Carbonyl sulfide concentration atmosphere

Cziczo DJ, Thomson DS, Murphy DM (2001) Ablation, flux, and atmospheric implications of meteors inferred from stratospheric aerosol. Science 291 1772-1775 Dachs J, Eisemeich SJ (2000) Adsorption onto aerosol soot carbon dominates gas-particle partitioning of polycyclic aromatic hydrocarbons. Environ Sci Technol 34 3690-3697 Dalleska NF, Colussi AJ, Hyldahl AM, Hoffmaim MR (2000) Rates and mechanism of carbonyl sulfide oxidation by peroxides in concentrated sulfuric acid. J Phys Chem A 104 10794-10796 D Almeida GA, Schitz L (1983) Number, mass, and volume distributions of mineral aerosol and soils of the Sahara. J Clim Appl Meteorol 22 233-243... 

Unfortunately, very little information is available concerning the concentrations of other reduced sulfur species in the atmosphere. According to Maroulis and Bandy (1977) the DMS level is around 0.005 ppb on the Atlantic Coast, and generally below 0.03 ppb in Virginia (both in U.S.A.). The preliminary results of Sandalls and Penkett (1977) show that in Harwell, England, the mean carbonyl sulfide (COS) level is 0.51 ppb, while the concentration of carbon disulfide (CS2) is found on average to be 0.19 ppb. Much work has to be done, however, before generally accepted values of mean atmospheric levels are obtained. 

Maroulis, P.J., A.L. Torres, and A.R. Bandy, Atmospheric concentrations of carbonyl sulfide in the south-western and eastern United States. Geophys Res Lett 4, 510, 1977. 

Carbonyl sulfide makes up approximately 80% of the total sulfur content of the atmosphere and is the major source of stratospheric aerosols. Carbonyl sulfide is produced within surface waters by photolysis of dissolved organosulfur compounds. Therefore, surface water OCS levels within estuaries exhibit a strong diel trend. Carbonyl sulfide is also added to the water column by diffusion from anoxic sediments, where its production appears to be coupled to microbial sulfate reduction. Diffusion of OCS from the sediment to the water column accounts for 75% of the OCS supplied to the water column and is responsible for the higher OCS concentrations in estuaries relative to the open ocean. While supersaturations of OCS are observed throughout... 

Carbonyl sulfide COS is a sulfur compound present in the troposphere at ca. 0.5 ppbv. It is emitted from volcanic activities and also formed in the atmospheric reaction of CS2 and OH as mentioned above. Among the global emissitm of COS, the ratio of the secondary formation from CS2 is estimated to be ca. 30 % (Chin and Davis 1993). The rate constant of the reaction of COS an OH is very small as seen in Table 5.2 (2 x 10 cm molecule s at 298 K), and the atmospheric lifetime calculated from the average concentration of OH assumed to be 8 x 10 molecules cm is about 20 years. Therefore, most of COS emitted and formed in the troposphere is transported to the stratosphere, where it is photolyzed to yield H2SO4, which causes the stratospheric aerosols (see Chap. 8, Sect. 8.5). 

Carbonyl sulfide, COS, is now recogitized as a eomponent of the atmosphere at a tropospheric concentration of approximately 500 parts per trilhon by volume, corresponding to a global burden of about 2.4 teragrams. It is, therefore, a signifieant sulfiu species in the atmosphere. 

---