Abstract. Emission inventories for major reactive tropospheric CI species (particulate CI, HC1, C1NO2, CH3CI, CHCI3, CH3CCI3, C2C14, C2HC13, CH2C12, and CHCIF2) were integrated across source types (terrestrial biogenic and oceanic emissions, sea-salt production and dechlorination, biomass burning, industrial emissions, fossil-fuel combustion, and incineration). Composite emissions were compared with known sinks to assess budget closure; relative contributions of natural and anthropogenic sources were differentiated. Model calculations suggest that conventional acid-displacement reactions involving Sov)+O3, S(Iv)+ H202, and H2SO4 and HNO3 scavenging account for minor fractions of sea-salt dechlorination globally. Other important chemical pathways involving sea-salt aerosol apparently produce most volatile chlorine in the troposphere. The combined emissions of CH3CI from known sources account for about half of the modeled sink, suggesting fluxes from known sources were unde:estimated, the OH sink was overestimated, or significant unidentified sources exist. Anthropogenic activities (primarily biomass burning) contribute about half the net CH3CI emitted from known sources. Anthropogenic emissions account for only about 10% of the modeled CHCl3 sink. Although poorly constrained, significant fractions of tropospheric CH2C12 (25%), C2HC13 (10%), and C2C14 (5%) are emitted from the surface ocean; the combined contributions of C2C14 and C2HC13 from all natural sources may be substantially higher than the estimated oceanic flux.

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Abstract. Much if not all of the chlorine present in fossil fuels is released into the atmosphere as hydrogen chloride (HC1) and chloromethane (CH3C1, methyl chloride). The chlorine content of oilbased fuels is so low that these sources can be neglected, but coal combustion provides significant releases. On the basis of national statistics for the quantity and quality of coal burned during 1990 in power and heat generation, industrial conversion and residential and commercial heating, coupled with information on the chlorine contents of coals, a global inventory of national HC1 emissions from this source has been constructed. This was combined with an estimate of the national emissions of HC1 from waste combustion (both large-scale incineration and trash burning) which was based on an estimate of the global quantity released from this source expressed per head of population. Account was taken of reduced emissions where flue gases were processed, for example to remove sulphur dioxide. The HC1 emitted in 1990, comprising 4.6 + 4.3 Tg C1 from fossil fuel and 2 + 1.9 Tg C1 from waste btmmtg, was spatially distributed using available information on point sources such as power generation utilities and population density by default. Also associated with these combustion sources are chloromethane emissions, calculated to be 0.075 q-0.07 Tg as C1 (equivalent) from fossil fuels and 0.032 q-0.023 Tg C1 (equivalent) from waste combustion. These were distributed spatially exactly as the HC1 emissions, and a further 0.007 Tg C1 in chloromethane from industrial process activity was distributed by point sources.

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