ch. 15 atmosphere

atmosphere

thin layer of gases that surround earth

relative humidity

ratio of water vapor the air contains to the maximum amount it could have at that temperature

air pressure

force exerted by air on the area below it

troposphere

lowest layer of the atmosphere

stratosphere

layer of the atmosphere above the troposphere

ozone layer

portion of the atmosphere found in the stratosphere that has concentrated ozone

mesosphere

layer that extends 50-80 km above sea level

thermosphere

top layer of the atmosphere that begins 80 km above the earth

radiation

transfer of energy through space

conduction

transfer of heat directly between two objects that are in contact with one another

convection

transfer of heat by the movement of currents within a fluid

convection current

sinking cool air and rising warm air

air pollution

release of damaging materials into the atmosphere

emissions

substances released into the atmosphere

fossil fuels

carbon-containing fuels that formed millions of years ago from living things

primary air pollutant

pollutants released directly into the troposphere

secondary air pollutant

harmful products produced when primary air pollutants react chemically with other substances

smog

unhealthy mixture of air pollutants that form over cities and nearby areas

Clean Air Act

law that protects and improves the quality of air in order to safeguard human health and the environment

catalytic converter

device in a motor vehicle that reduces the amount of air pollutants in emissions. changes carbon monoxide into carbon dioxide and water

scrubber

removes pollutants or changes them chemically before they leave factory smokestacks

ozone hole

area of lowered ozone concentration over Antarctica that occurs every year from August until October

chlorofluorocarbon (CFC)

family of chemical compounds containing chlorine, fluorine, and carbon

Montreal Protocol

a treaty that limits the production of chlorofluorocarbons