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Environmental fate & pathways

Phototransformation in air

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Description of key information

The tropospheric half-life of p-cresol is approximately 8 h due to degradation by OH radicals with an average concentration of 500000 radicals/mL .
An even shorter half-life of 3.8 h at 23°C is calculated for p-cresol from smoke chamber experiment at different tempertures.

Key value for chemical safety assessment

Half-life in air:
8 h

Additional information

In the atmosphere, p-cresol will react with photochemically produced hydroxyl-radicals. In his critical review Atkinson recommended values for the reaction constant kOH at room temperature of 4.7 x 10-11 cm³ x molecule-per second. Based on a tropospheric OH radical concentration of 5 x 105molecules per cm³ a corresponding half-life of 8.0 h can be calculated.

In an experiment the temperature dependency of the reaction constants in a smog chamber was determined. The calculated half-life is 3.8 h for p-cresol at 23°C.