title: Low European methyl chloroform emissions inferred from long-term atmospheric measurements.
abstract: Methyl chloroform (CH3CCl3, 1,1,1,-trichloroethane) was used widely as a solvent before it was recognized to be an ozone-depleting substance and its phase-out was introduced under the Montreal Protocol. Subsequently, its atmospheric concentration has declined steadily and recent European methyl chloroform consumption and emissions were estimated to be less than 0.1 gigagrams per year. However, data from a short-term tropospheric measurement campaign (EXPORT) indicated that European methyl chloroform emissions could have been over 20 gigagrams in 2000 (ref. 6), almost doubling previously estimated global emissions. Such enhanced emissions would significantly affect results from the CH3CC13 method of deriving global abundances of hydroxyl radicals (OH) (refs 7-12)-the dominant reactive atmospheric chemical for removing trace gases related to air pollution, ozone depletion and the greenhouse effect. Here we use long-term, high-frequency data from Mace Head, Ireland and Jungfraujoch, Switzerland, to infer European methyl chloroform emissions. We find that European emission estimates declined from about 60 gigagrams per year in the mid-1990s to 0.3-1.4 and 1.9-3.4 gigagrams per year in 2000-03, based on Mace Head and Jungfraujoch data, respectively. Our European methyl chloroform emission estimates are therefore higher than calculated from consumption data, but are considerably lower than those derived from the EXPORT campaign in 2000 (ref. 6).
authors.affiliation: Empa, Institute of Materials Science and Technology, Ueberlandstrasse 129, 8600 Duebendorf, Switzerland. stefan.reimann@empa.ch
authors.forename: Stefan
authors.initials: S
authors.lastname: Reimann
authors.forename: Alistair J
authors.initials: AJ
authors.lastname: Manning
authors.forename: Peter G
authors.initials: PG
authors.lastname: Simmonds
authors.forename: Derek M
authors.initials: DM
authors.lastname: Cunnold
authors.forename: Ray H J
authors.initials: RH
authors.lastname: Wang
authors.forename: Jinlong
authors.initials: J
authors.lastname: Li
authors.forename: Archie
authors.initials: A
authors.lastname: McCulloch
authors.forename: Ronald G
authors.initials: RG
authors.lastname: Prinn
authors.forename: Jin
authors.initials: J
authors.lastname: Huang
authors.forename: Ray F
authors.initials: RF
authors.lastname: Weiss
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Fraser
authors.forename: Simon
authors.initials: S
authors.lastname: O'Doherty
authors.forename: Brian R
authors.initials: BR
authors.lastname: Greally
authors.forename: Konrad
authors.initials: K
authors.lastname: Stemmler
authors.forename: Matthias
authors.initials: M
authors.lastname: Hill
authors.forename: Doris
authors.initials: D
authors.lastname: Folini
mesh_terms: D001272:Atmosphere / Q000737:chemistry*; D004785:Environmental Pollutants / Q000032:analysis*; D005060:Europe; D007391:International Cooperation; D013997:Time Factors; D014240:Trichloroethanes / Q000032:analysis* / Q000737:chemistry
chemical_list: D004785:Environmental Pollutants; D014240:Trichloroethanes; C024566:1,1,1-trichloroethane