Registration Dossier

Environmental fate & pathways

Phototransformation in air

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Administrative data

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Description of key information

The half-lives in air (with OH radicals) ranges from 0.161 days (1,3-butadiene) to 4.064 days (butane)

Key value for chemical safety assessment

Additional information

As the members of this category are gases the most dominant environmental fate process will be photooxidation. Representative substances in this category have been shown to react rapidly with hydroxyl radicals and ozone. The reaction with ozone is less rapid, and therefore less important than the reaction with hydroxyl radicals. However, at night, when the concentration of hydroxyl radicals falls to negligible levels, this removal mechanism will become more important. It is expected that the members of this category will be rapidly removed from the atmosphere by photooxidation.