Trace gas
The term Trace gas refers to a gas or gases which make up less than 1% by volume of the earth's atmosphere, and therefore includes all gases except nitrogen (78.1%) and oxygen (20.9%). The most abundant trace gas at 0.934% is argon, which is being continually produced by radioactive decay of 40K in the earth's rocks. Water vapor also occurs in the atmosphere with highly variable abundance.
Several atmospheric trace gases such as ozone O
3, sulfur dioxide SO
2 and nitrogen oxides NO
x are anthropogenic, chemically reactive factors of air quality at a regional level. Others such as carbon dioxide CO
2 and methane CH
4 are important greenhouse gases[1] and are produced anthropogenically but also by plants, microorganisms and from natural geothermal sources.[2][3]
References
- ↑ R.K. Monson & E.A. Holland (2001). "Biospheric trace gas fluxes and their control over tropospheric chemistry". Ann. Rev. Ecol. Sys. 32: 547–576. doi:10.1146/annurev.ecolsys.32.081501.114136.
- ↑ S.J. Hall, P.A. Matson & P.M. Roth (1996). "NOX emissions from soil: Implications for air quality modeling in agricultural regions". Ann. Rev. Energy Env. 21: 311–346.
- ↑ R.K. Monson (2002). "Volatile organic compound emissions from terrestrial ecosystems: A primary biological control over atmospheric chemistry". Israel J. Chem. 42: 29–42. doi:10.1560/0JJC-XQAA-JX0G-FXJG.