Registration Dossier
Registration Dossier
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EC number: 200-839-4 | CAS number: 75-10-5
Phototransformation in air
Administrative data
Link to relevant study record(s)
Description of key information
Several studies are available. Difluoromethane (CH2F2) reacts in the lower part of the atmosphere (troposphere) with the radical OH. Possible reactions in the stratosphere are with OH, O1D and by photolysis and were estimated to have a negligible contribution to the atmospheric removal of HFC-32 (WMO 1991). The atmospheric lifetime of HFC-32 was determined at 4.9 years (WMO 2002) based on its tropospheric removal. The lifetime related to reaction with OH is calculated using Spivakovsky et al method (Spivakovsky et al, 2000) which uses methylchloroform as a standard. This approach is considered to give the best average lifetime for long lived species. The corresponding ½ life is by definition ln2x4.9 or 3.39 years. This value is used in the chemical safety assessment.
Key value for chemical safety assessment
- Half-life in air:
- 1 237 d
Additional information
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