Atmospheric Reactivity of Gaseous Dimethyl Sulfate

The atmospheric reactivity of dimethyl sulfate (DMS) with a series of atmospheric species has been investigated. Upper limits to the rate constants for the homogeneous gas-phase reactions of DMS with O₃, NH₃, and H₂O have been determined by using FTIR spectroscopy and are <1.4 × 10⁻²¹, <1.5 × 10⁻²¹, and <1.1 × 10⁻²³ cm³ molecule⁻¹ s⁻¹, respectively. The reactivity of DMS toward OH radicals and Cl atoms has been determined by using relative rate techniques, and the rate constants for those reactions are <5 × 10⁻¹³ and (4.2 ± 0.5) × 10⁻¹³ cm³ molecule⁻¹ s⁻¹, respectively. These rate constants correspond to atmospheric lifetimes ranging from >23 days with respect to reaction with OH radicals to >33 years with respect to reaction with ozone. With the possible exception of its reaction with water, for which the calculated lifetime of DMS is >2 days, these results indicate that the atmospheric fate of DMS is not determined by its homogeneous gas-phase reactions with any of the atmospheric species studied.