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Environmental fate & pathways

Phototransformation in air

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Description of key information

In the atmosphere a half-life of 3.6 h for thymol is estimated due to reaction with photochemically produced hydroxyl radicals, considering an OH-concentration of 500,000 radicals/cm³ as a 24-h average (Currenta, 2010).

Key value for chemical safety assessment

Additional information

As no data on phototransfromation in air are available, the rate constant for the atmospheric gas-phase reaction between photochemically produced hydroxyl radicals and organic chemicals is estimated with the Atmospheric Oxidation Program (AOPWIN) of US Environmental Protection Agency. Since the estimated half-life of thymol in air is much shorter than 48 h, no potential of long-range transport of thymol is expected.