Earth's atmosphere
hideThe Earth's atmosphere is a layer of gases surrounding the planet Earth that is retained by the Earth's gravity. It has a mass of about five quadrillion metric tons. Dry air contains roughly (by volume) 78.08% nitrogen, 20.95% oxygen, 0.93% argon, 0.038% carbon dioxide, and trace amounts of other gases. Air also contains a variable amount of water vapor, on average around 1%. The atmosphere protects life on Earth by absorbing ultraviolet solar radiation, warming the surface through heat retention (greenhouse effect), and reducing temperature extremes between day and night.
There is no definite boundary between the atmosphere and outer space. It slowly becomes thinner and fades into space. An altitude of 120 km (75 mi) marks the boundary where atmospheric effects become noticeable during atmospheric reentry. The Kármán line, at 100 km (62 mi), is also frequently regarded as the boundary between atmosphere and outer space. Three quarters of the atmosphere's mass is within 11 km (6.8 mi; 36,000 ft) of the surface.
For more information about Earth's atmosphere, read the full article at
Wikipedia.
This text uses material from Wikipedia and is available under the GNU Free Documentation License.
News tagged with air
Barn personnel experience higher-than-average rates of respiratory symptoms
Nov 20, 2009 |
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The estimated 4.6 million Americans involved in the equine industry may be at risk of developing respiratory symptoms due to poor air quality in horse barns, according to a questionnaire study undertaken earlier this year ...
Braking news: Particles from car brakes harm lung cells
Nov 20, 2009 |
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Real-life particles released by car brake pads can harm lung cells in vitro. Researchers writing in BioMed Central's open access journal Particle and Fibre Toxicology found that heavy braking, as in an emergency stop, caused ...
Hidden threat: Elevated pollution levels near regional airports
Nov 18, 2009 |
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Scientists are reporting evidence that air pollution — a well-recognized problem at major airports — may pose an important but largely overlooked health concern for people living near smaller regional airports. ...
Glimpsing a greener future: Computer model foresees effects of alternative transportation fuels
Nov 16, 2009 |
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(PhysOrg.com) -- It's the year 2060, and 75 percent of drivers in the Greater Los Angeles area have hydrogen fuel cell vehicles that emit only water vapor.
Green heating and cooling technology turns carbon from eco-villain to hero
Nov 10, 2009 |
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Carbon is usually typecast as a villain in terms of the environment but researchers at the University of Warwick have devised a novel way to miniaturise a technology that will make carbon a key material in ...
Path to good health, less pollution is the sidewalk: report
Nov 09, 2009 |
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US pressure groups joined forces Monday to urge authorities to spend more to improve Americans' health and cut greenhouse gas emissions.
States call on EPA for tougher air pollution regulations
Nov 06, 2009 |
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Twelve states and the District of Columbia urged the Environmental Protection Agency Thursday to adopt more rigorous national policies so they can meet federal air pollution reduction requirements for the region.
Air pollution increases infants' risk of bronchiolitis
Nov 06, 2009 |
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Infants who are exposed to higher levels of air pollution are at increased risk for bronchiolitis, according to a new study.
Ford to put air bags into back seat belts of SUV (w/ Video)
Nov 05, 2009 |
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(AP) -- Air bags have long been mounted in the steering wheel, dashboard and sides of vehicles. Now, they're in the seat belts. Ford Motor Co. plans to introduce seat belt-mounted air bags in the back seat ...
Nocturnal wind maximum mapped for first time
Space & Earth / Earth Sciences
Nov 05, 2009 |
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On beautiful, sunny days with quiet weather conditions a strong wind develops in the evening at a height of about 200 metres.
Study finds big air pollution impacts on local communities
Nov 04, 2009 |
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Heavy traffic corridors in the cities of Long Beach and Riverside are responsible for a significant proportion of preventable childhood asthma, and the true impact of air pollution and ship emissions on the disease has likely ...
Common plants can eliminate indoor air pollutants
Nov 04, 2009 |
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Air quality in homes, offices, and other indoor spaces is becoming a major health concern, particularly in developed countries where people often spend more than 90% of their time indoors. Surprisingly, indoor ...
Tiny Music Player Made from Wire Bridge (w/ Video)
Nov 04, 2009 |
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(PhysOrg.com) -- In 2008, scientists built a loudspeaker made of carbon nanotubes that produced sound and music based on the thermoacoustic effect. Now, a different team of scientists has built a loudspeaker ...
Car That Runs on Compressed Air Questioned by Critics (w/ Video)
Nov 03, 2009 |
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(PhysOrg.com) -- As electric cars begin breaking into the short-distance vehicle market, one French company thinks that it has an alternative to the electric vehicle: a car that runs on compressed air. Motor ...
Lawmakers seek ban on laptops in airliner cockpits
Nov 03, 2009 |
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(AP) -- Lawmakers are moving to ban the use of computer laptops and other personal electronic devices in airline cockpits to prevent another incident like the Northwest Airlines plane that overshot Minneapolis by 150 miles.
