3 February 2005
Methyl chloroform in the balance
Use of the solvent methyl chloroform is being phased out under the Montreal Protocol because of its ozone-depleting properties. Its atmospheric concentrations are declining, but recent studies have come to conflicting conclusions about trends in European emissions. Estimates range from less than 100,000 kg per year to over 20 million kg per year, the latter more than doubling previous global estimates. A new study evaluates these estimates based on data from Mace Head in Ireland and Jungfraujoch, Switzerland. The results do not support the recent unexpectedly high estimates, but with emission estimates from 60 million kg per year in the mid-1990s to up to 3.4 million kg per year from 2000 to 2003, they are higher than the latest consumption-based figures. The authors speculate that if these figures are correct, unrecorded methyl chloroform sources must exist, suggesting under-reporting of emissions by industry or of consumption by the Montreal Protocol reporting process.
Low European methyl chloroform emissions inferred from long-term atmospheric measurements
STEFAN REIMANN, ALISTAIR J. MANNING, PETER G. SIMMONDS, DEREK M. CUNNOLD, RAY H. J. WANG, JINLONG LI, ARCHIE MCCULLOCH, RONALD G. PRINN, JIN HUANG, RAY F. WEISS, PAUL J. FRASER, SIMON O'DOHERTY, BRIAN R. GREALLY, KONRAD STEMMLER, MATTHIAS HILL & DORIS FOLINI
Nature 433, 506–508 (2005); doi:10.1038/nature03220
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