Atmospheric chemistry of carbon disulphide

Abstract

The oxidation of carbon disulphide has been studied under conditions which are likely to pertain in the atmosphere. The quantum yield for direct photo-oxidation of CS~ in air at 1 arm pressure, using near UV radiation was 0.012, with OCS as a major product. The rate coefficient (k 1) for the reaction of OH with CS2, was determined from measurements of OCS formation in the near UV photolysis of HONO-CS2-O2-N~ mixtures, kl was dependent on oxygen concentration rising from ~< 4 x 10 -14 cm 3 molecule -1 s -t at O~ ~ 15 Tort to (2.0 +-1.0) x 10 -ta cm s molecule -t s -~ at 1 arm air and 300 K. Equimolar amounts of carbonyl sulphide and sulphur dioxide were the major reaction products.The concentration of carbon disulphide in the ambient atmosphere was measured and the concentration to be expected in the background atmosphere was estimated. Rate and concentration data were used to show that carbon disulphide oxidation represents a major source for atmospheric carbonyl sulphide. It can also serve as an alternate source for atmospheric sulphur dioxide in addition to that produced from hydrogen sulphide and dimethyl sulphide.A consideration of atmospheric concentrations and rate data for these trace sulphur gases suggests that the natural sulphur budget is much smaller than the yearly amounts of sulphur dioxide emitted from anthropogenic sources.

Oxidation of sulphur compounds in the atmosphere: I. Rate constants of OH radical reactions with sulphur dioxide, hydrogen sulphide, aliphatic thiols and thiophenol

“…However, the value determined by Cox and Sheppard (1980) for OH + CHaSH using a relative method in air is approximately a factor of 3 higher than that obtained using an absolute method. A possible explanation of this discrepancy could be that the rate of reaction of OH with CHaSH is dependent upon the partial pressure of 02 present in the system as has recently been demonstrated for OH + CS2 (Jones et al, 1982;Barnes et al, 1983;Jones et al, 1983). However, Wine et al (1984a) conclude from a consideration of their experimental observations and from the product data of Hatakeyama and Akimoto (1983) that an oxygen dependence can not be the reason for the discrepancy in this particular case.…”

Measurements of various sulphur gases in a coastal marine environment

“…Bingemer found concentrations of DMS in the North Sea for April (first annual plankton bloom) were as high as 900 ng (S) 1-1 Air concentrations of CS2 which were determined, showed no seasonal trend and gave a mean value of 980-+ 480 ng (S)m -3. Jones et al (1983) give data for atmospheric CS2 concentrations, measured at Harwell, U.K. Two distinct sample populations were found, one with a modal value close to 80 ng (S) m-3 and the other between 530 and 800 ng (S) m-3. They suggest that the latter may indicate the presence of a strong intermittent source.…”

The long‐wavelength photochemistry of carbon disulfide

“…There is one other paper that investigated the photooxidation of C82 at low PCS2 [Jones et al, 1983]. They found that •OCS =0.012 and did not report a first-order dependence of d>CS2 on PCS 2.…”