Atmospheric oxidation of a thiocarbamate herbicide used in winter cereals.

The gas-phase atmospheric degradation of prosulfocarb (a widely used thiocarbamate herbicide in winter cereals) at different NOx concentrations was investigated at the large outdoor European PHOto-REactor (EUPHORE) in Valencia, Spain. Photolysis under sunlight conditions and reaction with ozone were shown as unimportant. The rate constant for the reaction of prosulfocarb with OH radicals was determined as k = (2.9 +/- 0.5) x 10(-11) cm(3) molecule(-1) s(-1) at 288 +/- 10 K and atmospheric pressure by a conventional relative rate method. Significant ozone and aerosol formation was observed following the reaction of prosulfocarb with OH radicals, and the main detected carbon-containing gas-phase products were benzaldehyde, S-benzyl formyl(propyl)-carbamothioate, and S-benzyl propanoyl(propyl)carbamothioate.