Reduced sulfur compounds H2S, DMS, COS

Plants emit DMS and COS (similarly to other organic compounds) predominantly by respiration (Kesselmeier and Hubert 2002). Table 2.68 summarizes global natural sulfur emissions. One of the major estimated sources of COS is the atmos- 

Barkley et al. (2008) found globally tropospheric and stratospheric means to be 433 ppt and 330 ppt, slightly lower than previous measurements of free tropospheric mixing ratio of 480-520 ppt (Notholt et al. 2003) and stratospheric mixing 

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