The Geochemistry of the Earth - Thanatia: The Destiny of the Earth's Mineral Resources - page 109

Table 5.2 Gaseous chemical composition of the atmosphere (Prinn, 2004)

Substance Formula Mole frac. in dry air Major sources

Nitrogen N 2 78.084 % Biological

Oxygen O 2 20.948 % Biological

Argon Ar 0.934 % Inert

Carbon dioxide CO 2 360 ppm Combustion, ocean,

biosphere

Neon Ne 18.18 ppm Inert

Helium He 5.24 ppm Inert

Methane CH 4 1.7 ppm Biogenic,

anthropogenic

Hydrogen H 2 0.55 ppm Biogenic,

anthropogenic,
photochemical

Nitrous oxide N 2 O 0.31 ppm Biogenic,

anthropogenic

Carbon
monoxide

CO 50-200 ppb Photochemical,

anthropogenic

Ozone
(troposphere)

O 3 10-500 ppb Photochemical

Ozone
(stratosphere)

O 3 0.5-10 ppm Photochemical

NMHC C x H y 5.0-20 ppb Biogenic,

anthropogenic

Chlorofluorocarbon
12

CF 2 C l2 540 ppt Anthropogenic

Chlorofluorocarbon
11

CFCl 3 265 ppt Anthropogenic

Methylchloroform CH 3 CCl 3 65 ppt Anthropogenic

Carbon
tetrachloride

CCl 4 98 ppt Anthropogenic

Nitrogen oxides NO x 0.01-1 ppm Soils, lightning,

anthropogenic

Ammonia NH 3 0.01-1 ppb Biogenic

Hydroxyl radical OH 0.05 ppt Photochemical

Hydroperoxyl
radical

HO 2 2 ppt Photochemical

Hydrogen
peroxide

H 2 O 2 0.1-10 ppb Photochemical

Formaldehyde CH 2 O 0.1-1 ppb Photochemical

Sulphur dioxide SO 2 0.01-1 ppb Photochemical,

volcanic,
anthropogenic

Dimethyl
sulphide

CH 3 SCH 3 10-100 ppt Biogenic

Carbon
disulfphide

CS 2 1-300 ppt Biogenic,

anthropogenic

Carbonyl
sulphide

OCS 500 ppt Biogenic, volcanic,

anthropogenic

Hydrogen
sulphide

H 2 S 5-500 ppt Biogenic, volcanic