •80% of U.S. cities now meet National Ambient Air Quality Standards.

Plants and Air pollution

Chemical pollutants can directly damage plants or can cause indirect damage by reducing yields. •Certain environmental factors have synergistic effects in which the injury caused by the combination is more than the sum of the individual exposures.

Stratospheric Ozone Depletion (Ozone Hole)

Chlorofluorocarbons are the cause. •At ground-level, ozone is a pollutant, but in the stratosphere it screens UV radiation. •A 1% decrease in ozone could result in a million extra human skin cancers per year worldwide. •Decreased agricultural production and reduced plankton in the ocean, the basis of food chain

mercury

Dangerous neurotoxin •75% of human exposure comes from eating fish

Indoor Air Pollution

EPA found indoor concentrations of toxic air pollutants are often higher than outdoor. •People generally spend more time indoors. •Chloroform, benzene, and other chemicals in carpeting and paints in homes can be found at concentrations that would be illegal in the workplace.

Long-Range Transport

Fine aerosols can be carried great distances by the wind. •A 3 km toxic cloud covers India for most of year, causing 2 million deaths/yr. This cloud may also be disrupting monsoon rains on which harvests in South Asia depend •Increasingly, monitoring activity has begun to reveal industrial contaminants in places usually considered among the cleanest in the world (e.g., Antarctica). •Grasshopper transport - volatile compounds evaporate from warm areas; travel to poles where they condense and precipitate. Contaminants bioaccumulate in food webs. Whales, polar bears, & sharks have dangerously high levels of contaminants (such as HAP).

Effects of Air Pollution

Human Health (examples: Bronchitis, Emphysema)

sulfur Dioxide

Natural sources of sulfur in the atmosphere include evaporation from sea spray, volcanic fumes, and organic compounds. •Predominant form of anthropogenic sulfur is sulfur-dioxide from fossil-fuel combustion (coal and oil) and smelting of sulfide ores. •Sulfur dioxide is a corrosive gas which reacts with water vapor in the air to cause acid rain. •2/3 of total sulfur influx

Unconventional Pollutants

Noise, odor, light pollution

ozone

O3 •Ozone layer in the stratosphere shields the biosphere by absorbing uv radiation. •In the troposphere it is a pollutant: •A photochemical oxidant (product of secondary atmospheric reactions driven by solar energy) •Has an acrid, biting odor that is a characteristic photochemical smog

lead

One of many toxic metals that occur as trace elements in fuel, especially coal. •Lead is 2/3 of all metallic air pollution •Lead is a neurotoxin.

hazardes air pollutants

Require special reporting and management as they remain in ecosystems for a long period of time, and tend to accumulate in animal tissues. •Include carcinogens, neurotoxins, endocrine disrupters

Nitrogen Oxides

Reactive gases formed when nitrogen is heated above 650oC in the presence of oxygen, or when nitrogen compounds are oxidized by bacteria. •Nitric oxide is further oxidized to give nitrogen dioxide, the reddish brown gas in smog. •Nitrous oxide is an important greenhouse gas. •Nitrogen oxides combine with water to make the nitric acid found in acid rain (along with sulfuric acid discussed earlier). •Excess nitrogen from runoff of fertilizers causes eutrophication of inland waters and coastal seas. This encourages the growth of weeds that crowd out native species. •Humans are responsible for 60% of emissions.

Reducing Air Pollution (Conservation, Particulate Removal

Reducing Production •Conservation - by reducing electricity consumption, insulating buildings, and providing energy-saving public transportation •Particulate Removal Remove particles physically by trapping them in a porous mesh which allows air to pass through but holds back solids.

6 major criteria pollutants

Sulfur Dioxide •Nitrogen Oxides •Carbon Monoxide •Ozone •Lead •Particulates

Air Pollution Control

Sulfur Removal •Switch from soft coal with a high sulfur content to low sulfur coal. •Change to another fuel (natural gas). •Nitrogen Oxides •Best method is to prevent creation •Staged Burners

Cap & Trade

begun in 1990,set maximum amounts for pollutants, but let facilities facing costly cleanups pay others with lower costs to reduce emissions on their behalf. •Has worked well for sulfur dioxide •However, it permits local hot spots where high polluters continue to pollute, because they are paying someone somewhere else to reduce pollution.

criteria pollutants are those that

contribute the most to air quality degradation

secondary pollutants

converted to a hazardous form after entering the air and mixing with other air components

Acid precipitation

deposition of wet acidic solutions or dry acidic particles from the air

Fugitive Emissions

do not go through smokestack

an irreversible obstructive lung disease is called

emphysema

the us government agency responsible for reglationg air pollution is thr

environmental protection agency

Electrostatic Precipitator

fly ash particles pick up electrostatic charge as they pass between large electrodes in waste stream, and accumulate on collecting plate

los agnelgous has especially bad inversion problems because it

it is in a warm climate abd is partly ringed by mountains

pollutants such as chlofuricarbons deplete atmospheric

ozone

Montreal Protocol (1987)

phased out use of CFCs. HCFCs were substituted, which release less chlorine. •Very successful - CFCs cut by 95% since 1988. •Levels should be back to normal by 2049

CFCs (chlorofluorocarbons

release chlorine and fluorine in the stratosphere, which deplete ozone layer

primary pollutants

released directly from the source

Aerosol

solid particles or liquid droplets suspended in the atmosphere •atmospheric aerosols are usually called particulate material •includes ash, soot, lint, smoke, pollen, spores, etc

fugitive emmisions are produced by

strip mining, rock crushing, and other dust-producing activities

dust

strip mining, rock crushing, destruction