atmosfere

Atmosfere is the plural form of atmosfera in Italian and Romanian, meaning "atmosphere" in English. In those languages the term refers to the gaseous envelope surrounding a planet or moon, or to an enclosed air environment such as a room. In English texts, the singular atmosphere is common, with "atmosfere" appearing mainly in translations of those languages or as a proper noun.

An atmosphere is a layer of gases held by gravity around a planetary body. Earth's atmosphere contains roughly 78% nitrogen, 21% oxygen, and small amounts of argon, carbon dioxide, neon, helium, methane, hydrogen, and water vapor. It is structured into layers: troposphere (weather), stratosphere (ozone), mesosphere, thermosphere, and exosphere. The atmosphere regulates surface temperature via the greenhouse effect and mediates weather and climate; it is also the medium of sound and supports life in part by providing oxygen.

For other planets, atmospheres vary widely, with thick CO2 atmospheres on Venus, thin N2/CO2 on Mars, or hydrogen-rich envelopes around gas giants. The study of atmospheres extends to exoplanets, where spectroscopy during transits or direct imaging yields estimates of composition, temperature, pressure, and clouds or hazes; detection of potential biosignature gases is an area of active research.

Within buildings, the term "indoor atmosphere" is used to describe air quality, humidity, and contaminants affecting health and comfort. Monitoring and ventilation are used to manage indoor atmospheres in homes, workplaces, and spacecraft.