chapter 3 Flashcards
What is the absolute height of the atmosphere above earth’s surface?
- The absolute height of the earth’s atmosphere is 10,000 kilometres (6000 miles).
How did Earths atmosphere develop?
- Our modern atmosphere, therefore, was significantly influenced by life on Earth. Processes such as photosynthesis by bacteria, terrestrial plants and other organisms that emitted oxygen while taking in carbon dioxide.
Permanent gases: nitrogen and oxygen (each is what ? of the atmospheric volume?)
- Nitrogen makes up more than 78 percent of the total, and oxygen nearly 21 percent.
How does oxygen originate in the atmosphere?
Oxygen is produced by vegetation and is removed by a variety of organic and inorganic processes
Nitrogen’s source?
- Nitrogen is added to the air by the decay and burning of organic matter, volcanic eruptions, and the chemical breakdown of certain rocks
Variable gases:
water vapor, carbon dioxide, ozone, other variable gases. Cover only a tiny portion of the atmosphere yet they have great control over the environment. In earths lower atmosphere, the typical percentage of water capor in dry air ranges from 0-4%.
What is the concentration of carbon dioxide? What is the significance of this gas?
- The proportion of carbon dioxide in the atmosphere has increased at a rate of more than 0.0002 percent (2 parts per million) per year and at present is about 401 parts per million
- Most atmospheric scientists conclude that the increased levels of CO2 are causing the lower atmosphere to warm enough to produce significant, although still somewhat unpredictable, global climatic changes.
What are Particulates? (Aerosols)
- The solid and liquid particles found in the atmosphere are collectively called particulates or aerosols.
Troposphere – what is most significant about this layer?
- The lowest layer of the atmosphere—the one in contact with Earth’s surface
What happens to air temperature when rising through the troposphere?
- Within the troposphere, temperature generally decreases with increasing altitude
Why doesn’t the atmosphere float away from Earth? Why doesn’t it collapse? What happens to atmospheric pressure with increasing altitude? Why?
- For simplicity’s sake, we can think of atmospheric pressure as the “weight” of the overlying air.
What is Ozone? Where does it come from? Where is the Ozone Layer? What are CFCs?
- The ozone layer lies between 15 and 48 kilometers (9 and 30 miles) up. It is sometimes referred to as the stratospheric ozone layer because it is centered in the lower stratosphere
What’s the “hole” in the Ozone Layer?
- the dramatic thinning of the ozone layer observed since the 1970s is due primarily (if not entirely) to the release of human-produced chemicals.
What was the 1987 Montreal Protocol
- timetables for phasing out the production of the major ozone-depleting substances
Primary pollutants are emitted directly from a source. Carbon Monoxide, Nitrogen / Sulfur compounds are significant pollutants. Why?
- By far the greatest contributors are associated with cities, where people and activities are concentrated, and particularly from internal combustion engines and industrial processes