AP Environmental Science Chapter 19 Vocab
nitrogen monoxide (NO)
A by-product of combustion of substances in the air that can be released by automobile engines. Effects include acid deposition and photochemical smog. Also known as nitric oxide.
secondary pollutant
A chemical formed in the atmosphere when a primary air pollutant reacts with normal air components or other air pollutants and occurs at a harmful concentration level. Ex.: H2SO4, ozone, PANs.
nitrogen dioxide (NO2)
A chemical that can be created when N2 reacts with O2 at the high temperatures created by combustion engines. Effects include acid deposition and photochemical smog.
primary pollutant
A chemical that has been added directly to the air by natural events or human activities and occurs at a harmful concentration level. Ex.: NO, CO2, soot.
ozone (O3)
A colorless and highly reactive gas that filters out UV radiation in the stratosphere and is a major component of photochemical smog in the troposphere.
sulfur dioxide (SO2)
A 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 (S2−) ores. In the atmosphere, SO2 can be converted into microscopic suspended droplets of sulfuric acid (H2SO4) and suspended particles of sulfate salts that return to the earth as a component of acid deposition.
carbon dioxide (CO2)
A colorless, odorless greenhouse gas that contributes heavily to global warming.
carbon monoxide (CO)
A colorless, odorless, highly toxic gas that forms during the incomplete combustion of carbon-containing materials. Vehicles account for 78% of emissions. Carbon monoxide leads to ozone formation and can bind to hemoglobin, suffocating cells.
photochemical smog
A complex mixture of air pollutants produced in the troposphere by the reaction of hydrocarbons and nitrogen oxides under the influence of sunlight. Because it is produced by photochemical reactions, this form of smog is most dangerous on hot, sunny, windless days. Photochemical smog often produces a brownish haze. Especially harmful components include ozone, peroxyacyl nitrates (PANs), and various aldehydes.
clean coal
A concept for processes or approaches that mitigate emissions of carbon dioxide (CO2) and other greenhouse gases that arise from the utilization of coal, mainly for electrical power generation, using clean coal technology. Currently, the term clean coal is used in the coal industry primarily in reference to carbon capture and storage, which pumps and stores CO2 emissions underground, and plants using integrated gasification combined cycle (IGCC). IGCC involves coal gasification, which provides a basis for increased efficiency and lower cost in capturing CO2 emissions.
dust mite
A cosmopolitan pyroglyphidae that lives in human habitation. Allergens, such as Der p 1, produced by house dust mites are among the most common triggers of asthma.
ozone depletion
A decrease in concentration of ozone (O3) in the stratosphere; generally refers to the decrease caused by chlorofluorocarbons (CFCs) prior their being regulated and ultimately phased out.
wet scrubber
A device used to redice SO2 emissions in which fine mists of water vapor trap particulates. SO2 passing through a watery mixture (slurry) of lime (CaO) or limestone (CaCO3) is converted to a calcium sulfite (CASO3) sludge that is collected and disposed of at a landfill. Ineffective at removing hazardous fine and ultrafine particles. Wet scrubbers reduce pollutants at the output stage.
electrostatic precipitator
A device used to reduce NOx and SO2 emissions in which the positively-charged walls of the precipitator attract negatively-charged particulates, which then fall off the wall into a collector; ineffective at removing hazardous ultrafine particles. Electrostatic precipitators reduce pollutants at the output stage.
lead (Pb)
A heavy metal particulate that bioaccumulates and can cause nervous system damage. In developed nations, sources include metal smelting. In developing nations, sources include leaded gasoline.
temperature inversion
A layer of dense, cool air trapped under a layer of less dense, warm air. It prevents upward-flowing air currents from developing. In a prolonged inversion, air pollution in the trapped layer may build up to harmful levels.
tropospheric ozone
A major component of photochemical smog produced by a reaction involving NOx. It can cause respiratory problems, weaken the immune system, aggravate heart disease, and damage plants, rubber, fabrics, and paints.
nitrous oxide (N2O)
A major greenhouse gas.
secondary standard
A national ambient air quality standard designed to prevent environmental and property damage.
primary standard
A national ambient air quality standard designed to protect human health.
radon (Rn)
A 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. Radon accounts for 55% of radiation exposure for the average U.S. citizen.
fluidized-bed combustion
A process that reduces coal emissions at the input stage by blowing hot air into a boiler to burn a mixture of powdered coal and crushed limestone. Fluidized-bed combustion reduces pollutant emissions and burns coal more efficiently, but it is also costly.
coal gasification
A process that reduces coal emissions at the input stage by producing syngas, a combustible fuel gas mixture, from coal, water, air and/or oxygen.
emissions trading (cap-and-trade) program
A program that enables the 110 most polluting power plants in 21 states to buy and sell SO2 pollution rights.
sulfuric acid
A secondary pollutant created when SO2 in the atmosphere is oxidized into SO3 and then combined with water (H2O).
asbestos
A set of six naturally occurring silicate minerals[1] which all have in common their eponymous asbestiform habit: long (roughly 1:20 aspect ratio), thin fibrous crystals, with each visible fiber composed of millions of microscopic "fibrils" that can be released by abrasion and other processes. Asbestos was once used widely for a variety of construction purposes, including insulation, fireproofing, roofing, tiling, and more. Asbestos may cause cancer of the lungs, especially mesothelioma, a rare cancer of the mesothelium, a membrane that protects many of the body's internal organs.
sick building syndrome (SBS)
A term used to describe situations in which building occupants experience acute health and comfort effects that appear to be linked to time spent in a building, but no specific illness or cause can be identified. A 1984 World Health Organization report suggested up to 30% of new and remodeled buildings worldwide may be subject of complaints related to poor indoor air quality.
industrial smog
A type of air pollution consisting mostly of a mixture of sulfur dioxide (SO2), suspended droplets of sulfuric acid (H2SO4), and suspended solid particles.
1970 Clean Air Act
An act that set standards for air quality, including limits of emissions, and funded pollution control; amended in 1977.
1990 Clean Air Act
An act that strengthened controls on emissions, acid deposition, and ozone depletion and created transferable industry permits for SO2 emissions, for which the amount permitted decreased each year.
environmental tobacco smoke
An indoor air pollutant that can caused sudden infant death syndrome (SIDS), lower respiratory tract illness, middle ear disease, asthma, and other negative health effects.
aldehyde
An organic compound containing a formyl group. Ex.: formaldehyde, the simplest aldehyde. Also known as an alkanal.
carbon oxides
Carbon and oxygen compounds, including carbon monoxide (CO) and carbon dioxide (CO2).
atmospheric pressure
Force or mass per unit area of air.
nitrogen oxides
Nitrogen and oxygen compounds, including nitrogen oxide (NO) and nitrogen dioxide (NO2). These gases play a role in photochemical smog; 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 converted to nitric acid and nitrate salts.
chlorofluorocarbons (CFCs)
Organic compounds made up of carbon, chlorine, and fluorine. Gaseous CFCs can deplete the ozone layer when they slowly rise into the stratosphere and their chlorine atoms react with ozone molecules. Ex.: Freon-12 (CCl2F2), a substance that was once commonly used in refrigerators and air conditioning units, as well as in the production of plastics such as Styrofoam.
volatile organic compounds (VOCs)
Organic compounds that have a high vapor pressure at room temperature and thus exist as gases. Most are hydrocarbons. Volatile organic compounds are a component of both outdoor and indoor air pollution. They can combine with nitrogen dioxide to create PANs and aldehydes. Ex.: formaldehyde, which evaporates from paint.
PANs
Peroxyacyl nitrates; a group of chemicals found in photochemical smog.
particulates
Solid particles and liquid droplets small and light enough to remain suspended in the air for varying periods of time; a common component of industrial smog. Ex.: dust, soot, nitrates. Particles less than 10 micrometers in diameter (PM10) pose a health concern because they can be inhaled into and accumulate in the respiratory system. Particles less than 2.5 micrometers in diameter (PM2.5) are referred to as "fine" particles and are believed to pose the greatest health risks. Because of their small size (approximately 1/30th the average width of a human hair), fine particles can lodge deeply into the lungs. Also known as suspended particulate matter (SPM).
national ambient air quality standards (NAAQS)
Standards for air quality that are established by the EPA and determine the allowable quantities of six outdoor criteria pollutants (carbon monoxide, nitrogen oxides, sulfur dioxide, suspended particulate matter, ozone, and lead).
indoor air pollutants
Substances that contribute to poor indoor air quality and may lead to health problems or other undesirable effects. Ex.: nitrogen dioxide (NO2); carbon monoxide (NO); asbestos; volatile organic compounds (VOCs), including formaldehyde; allergens produced by dust mites; environmental tobacco smoke (ETS); fine particles; and radon (Rn).
acid deposition
The fall of acids and acid-forming compounds from the atmosphere to the Earth's surface. Acid deposition is commonly known as acid rain, a term that refers to the wet deposition of acids and acid-forming compounds.
1955 Air Pollution Control Act
The first United States Clean Air Act enacted by Congress to address the national environmental problem of air pollution, which left prevention and control of air pollution to the states but authorized the federal government to conduct research and disseminate information regarding air pollution.
troposphere
The innermost layer of the atmosphere, which contains 75% of the mass of Earth's air and extends about 17 kilometers (11 miles) above sea level.
ozone layer
The layer of gaseous ozone (O3) in the stratosphere that protects life on Earth by filtering out harmful UV radiation emitted by the sun.
air pollution
The presence in the atmosphere of one or more unnatural chemicals (or heat or noise) in concentrations high enough to harm humans, animals, vegetation, or materials.
stratosphere
The second innermost layer of the atmosphere, which extends about 17-48 kilometers above sea level. It contains small amounts of gaseous ozone (O3), which filters out about 95% of the incoming harmful ultraviolet (UV) radiation emitted by the sun.
