Volcanism and emanation

Some recent analyses suggest that up to 40% of the global tropospheric sulfate burden may be volcanic much of it derived from open-vent volcanoes, fumaroles 

Volcanoes regulate the climate through CO2 emissions. Carbon dioxide emissions from volcanoes are given as 75 Tg yr by Textor et al. (2004) and as 200-500 Tg yr by Bickle (1994). The Mt Etna CO2 plume emission and diffuse emission combined to amount to 25 Mt yr (Gerlach 1991). 

The only published estimate attempting to quantify NH3 emissions from a volcano appears to be that of Uematsu et al. (2004) for Mijahama volcano, in the south of Japan. They measured plume concentrations of NH3 up to 5 ppb ( 3 g m ) approximately 100 km downwind of the source, and reported an emission ratio of 1 ammonia 1 ammonium 1 sulfate 10 sulfur dioxide. Based on the estimate that NH , emissions were 15 % of SO2 emissions, they inferred an NH release of 340 kt NH3—N per year for the period since 2000. This is by far the largest NH3 point source emission ever reported, being similar to the total annual NH3 emission of the UK. Improved quantification of global volcanic NH3 and NH4 emissions must therefore be a priority (Sutton et al. 2008). 

Volcanoes emit with the dust many metals Cd, Hg, Ni, Pb, Zn, Ca, Sb, As and Cr (Nriagu and Pacyna 1988) for Cd and Hg metals, volcanoes contribute 40-50 % to global emission and for the latter 20-40 %. Based on global emissions estimates (Nriagu 1989), the emission of heavy metals amounts to 2-50 kt yr b The total volcanic dust emission has been estimated between 25 and 300 Tg yr i (Peterson and Junge 1971, Jonas et al. 1995, Pueschel 1995). 

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