AP Environmental Science 2013-2014

AIR POLLUTION NOTES

Reduction of visual range and atmospheric clarity

GENERAL EFFECTS OF AIR POLLUTION

Harmful to health (damages plants, lung disease, cancer, birth defects, eye and respiratory system irritation, greater susceptibility to heart disease, aggravation of asthma and emphysema)

Synergistic effects—ex. sulfate and nitrate may attach to small particles in the air, making it easier for them to penetrate deeper into lung tissue

Subsequent pollution of water and soil

Stationary sources have a relatively fixed location and include point sources, fugitive sources, and area sources. Point sources emit pollutants from one or more

controllable sites, such as power-plant smokestacks.

SOURCES OF AIR POLLUTION

Fugitive sources generate air pollutants from open areas exposed to wind. Examples include burning for agricultural purposes, as well as dirt roads, construction sites, farmlands, storage piles, surface mines, and other exposed areas.

SOURCES OF AIR POLLUTION

Area sources are well-defined areas that contain several sources of air pollutants. Examples include urban complexes and agricultural areas.

SOURCES OF AIR POLLUTION

Mobile sources of air pollution include automobiles, aircraft, ships, trains, and anything else that pollutes as it moves from place to place.

SOURCES OF AIR POLLUTION

Primary pollutants are emitted directly into the air. Ex. particulates, SO2, CO, NOx, hydrocarbonsThe primary pollutants that account for nearly all air pollution problems are CO (58%), VOCs (11%), NOx (15%), SOx (13%), and particulates (3%)

Secondary pollutants are produced by reactions between primary pollutants and normal atmospheric compounds. Ex. ozone

PRIMARY AND SECONDARY POLLUTANTS

The six most common classes of pollutants; the EPA has set specific limits on the levels of these compounds

CRITERIA POLLUTANTS

Description: Colorless, odorless gas normally present at Earth’s surface in low concentrationsMajor Anthropogenic Source(s): Burning of fossil fuels (particularly coal), production of paper/cement,/aluminumAdverse Effects: Lung damage, precursor to acid rain, corrosion of paint and metals

SULFUR DIOXIDE, SO2

Description: NO2 is a brownish gasMajor Anthropogenic Source(s): Automobiles, burning of fossil fuelsAdverse Effects: Contribute to smog and acid rain; eutrophication; respiratory irritation

NITROGEN OXIDES, NOX

Description: Colorless, odorless gas; extremely toxic even at low concentrationsMajor Anthropogenic Source(s): Incomplete combustion (fires, automobiles, etc.)Adverse Effects: Asphyxiation, birth defects

CARBON MONOXIDE, CO

Description: Special form of oxygen, not as stable as O2; “good up high, bad nearby”Major Anthropogenic Source(s): Automobiles and industrial processes (secondary pollutant)Adverse Effects: Causes injury to living things, especially in respiratory system

OZONE, O3

Description: Tiny particlesMajor Anthropogenic Source(s): Pretty much all industrial processes, farmingAdverse Effects: Can be released into bloodstream; linked to lung cancer, bronchitis; interfere with photosynthesis

PARTICULATES

Description: Heavy metalMajor Anthropogenic Source(s): Car exhaust (not anymore…)Adverse Effects: Toxic to wildlife and people

LEAD

Pollutants known or suspected to cause cancer and other serious health problems after either long-term or short-term exposure—more than 150 are knownHydrogen sulfide, H2S

Highly toxic corrosive gas with a rotten-egg odor Emitted from geysers, swamps, and bogs; also

petroleum refineries and metal smeltersHydrogen fluoride, HF

Extremely toxic; in aqueous solution, it can etch glass

Produced through aluminum production and processing/burning of fossil fuels

AIR TOXICS

Mercury, HgHeavy metal released into air by burning of coal and mining, as well as volcanic eruptions

VOCs (hydrocarbons)Largest source = automobiles

AIR TOXICS

Benzene, C6H6Gasoline additive and industrial solvent; component of cigarette smoke

AIR TOXICS

Sulfur dioxideTechnology that “cleans up coal”, switching from high-sulfur to low-sulfur coal, washing coal, coal gasification; in power plants, a process called scrubbing removes sulfur from flue gas after the coal is burned

CONTROLLING COMMON POLLUTANTS

Carbon monoxide, nitrogen oxides, hydrocarbonsAutomobile emissions standards/catalytic converters; converts CO to CO2 and hydrocarbons to CO2 and water

NOx are reduced by recirculating exhaust gases inside automobiles

CONTROLLING COMMON POLLUTANTS

ParticulatesSettling chambers can be used to control emissions of coarse particulates from power plants and industrial sites by letting particles settle in a location where they can be collected and disposed of in landfills

CONTROLLING COMMON POLLUTANTS