Emissions of methyl chloroform (CH3CCl3) from biomass burning and the tropospheric methyl chloroform budget

The only known sources of atmospheric methyl chloroform are industrial production and biomass burning. With the phase‐out of industrial methyl chloroform production the atmospheric burden of methyl chloroform is rapidly declining. Consequently the potential importance of nonindustrial sources is increasing. Up to now only one experimental investigation of methyl chloroform emissions from biomass burning has been published. Here laboratory studies of methyl chloroform emission from wood burning are presented. The emission ratios relative to carbon dioxide and carbon monoxide are 12.7 ± 2.6 × 10−8 and 15.6 ± 3.3 × 10−7, respectively. Although based on a limited number of measurements, they strongly suggest that methyl chloroform emissions from biomass burning are at the lower end of previous estimates. The impact of these emissions on the chemistry of the atmosphere will be marginal. However, reliable knowledge of the biomass burning source strength will be essential for a detailed analysis of the trend of atmospheric methyl chloroform concentrations.