Related topics: air pollution · air quality · pollution

Biodiversity loss could be making us sick – here's why

By 2050, 70% of the world's population is expected to live in towns and cities. Urban living brings many benefits, but city dwellers worldwide are seeing a rapid increase in noncommunicable health problems, such as asthma ...

How COVID-19 could impact travel for years to come

In late 2019, the International Air Transport Association (IATA) published its "Economic Performance of the Airline Industry" report. It contained a 2020 forecast of 4.1 percent growth in global air traffic demand and net ...

Six things to know about NASA's Ingenuity Mars helicopter

When NASA's Mars 2020 Perseverance rover launches from Cape Canaveral Air Force Station in Florida later this summer, an innovative experiment will ride along: the Ingenuity Mars Helicopter. Ingenuity may weigh only about ...

Yes, the air was better during lockdown, study shows

If you thought that the air quality improved during the initial COVID-19 lockdown, you were right. A recently published Tufts-led study found a direct connection between the stay-at-home orders following the COVID-19 outbreak ...

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Earth's atmosphere

The 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.

This text uses material from Wikipedia, licensed under CC BY-SA