The future of airborne sulfur-containing particles in the absence of fossil fuel sulfur dioxide emissions

Abstract

Sulfuric acid (H 2 SO 4 ), formed from oxidation of sulfur dioxide (SO 2 ) emitted during fossil fuel combustion, is a major precursor of new airborne particles, which have well-documented detrimental effects on health, air quality, and climate. Another precursor is methanesulfonic acid (MSA), produced simultaneously with SO 2 during the atmospheric oxidation of organosulfur compounds (OSCs), such as dimethyl sulfide. In the present work, a multidisciplinary approach is used to examine how contributions of H 2 SO 4 and MSA to particle formation will change in a large coastal urban area as anthropogenic fossil fuel emissions of SO 2 decline. The 3-dimensional University of California Irvine-California Institute of Technology airshed model is used to compare atmospheric concentrations of gas phase MSA, H 2 SO 4 , and SO 2 under current emissions of fossil fuel-associated SO 2 and a best-case futuristic scenario with zero fossil fuel sulfur emissions. Model additions include results from (i) quantum chemical calculations that clarify the previously uncertain gas phase mechanism of formation of MSA and (ii) a combination of published and experimental estimates of OSC emissions, such as those from marine, agricultural, and urban processes, which include pet waste and human breath. Results show that in the zero anthropogenic SO 2 emissions case, particle formation potential from H 2 SO 4 will drop by about two orders of magnitude compared with the current situation. However, particles will continue to be generated from the oxidation of natural and anthropogenic sources of OSCs, with contributions from MSA and H 2 SO 4 of a similar order of magnitude. This could be particularly important in agricultural areas where there are significant sources of OSCs. methanesulfonic acid | sulfuric acid | new particle formation | atmosphere | fossil fuel

Emissions of volatile organic compounds (VOCs) from concentrated animal feeding operations (CAFOs): chemical compositions and separation of sources

“…These VOCs can contribute to the formation of ozone (Howard et al, 2010a, b;Gentner et al, 2014) and fine particles (Sintermann et al, 2014;Perraud et al, 2015), both affecting regional air quality. Many VOCs from CAFOs are also responsible for the unpleasant odor problems nearby or downwind of these facilities (McGinn et al, 2003;Rabaud et al, 2003;Parker et al, 2010;Woodbury et al, 2015).…”

Introductory lecture: atmospheric chemistry in the Anthropocene

“…22, reaction of CH 3 S(O)(O)O with HCHO is predicted to proceed via a submerged transition state in a barrierless reaction. While the radical reaction with CH 4 does have a barrier, other hydrocarbons such as those with weaker 553 However, note that in these studies NO x emissions were kept constant and as seen in Fig. 21, NO x plays a role in forming MSA, something which has been observed in laboratory studies.…”

“…This is again where quantum calculations prove very helpful. 553 As seen in Fig. 22, reaction of CH 3 S(O)(O)O with HCHO is predicted to proceed via a submerged transition state in a barrierless reaction.…”

The changing face of lower tropospheric sulfur oxides in the United States

“…The Perraud et al (2015) study of SCAB air quality provides insight into baseline SO x concentrations occurring in the absence of local SO 2 emissions. The modeling analysis compared results with and without local anthropogenic SO 2 emissions, taking into account oxidized organosulfur compounds from natural sources and from anthropogenic sources such as urban and agricultural activity.…”

“…The relations of emissions to ambient SO x and rainwater SO 4 tend to become more linear after the 1990s, as seen in the observational examples above. Apparent ambiguities in the linearity of the SO 2 and SO 4 responses to emission reductions, however, have implications for the future rate of reduction of SO x and for its chemical interactions in the presence of oxidants and organosulfur compounds (see also Perraud et al, 2015).…”