Registration Dossier

Environmental fate & pathways

Phototransformation in air

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Description of key information

The atmospheric half life of benzene is calculated to be 5.486 days based on a rate constant of 1.9498 x 10 -12 cm3molecule-1sec-1 and a hydroxyl radical concentration of 1.5E6 OHcm-3 based on the EPISUITE QSAR simulation (US EPA 2012).

Key value for chemical safety assessment

Half-life in air:
13.4 d

Additional information

Information on the atmospheric degradation of benzene was taken from Perry (1977) and the EPISUITE QSAR (US EPA 2012). In Perry 1977, The absolute rate constants for the reaction of OH radicals with a series of aromatic hydrocarbons in the gas phase over the temperature range 296-473 K was determined using flash photolysis-resonance fluorescence technique. Measured data from the author were used to develop rate constants for the reaction of different chemical with hydroxyl radicals. The rate constant has been used to calculate the atmospheric half life of benzene.