Environmental Science Ch.19- Atmospheric Pollution

Industrial Smog

The grayish mixture of moisture, soot, and sulfurous compounds that occurs in local areas in which industries are concentrated and coal is the primary energy source.

Photochemical Smog

The brownish haze that frequently forms on otherwise clear, sunny days over large cities with significant amounts of automobile traffic. It results largely from sunlight-driven chemical reactions among nitrogen oxides and hydrocarbons.

Temperature Inversion

The weather phenomenon in which a layer of warm air overlies cooler air near the ground and prevents the rising and dispersion of air pollutants.

Atmospheric Brown Cloud (ABC)

A 1-3km thick blanket of pollution that frequently sits over south and central Asia, made up of black carbon and soot from biomass and fossil fuel burning.

Volatile Organic Compounds (VOCs)

A category of major air pollutants present in the air in the vapor state. The category includes fragments of hydrocarbon fuels from incomplete combustion and evaporated organic compounds such as paint solvents, gasoline, and cleaning solutions. Volatile organic compounds are major factors in the formation of photochemical smog.

Carbon Monoxide

A highly poisonous gas, the molecules of which consist of a carbon atom with one oxygen attached. Not to be confused with carbon dioxide, a natural gas in the atmosphere.

Nitrogen Oxides

A group of nitrogen-oxygen compounds formed when some of the nitrogen gas in the air combines with oxygen during high-temperature combustion.

Nitrogen oxides are a major category of air pollutants and along with hydrocarbons, are a primary factor in the production of ozone and other photochemical oxidants that are the most harmful components of photochemical smog. Nitrogen oxides also contribute to acid precipitation.

Sulfur Dioxide

A major air pollutant and toxic gas formed as a result of burning sulfur. The major sources are burning coal that contains some sulfur and refining metal ores that contain sulfur.

Lead

One of the heavy metal pollutants, lead was once added to gasoline to improve combustion. It is toxic in very small quantities and has been removed from all but aviation gasoline.

Air Toxics

A category of air pollutants that includes radioactive materials and other toxic chemicals that are present at low concentrations but are of concern because they often are carcinogenic.

Primary Air Pollutants

Pollutants released directly into the atmosphere, mainly as a result of burning fuels and wastes, as opposed to secondary air pollutants.

Secondary Air Pollutants

Air pollutants resulting from reactions of primary air pollutants resident in the atmosphere. Secondary air pollutants include ozone, other reactive organic compounds, and sulfuric and nitric acids.

Ozone

A gas, O3, that is a secondary air pollutant in the lower atmosphere but that is necessary to screen out ultraviolet radiation in the stratosphere. May also be used for disinfecting water.

Peroxyacetyl Nitrates

A group of compounds [resent in photochemical smog that are extremely toxic to plants and irritating to the eyes, nose, and throat membranes of humans.

Sulfuric Acid

The major constituent of acid precipitation. Formed when sulfur dioxide emissions react with water vapor in the atmosphere.

Nitric Acid

A secondary air pollutant and a major component of acid deposition, nitric acid is produced when NOx in the air reacts with the hydroxyl radical and water.

Photochemical Oxidants

A major category of secondary air pollutants, including ozone, that are formed as a result of interactions between nitrogen oxides and hydrocarbons driven by sunlight.

Acid Deposition

Any form of acid precipitation and also fallout of dry acid particles.

Acid

Any compound that releases hydrogen ions when dissolved in water. Also, a water solution that contains a surplus of hydrogen ions.

Base

Any compound that releases hydroxyl ions when dissolved in water. A solution that contains a surplus of hydroxyl ions.

pH

The scale used to designate the acidity or basicity of solutions or soil, expressed as the logarithm of the concentration of hydrogen ions. pH 7 is neutral; values decreasing from 7 indicate increasing acidity, and values increasing from 7 indicate increasing basicity. Each unit from 7 includes a tenfold increase over the preceding unit.

Acid Precipitation

Includes acid rain, acid fog, acid snow, and any other form of precipitation that is more acidic than normal. Excess acidity is derived from certain air pollutants namely, sulfur dioxide and oxides of nitrogen.

Chronic Obstructive Pulmonary Disease (COPD)

A progressive lung disease that makes it hard to breath, involving three syndromes: asthma, bronchitis, and emphysema.

Acid Neutralizing Capacity (ANC)

In a water body, the capacity to neutralize acids due to the presence of buffer chemicals in solution.

Benzene

An organic chemical present in crude and refined oil products and tobacco smoke; a known human carcinogen.

Air Pollution Control Act

Federal legislation introduced in 1955 that was the first attempt to bring air pollution under control.

Clean Air Act Amendments of 1970 (CAA)

Amended in 1977 and 1990, the act is the foundation of US air pollution control efforts.

Ambient Standards

Air-quality standards (set by the EPA) determining certain levels of pollutants that should not be exceeded in order to maintain environmental and human health.

Criteria Pollutants

Certain pollutants whose levels are used as a gauge for the determination of air (or water) quality.

National Ambient Air Quality Standards (NAAQS)

The allowable levels of ambient criteria air pollutants set by EPA regulation.

National Emission Standards for Hazardous Air Pollutants (NESHAPs)

The standards for allowable emissions of certain toxic substances.

Command and Control Strategy

The basic strategy behind most public policy having to do with air and water pollution. The strategy involves setting limits on pollutant levels and specifying control technologies that must be used to achieve those limits.

Reasonable Available Control Technology (RACT)

Applied to the goals of the Clean Air Act, EPA approved forms of technology that will reduce the output of industrial air pollutants.

Maximum Achievable Control Technology (MACT)

The best technology available for reducing the output of especially toxic industrial pollutants.

Mercury and Air Toxics Standards

Rules published by the EPA in 2011 that require all coal-and oil-fired power plants to limit their emissions of mercury and other toxic pollutants; industries have four years to comply with the rules.

Catalytic Converter

The device used by vehicle manufacturers to reduce the amounts of carbon monoxide, hydrocarbons, and nitrogen oxides in a vehicle’s exhaust. The converter contains catalysts that change these compounds to less harmful gases as the exhaust passes through.

Energy Independence and Security Act of 2007

Legislation establishing energy policy by emphasizing demand-side policies such as conserving energy and using renewable energy sources.

Hybrid Electric Vehicle

An automobile combining a gasoline motor and a battery-powered electric motor that produces less pollution and gets higher gasoline mileage than do conventional gasoline-powered vehicles.

Clean Air Interstate Rule (CAIR)

EPA rule published in 2005 establishing cap-and-trade programs for sulfur dioxide and nitrogen oxides in 28 eastern states.

Cross State Air Pollution Rule (CSAPR)

The ruling by the EPA that replaces the Clean Air Interstate Rule, requiring reductions in NOx and SO2 to aid states in the East to achieve ozone and particulate matter reductions.

Cap-and-trade System

A form of market-based environmental policy that sets a maximum level of pollutant (the cap), distributes pollution permits, and allows industries to trade permits to achieve their allowable pollution.

Chlorofluorocarbons (CFCs)

Synthetic organic molecules that contain one or more of both chlorine and fluorine atoms and that are known to cause ozone destruction.

Chlorine Catalytic Cycle

In the stratosphere, a cyclical chemical process in which chlorine monoxide breaks down ozone.

Catalyst

A substance that promotes a given chemical reaction without itself being consumed or changed by the reaction. Enzymes are catalysts for biological reactions. Also, catalysts are used in some pollution control devices.

Montreal Protocol

An agreement made in 1987 by a large group of nations to cut back the production of chlorofluorocarbons in order to protect the ozone shield. A 1990 amendment called for the complete phaseout of these chemicals by 2000 in developed nations and by 2010 in less developed nations.