Dimethyl disulfide (DMDS) and dimethyl sulfide (DMS) emissions from biomass burning in Australia

Simone Meinardi,Nicola J. Blake,F. Sherwood Rowland,Isobel J. Simpson,Donald R. Blake

doi:10.1029/2003gl016967

Simone Meinardi, Nicola J. Blake + Show 3 more

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https://doi.org/10.1029/2003gl016967

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Abstract

We identify dimethyl disulfide (DMDS) as the major reduced sulfur‐containing gas emitted from bushfires in Australia's Northern Territory. Like dimethyl sulfide (DMS), DMDS is oxidized in the atmosphere to sulfur dioxide (SO2) and methane sulfonic acid (MSA), which are intermediates in the formation of sulfuric acid (H2SO4). The mixing ratios of DMDS and DMS were the highest we have ever detected, with maximum values of 113 and 35 ppbv, respectively, whereas background values were below the detection limit (10 pptv). Molar emission ratios relative to carbon monoxide (CO) were [1.6 ± 0.1] × 10−5 and [6.2 ± 0.3] × 10−6, for DMDS and DMS respectively, while molar emission ratios relative to carbon dioxide (CO2) were [4.7 ± 0.4] × 10−6 and [1.4 ± 0.4] × 10−7, respectively. Assuming these observations are representative of biomass burning, we estimate that biomass burning could yield up to 175 Gg/yr of DMDS (119 Gg S/yr) and 13 Gg/yr of DMS.

Highlights

[1] We identify dimethyl disulfide (DMDS) as the major reduced sulfur-containing gas emitted from bushfires in Australia’s Northern Territory
[6] Enhanced DMDS and dimethyl sulfide (DMS) mixing ratios were detected in the biomass burning samples collected during three fire episodes in Northern Australia (Table 1)
Biomass burning in the Australian savanna is estimated to contribute 12– 16% of the carbon released from tropical savanna fires [Hurst et al, 1994]

Summary

Introduction

[2] The emissions of trace gases from biomass burning have been studied extensively during the past two decades because of their potential impact on regional atmospheric chemistry and global climate change [Crutzen et al, 1979; Cofer et al, 1988; Crutzen and Andreae, 1990; Bonsang et al, 1995; Hao et al, 1996; Koppmann et al, 1997]. Among the sulfur-containing gases, emphasis has previously been placed on the biomass burning yields of sulfur dioxide (SO2) and carbonyl sulfide (OCS) [Nguyen et al, 1995]. 2. Experimental [4] For this study, 44 whole air samples were collected at ground level in Northern Australia during the late dry season as part of the BIomass Burning and Lightning Experiment-B (BIBLE-B). [5] The whole air samples were returned to our laboratory at the University of California, Irvine and analyzed for methane (CH4), carbon monoxide (CO), carbon dioxide (CO2), nonmethane hydrocarbons (NMHCs), halocarbons, sulfur gases, and alkyl nitrates. In order to determine the mixing ratios of the sulfur compounds in the biomass burning samples, the mass spectrometer was placed in the single ion monitoring (SIM) mode, choosing the most abundant ion of each compound without interference. For all NMHCs the precision, accuracy and LOD were 1%, 5% and 5 pptv, respectively

Results and Discussion

Compound Katherine Arnhem Land Minimum

Conclusions