Cardiology

Five threats to heart health you may not be aware of

Many people can recite the major risk factors for heart disease, the stuff of posters, public service ads and dire warnings: smoking, high blood pressure, obesity, diabetes, high cholesterol, lack of exercise.

Cardiology

Air pollution means pregnant women can't breathe easy

Pregnant women receive a lot of instructions to ensure the healthiest possible baby: what to eat and drink, what to avoid, which vitamins to take, which activities to avoid and more.

Health

Study finds link between hypertension and air pollution

A new study soon to appear in the Journal of Public Health suggests that air pollution and living in apartment buildings may be associated with an increased risk for dangerous conditions like heart disease, stroke, and type ...

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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