Principles of Environmental Science Inquiry and Appications9


The physical conditions of the atmosphere

(moisture, temperature, pressure, and wind)

A description of the long-term pattern of weather in a particular area. 
Minute particles or liquid droplets suspended in the air. 
The layer of air nearest to the earth’s surface; both temperature and pressure usually decrease with increasing altitude. 
Convection Currents
Rising or sinking air currents that stir the atmosphere and transport heat from one area to another. Convection currents also occur in water. 



A highly reactive molecule containing three oxygen atoms; a dangerous pollutant in ambient

air. In the stratosphere, however, ozone forms an ultraviolet absorbing shield that protects us from mutagenic radiation. 

The zone in the atmosphere extending from the tropopause to about 50 km (30 mi) above the earth’s surface; temperatures are stable or rise slightly with altitude; has very little water vapor but is rich in ozone. 
A description of a surface’s reflective properties. 


Greenhouse Effect 


Trapping of heat by the earth’s atmosphere, which is transparent to incoming visible light waves but absorbs outgoing longwave infrared radiation. 

Latent Heat

Stored energy in a form that is not

sensible (detectable by ordinary senses).

Thermohaline Circulation 
A large-scale oceanic circulation system in which warm water flows from equatorial zones to higher latitudes where it cools, evaporates, and becomes saltier and more dense, which causes it to sink and flow back toward the equator in deep ocean currents. 

Milankovitch Cycles


Periodic variations in tilt,

eccentricity, and wobble in the earth’s orbit; Milutin Milankovitch suggested these are responsible for cyclic weather changes. 

El Nino

A climatic change marked by shifting of a large warm water pool from the western Pacific Ocean toward the east. Wind direction and precipitation patterns are changed over much of the Pacific and perhaps around

the world.

Southern Oscillation 
The combination of El Nino and La Nina cycles. 
La Nina
The opposite of El Nino.
Intergovernmental Panel on Climate Change (IPCC) 
A large group of scientists from many nations and a wide variety of fields assembled by the United Nations Environment Program and World Meteorological Organization to assess the current state of knowledge about climate change. 
Kyoto Protocol
An international treaty adopted in Kyoto, Japan, in 1997, in which 160 nations agreed to roll back CO2, methane, and nitrous oxide emissions to reduce the threat of global climate change. 
Carbon Neutral 
Producing no net carbon dioxide emissions. 

Carbon Management

Projects to reduce carbon

dioxide emissions from fossil fuel or to

ameliorate their effects.

Point Sources
Specific locations of highly concentrated pollution discharge, such as factories, power plants, sewage treatment plants, underground coal mines, and oil wells. 
Primary Pollutants
Chemicals released directly into the air in a harmful form. 
Photochemical Oxidants
Products of secondary atmospheric reactions. See also smog. 
The combination of smoke and fog in the stagnant air of London; now often applied
to photochemical pollution. 


Fugitive Emissions


Substances that enter the air without going through a smokestack, such as dust from soil erosion, strip mining, rock crushing, construction, and building demolition. 

Nonpoint Sources 


Scattered, diffuse sources of

pollutants, such as runoff from farm fields, golf

courses, and construction sites. 

Conventional (Criteria) Pollutants

The seven substances (sulfur dioxide, carbon monoxide, particulates, hydrocarbons, nitrogen oxides, photochemical oxidants, and lead) identified by the Clean Air Act as the most serious threat of all pollutants to human health

and welfare.

Ambient Air 
The air immediately around us.    

Unconventional Pollutants


Toxic or hazardous substances, such as asbestos, benzene, beryllium, mercury, polychlorinated biphenyls, and vinyl chloride, not listed in the original Clean Air Act because they were not released in large quantities; also called noncriteria pollutants. 

Sulfur Dioxide 
A colorless, corrosive gas directly damaging to both plants and animals. 
Nitrogen Oxides
Highly reactive gases formed when nitrogen in fuel or combustion air is heated to over 650°C (1,200°F) in the presence of oxygen or when bacteria in soil or water oxidize nitrogen-containing compounds. 

Carbon Monoxide


Colorless, odorless, nonirritating

but highly toxic gas produced by incomplete combustion of fuel, incineration of biomass or solid waste, or partially anaerobic decomposition of organic material. 

Particulate Material 


Atmospheric aerosols, such

as dust, ash, soot, lint, smoke, pollen, spores, algal cells, and other suspended materials; originally applied only to solid particles but now extended to droplets of liquid. 

Volatile Organic Compounds
Organic chemicals that evaporate readily and exist as gases in the air. 
Chemical compounds with a carbon skeleton and one or more attached chlorine and fluorine atoms. Commonly used as refrigerants, solvents, fire retardants, and blowing agents. 
Temperature Inversions
Atmospheric conditions in which a layer of warm air lies on top of cooler air and blocks normal convection currents. This can trap pollutants and degrade air quality. 
Heat Islands
Areas of higher temperatures around cities. 
Dust Domes
High concentrations of dust and aerosols in the air over cities. 
Synergistic Effects 
The combination of several processes or factors is greater than the sum of their individual effects. 
Acid Precipitation 
Acidic rain, snow, or dry particles deposited from the air due to increased acids released by anthropogenic or natural resources. 

New Source Review 


A permitting process required

by 1977 amendments to the Clean Air Act, required when industries expand or modify facilities. The rule is contentious because vague language in the law allows industries to avoid oversight.