Atmospheric chemistry

Atmospheric chemistry is a branch of atmospheric science in which the chemistry of the Earth's atmosphere and that of other planets is studied. It is a multidisciplinary field of research and draws on chemistry, physics, meteorology, computer modeling, oceanography, geology and volcanology and other disciplines. Research is increasingly connected with other areas of study such as climatology.

The composition and chemistry of the atmosphere is of importance for several reasons, but primarily because of the interactions between the atmosphere and living organisms. The composition of the Earth's atmosphere has been changed by human activity and some of these changes are harmful to human health, crops and ecosystem. Examples of problems which have been addressed by atmospheric chemistry include acid rain, photochemical smog and global warming. Atmospheric chemistry seeks to understand the causes of these problems and by obtaining a theoretical understanding of them allow possible solutions to be tested and the effects of changes in government policy evaluated.

Atmospheric Composition

Average composition of dry atmosphere, by volume
Gas	per NASA
Nitrogen	78.084%
Oxygen	20.946%
Argon	0.934%
Minor constituents in ppmv.
Carbon Dioxide	350
Neon	18.18
Helium	5.24
Methane	1.7
Krypton	1.14
Hydrogen	0.55
Water vapor	Highly variable; typically makes up about 1%

Notes: the concentration of CO₂ and CH₄ vary by season and location. Ppmv represents parts per million by volume.
The mean molecular mass of air is 28.97 g/mole.

External links

http://www.igac.noaa.gov/ IGAC The International Global Atmospheric Chemistry Project