Unit 6 vocabulary

acid deposition
The falling of acids and acid-forming compounds from the atmosphere to the earth’s surface.
air pollution
One or more chemicals in high enough concentrations in the air to harm humans, other animals, vegetation, or materials.
Increase in concentration of DDT, PCBs, and other slowly degradable, fat-soluble chemicals in organisms at successively higher trophic levels of a food chain or web.
a former industrial or commercial site where future use is affected by real or perceived environmental contamination.
Substance that can react with hydrogen ions in a solution and thus hold the acidity or pH of a solution fairly constant. .
carbon monoxide
a colorless, odorless, highly toxic gas that forms during the incomplete combustion of carbon-containing materials.
chlorofluorocarbons (CFCs)
Organic compounds made up of atoms of carbon, chlorine, and fluorine. An example is Freon-12 (CCl2F2), used as a refrigerant in refrigerators and air conditioners and in making plastics such as Styrofoam. They can deplete the ozone layer when they slowly rise into the stratosphere and their chlorine atoms react with ozone molecules.
Dichlorodiphenyltrichloroethane, a chlorinated hydrocarbon that has been widely used as an insecticide but is now banned in some countries.
Family of 75 different chlorinated hydrocarbon compounds formed as unwanted by-products in chemical reactions involving chlorine and hydrocarbons, usually at high temperatures.
The amount of a potentially harmful substance an individual ingests, inhales, or absorbs through the skin.
dose-response curve
Plot of data showing effects of various doses of a toxic agent on a group of test organisms.
old, end-of-life or discarded appliances using electricity. It includes computers, consumer electronics, fridges etc which have been disposed of by their original users.
Study of the patterns of disease or other harmful effects from toxic exposure within defined groups of people to find out why some people get sick and some do not.
hazardous waste
Any solid, liquid, or containerized gas that can catch fire easily, is corrosive to skin tissue or metals, is unstable and can explode or release toxic fumes, or has harmful concentrations of one or more toxic materials that can leach out. See also toxic waste.
industrial smog
Type of air pollution consisting mostly of a mixture of sulfur dioxide, suspended droplets of sulfuric acid formed from some of the sulfur dioxide, and a variety of suspended solid particles.
integrated waste management
Variety of strategies for both waste reduction and waste management to deal with solid wastes.
the amount of a material, given all at once, which causes the death of 50% (one half) of a group of test animals. It is one way to measure the short-term poisoning potential (acute toxicity) of a material.
median lethal dose (LD50)
Amount of a toxic material per unit of body weight of test animals that kills half the test population in a certain time.
nitric acid (HNO3)
Formed when NO2 reacts with water vapor in the air. It is a component of acid deposition that returns to the earth and can damage trees, soils, and aquatic life in lakes.
nitrogen oxides (NOx)
These gases play a role in photochemical smog and can irritate the eyes, nose, throat, and lungs; aggravate asthma and bronchitis; and increase susceptibility to respiratory infections by impairing the immune system. They can also suppress plant growth and reduce visibility when they are converted to nitric acid and nitrate salts.
nonpoint source
Large or dispersed land areas such as crop fields, streets, and lawns that discharge pollutants into the environment over a large area.
ozone (O3)
Colorless and highly reactive gas; a major component of photochemical smog and also found in the stratosphere where it protects life by filtering out most harmful UV radiation from the sun.
ozone layer
Layer in the stratosphere that protects life on earth by filtering out most harmful ultraviolet radiation from the sun.
Solid particles and liquid droplets small and light enough to remain suspended in the air for short to long periods. Also referred to as suspended particulate matter (SPM).
photochemical smog
Complex mixture of air pollutants produced in the lower atmosphere by the reaction of hydrocarbons and nitrogen oxides under the influence of sunlight. Especially harmful components include ozone, peroxyacyl nitrates (PANs), and various aldehydes.
point source
Single identifiable source that discharges pollutants into the environment. Examples are the smokestack of a power plant or an industrial plant, drainpipe of a meatpacking plant, chimney of a house, or exhaust pipe of an automobile.
polychlorinated biphenyls (PCBs)
Group of 209 different toxic, oily, synthetic chlorinated hydrocarbon compounds that can be biologically amplified in food chains and webs.
primary pollutant
Chemical that has been added directly to the air by natural events or human activities and occurs in a harmful concentration.
radon (Rn)
Naturally occurring colorless and odorless radioactive gas found in some types of soil and rock. It can seep into homes and buildings sitting above such deposits. Long-term exposure can cause lung cancer, especially among smokers.
See dose, dose-response curve, median lethal dose.
sanitary landfill
Waste disposal site on land in which waste is spread in thin layers, compacted, and covered with a fresh layer of clay or plastic foam each day.
secondary pollutant
Harmful chemical formed in the atmosphere when an air pollutant reacts with normal air components or other air pollutants.
Originally a combination of smoke and fog but now used to describe other mixtures of pollutants in the atmosphere.
sulfur dioxide (SO2)
Colorless gas with an irritating odor. About two-thirds (and as high as 90% in urban areas) comes from human sources, mostly combustion of sulfur-containing coal in electric power and industrial plants and from oil refining and smelting of sulfide ores.
sulfuric acid (H2SO4)
Formed in the atmosphere as microscopic suspended droplets, it is a component of acid deposition.
a United States federal government program designed to fund the cleanup of sites contaminated with hazardous substances and pollutants. It was established as the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA).
temperature inversion
Layer of dense, cool air trapped under a layer of less dense, warm air. This prevents upward-flowing air currents from developing. Air pollution in the trapped layer may build up to harmful levels.
Measure of how harmful a substance is.
Study of the adverse effects of chemicals on health.
volatile organic compounds (VOCs)
Organic compounds that exist as gases in the air. Most are hydrocarbons.