Geography 301 - Ch 13

Saginaw Valley State University

atmosphere

the layer of gases that envelopes our planet and performs many important functions like moderates our climate, provides, oxygen, shields us from meteors and hazardous solar radiation, and transports and recycles water and nutrients

• mostly nitrogen and oxygen, with smaller amounts of other gases, as well as water vapor

• 78% nitrogen and 21% oxygen

troposphere

part of the thermal layers; lowest 10-15 km of atmosphere; most weather occurs here

• the air we breathe; roughly 80% of atmospheres mass is here; experiences strong vertical mixing

stratosphere

part of the thermal layers; stagnant air; protective layer (ozone layer is there)

• much drier and less dense than the troposphere with very little vertical mixing

• warms the altitude due to absorption of sunlight by the ozone layer

• found between 12 and 50 km (7.5 and 30 mi) above Earth’s surface and has very few clouds and no storms

• air flows horizontally

• the highest concentration of ozone in the atmosphere and contains permanent temperature inversion

ozone layer

protects living organisms from UV damage from the sun

• located in the stratosphere

inversion

• temperature: a layer of cool air becomes trapped beneath warm air, preventing any vertical mixing from occurring; occurs often in valleys as nearby mountains block morning sunlight, creating cooler air in their shadow which traps pollution near the ground

• layer: the band of air where temperature rises with altitude

weather

specifies atmospheric conditions in a location over short time periods (weeks or shorter)

climate

patterns of atmospheric conditions in a location over long periods of time (years or longer)

primary pollutants

pollutants released directly from a source

• ash from volcanoes

• carbon monoxide from cars

secondary pollutants

primary pollutants that react with each other or components of the atmosphere

• ozone that is formed from pollutants in urban smog

The Clean Air Act

funds pollution control research, sets standards for air quality, and encourages emissions standards for automobiles and other point sources

• states are required to monitor emissions and develop, implement, and enforce their own regulations to comply with the law

Volatile Organic Compounds (VOCs)

carbon-containing chemicals emitted by vehicle engines and solvents

• methane, propane