Clean Air Glossary

Acid: A sour solution with a pH of less than 7


Acid rain: A term referring to acid falling to earth in rain, snow, frost, fog, mist, gases, or dry particles.  Acid rain is caused when sulfur dioxide and nitrogen oxides emitted into the atmosphere become acid through chemical reactions and then fall to earth.



Air monitoring:  The measuring of the types and quantities of pollutants in the atmosphere



Air pollution: The presence of contaminants in the air in high enough concentrations to harm humans, wildlife, plants, or man-made things



Air Quality Index (AQI):   A scale developed by the government to measure how much pollution is in the air.  the AQI is often used in weather reports



Alkaline: A substance is alkaline when it has a pH higher than 7 (base) and is capable of neutralizing an acid



Atmosphere: The layer of air that surrounds the earth



Benzenes: Compounds found in motor fuels, dry cleaning processes, antifreeze, resins, perfumes, medicines, varnishes, lacquers, and solvents.  When evaporated, applied, spilled, or combusted, they emit hydrocarbons into the atmosphere which cases the creation of a harmful ozone



Buffer:  The ability to neutralize acidic or alkaline solutions in soil and water



Carbon dioxide: A colorless, odorless gas breathed out by humans and animals and emitted from burning fossil fuel



Carbon monoxide (CO): A colorless, odorless, deadly gas created mainly by the incomplete combustion of fuel in gasoline engines



Combustion: Burning; a chemical reaction that produces heath, light, and other by-products.  For example, in gasoline engines, when oxygen and gas mix and are ignited by a spark, heat, light, carbon monoxide, and water are produced



Criteria air pollutants: Common air pollutants that can be found throughout the United States



Emissions: Gases, vapors, and particles that go into the air, usually by human activities such as burning fossil fuels in vehicles, factories, power plants, and homes



Environment: Everything, living and non-living, on the earth



Fossil fuel: Buried deposits of decayed plants and animals that, over millions of years, have been converted to oil, coal, or natural gas by heat and pressure in the earth’s crust.  Fossil fuel provides most of our energy



Global warming: The possibility of earth’s temperature rising from excess carbon dioxide and other gases emitted from burning fossil fuels and other man-made sources



Groundwater: Water from rain and snow that seeps into the ground and is stored



Hazardous products: Products containing chemicals that can be poisonous or otherwise harmful to the environment



Hazardous waste: Solid and liquid waste that contains substances that can be harmful or dangerous to the environment



Hydrocarbons: Compounds produced by the incomplete burning of gasoline and the evaporation of such things as industrial solvents and oil paints. hydrocarbons contribute to smog and ozone



Lead (Pb): A metal added to some gasoline to improve engine performance.  As the engine runs, lead particles escape through the exhaust pipe.  Sources of lead include paint, metal refineries, and manufacturing of lead storage batteries



Natural resources: Things in nature that we use to make products and to live (for example: trees, oil, and water)



Nitrogen Oxides (NO and NO2): Gases produced during high temperature combustion in motor vehicles, power plants, and industrial furnaces



Nonattainment areas: A geographical area in which the level of air pollution is higher than the level allowed by state or federal standards



Ozone (O3): A harmful form of oxygen which is produced when sunlight stimulates a reaction between nitrogen oxides and hydrocarbons. Near the earth’s surface, ozone is a major component of smog. Also known as tropospheric ozone which extends from the earth’s surface up to 8 miles above the surface



Ozone layer: A layer of atmospheric gases, located in the stratosphere (9-30 miles above the earth’s surface). The ozone layer protects life on earth by filtering out harmful, cancer-causing ultraviolet radiation from the sun



Particulate: A tiny bit of solid or liquid matter (soot, dust, fumes, aerosols, mist, etc.) suspended or carried in the air.  Fine particulate matter smaller than 10 microns in diameter is called PM10.  One hair on your head is approximately 70 microns in diameter, so you see PM10 is really, really small



Pesticides:  A chemical used on food crops or other plants to kill bugs or other pests that damage them



pH: A scale numbered from 0 (acidic) to 14 (alkaline) and used to measure the degree of acidity or alkalinity in a substance



Pollutant: A harmful chemical emitted into the air, water, or soil.  Pollutants can be solid, liquid, or gas



Scrubber: An antipollution device that uses a spray to remove pollutants from a stream of air passing through a smokestack



Smelter: A plant where metals are melted to remove impurities



Smog: A mixture of emissions from fossil fuel, chemical vapors, and particles combined (hydrocarbons and nitrogen oxides) with sunlight and oxygen in the air.  Smog is mostly made up of ozone



Solvents: Industrial solvents are chemicals used in production processes. Examples include painting and coating automobiles, cleaning machined metal parts, printing and dry cleaning processes. Solvents create hydrocarbons which cause ozone



Stratospheric Ozone: Naturally occurring ozone (three oxygen molecules -O3) layer 9to 10 miles above the earth’s surface.  It protects us from the ultraviolet rays that can cause skin cancer, eye problems (cataracts), and can weaken our immune system



Sulfur dioxide (SO2): A gas, released mainly from power plants that burn coal and oil to make electricity



Ultraviolet radiation: Invisible waves of energy emitted from the sun



Volatile Organic Compounds (VOC’s): Are released from burning fuel (gasoline, oil, wood, coal, natural gas) solvents, paints, and glues. Cars are an important source of VOC’s

Comments are closed.