biostudies-literatureMoch JMU.S. Environmental Protection AgencyRegione Emilia-RomagnaAlexander S. Onassis Public Benefit FoundationDivision of Atmospheric and Geospace SciencesEuropean Commissione2020JD032706https://www.ebi.ac.uk/biostudies/studies/S-EPMC7685164biostudies-literatureUnknown125(18)Sulfur compounds are an important constituent of particulate matter, with impacts on climate and public health. While most sulfur observed in particulate matter has been assumed to be sulfate, laboratory experiments reveal that hydroxymethanesulfonate (HMS), an adduct formed by aqueous phase chemical reaction of dissolved HCHO and SO₂, may be easily misinterpreted in measurements as sulfate. Here we present observational and modeling evidence for a ubiquitous global presence of HMS. We find that filter samples collected in Shijiazhuang, China, and examined with ion chromatography within 9 days show as much as 7.6 μg m^-3 of HMS, while samples from Singapore examined 9-18 months after collection reveal ~0.6 μg m^-3 of HMS. The Shijiazhuang samples show only miJournal of geophysical research. Atmospheres : JGRGlobal Importance of Hydroxymethanesulfonate in Ambient Particulate Matter: Implications for Air Quality.PMC7685164265148DRG 428/1083587201AGS1644998DGR 1971/2013Dombek TLKuwata MYang LShao JBudisulistiorini SHDovrou EKeutsch FNMickley LJJacob DJMunger JWDecesari SMoch JMLiu ZAlexander BPaglione MWang YfalseGlobal Importance of Hydroxymethanesulfonate in Ambient Particulate Matter: Implications for Air Quality.Sulfur compounds are an important constituent of particulate matter, with impacts on climate and public health. While most sulfur observed in particulate matter has been assumed to be sulfate, laboratory experiments reveal that hydroxymethanesulfonate (HMS), an adduct formed by aqueous phase chemical reaction of dissolved HCHO and SO₂, may be easily misinterpreted in measurements as sulfate. Here we present observational and modeling evidence for a ubiquitous global presence of HMS. We find that filter samples collected in Shijiazhuang, China, and examined with ion chromatography within 9 days show as much as 7.6 μg m^-3 of HMS, while samples from Singapore examined 9-18 months after collection reveal ~0.6 μg m^-3 of HMS. The Shijiazhuang samples show only mi2020-01-01T00:00:00Z2020 Sep2026-07-16T07:09:22.857Z2025-04-05T17:29:03.215ZS-EPMC76851643328261210.1029/2020JD032706