{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,31]],"date-time":"2026-10-31T02:26:13Z","timestamp":1793413573355,"version":"4.5.0"},"reference-count":44,"publisher":"American Chemical Society (ACS)","issue":"40","license":[{"start":{"date-parts":[[2026,9,30]],"date-time":"2026-09-30T00:00:00Z","timestamp":1790726400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/"}],"funder":[{"DOI":"10.13039\/100000001","name":"National Science Foundation","doi-asserted-by":"publisher","award":["CHE-2203419"],"award-info":[{"award-number":["CHE-2203419"]}],"id":[{"id":"10.13039\/100000001","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Guangdong provincial project","award":["2023QN10L005"],"award-info":[{"award-number":["2023QN10L005"]}]},{"name":"Guangzhou-HKUST(GZ) Joint Funding Program","award":["2025A03J3948"],"award-info":[{"award-number":["2025A03J3948"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2026,10,13]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>Oxidative stress induced by reactive oxygen species (ROS) is a key process for adverse health effects upon respiratory deposition of particulate matter (PM). Alveolar macrophages can release superoxide upon phagocytosis of PM through a process called the respiratory burst. The release of cellular ROS should depend on both PM composition and dose, but the dose\u2013response relationship for various types of PM remains poorly quantified. Here we measure cellular superoxide production by macrophage cells exposed to secondary organic aerosols (SOA) derived from oxidation of limonene, toluene, and naphthalene, as well as PM generated from biomass burning and flaming combustion of five different types of plastics. We quantify cellular superoxide production over the span of 4 h after an initial exposure of macrophages to PM suspensions by applying a chemiluminescence assay combined with electron paramagnetic resonance. We then define the activation threshold as the dose at which cells exhibit a clear increase in superoxide production. Limonene SOA is found to induce the largest amount of superoxide release (\u223c32 \u03bcM) but has the largest activation threshold of 300 \u03bcg mL\u20131. Naphthalene and toluene SOA show smaller enhancement of superoxide production (\u223c2.5\u20137 \u03bcM) but have lower activation thresholds from 0.02 to 0.1 \u03bcg mL\u20131. Biomass burning PM does not show a clear activation threshold. Plastic burning PM shows a varied response depending on the type of plastic, with PM derived from poly(ethylene terephthalate) (PET) having the highest superoxide production (\u223c12 \u03bcM). The activation thresholds for polystyrene (PS), low-density polyethylene (LDPE), and high-density polyethylene (HDPE) burning PM are very low (\u223c0.01 \u03bcg mL\u20131), while those for poly(vinyl chloride) (PVC) and PET burning PM are substantially higher (50\u2013100 \u03bcg mL\u20131). Our findings highlight the importance of employing dose\u2013response relationships and superoxide activation thresholds, rather than single-dose comparisons, to evaluate and compare the oxidative stress potential of different PMs more accurately.<\/jats:p>","DOI":"10.1021\/acsomega.6c06562","type":"journal-article","created":{"date-parts":[[2026,10,1]],"date-time":"2026-10-01T01:01:35Z","timestamp":1790816495000},"page":"61434-61441","source":"Crossref","is-referenced-by-count":1,"title":["Superoxide Release\nfrom Macrophages upon Exposure\nto Secondary Organic Aerosols, Biomass, and Plastic Burning Particulate\nMatter"],"prefix":"10.1021","volume":"11","author":[{"given":"Kasey C.","family":"Edwards","sequence":"first","affiliation":[{"name":"University of California\u2500Irvine , , , ,","place":["Irvine, California, United States, 92697"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4845-2749","authenticated-orcid":true,"given":"Ting","family":"Fang","sequence":"additional","affiliation":[{"name":"The Hong Kong University of Science and Technology , , , ,","place":["Guangzhou, Guangdong, China, 511400"]},{"name":"The Hong Kong University of Science and Technology , , , ,","place":["Guangzhou, Guangdong, China, 511400"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rizana","family":"Salim","sequence":"additional","affiliation":[{"name":"University of California\u2500Irvine , , , ,","place":["Irvine, California, United States, 92697"]},{"name":"Indian Institute of Technology Madras , , ,","place":["Chennai, India, 600036"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Caitlyn","family":"Cruz","sequence":"additional","affiliation":[{"name":"University of California\u2500Irvine , , , ,","place":["Irvine, California, United States, 92697"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6645-7300","authenticated-orcid":true,"given":"Sukriti","family":"Kapur","sequence":"additional","affiliation":[{"name":"University of California\u2500Irvine , , , ,","place":["Irvine, California, United States, 92697"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7903-7783","authenticated-orcid":true,"given":"Sachin S.","family":"Gunthe","sequence":"additional","affiliation":[{"name":"Indian Institute of Technology Madras , , ,","place":["Chennai, India, 600036"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0891-0052","authenticated-orcid":true,"given":"Sergey A.","family":"Nizkorodov","sequence":"additional","affiliation":[{"name":"University of California\u2500Irvine , , , ,","place":["Irvine, California, United States, 92697"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2532-5373","authenticated-orcid":true,"given":"Manabu","family":"Shiraiwa","sequence":"additional","affiliation":[{"name":"University of California\u2500Irvine , , , ,","place":["Irvine, California, United States, 92697"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"316","published-online":{"date-parts":[[2026,9,30]]},"reference":[{"issue":"38","key":"2026101315081537800_cit1","doi-asserted-by":"publisher","first-page":"9592","DOI":"10.1073\/pnas.1803222115","article-title":"Global estimates of mortality associated with long-term\nexposure to outdoor fine particulate matter","volume":"115","author":"Burnett","year":"2018","journal-title":"Proc. Natl. Acad. Sci. USA"},{"issue":"9","key":"2026101315081537800_cit2","doi-asserted-by":"publisher","first-page":"1689","DOI":"10.1016\/j.freeradbiomed.2008.01.028","article-title":"The role\nof oxidative stress in ambient particulate\nmatter-induced lung diseases and its implications in the toxicity\nof engineered nanoparticles","volume":"44","author":"Li","year":"2008","journal-title":"Free Radic Biol.\nMed."},{"issue":"23","key":"2026101315081537800_cit3","doi-asserted-by":"publisher","first-page":"13545","DOI":"10.1021\/acs.est.7b04417","article-title":"Aerosol Health Effects from Molecular\nto Global Scales","volume":"51","author":"Shiraiwa","year":"2017","journal-title":"Environ. Sci. Technol."},{"issue":"10","key":"2026101315081537800_cit4","doi-asserted-by":"publisher","first-page":"4440","DOI":"10.1021\/cr500487s","article-title":"Multiphase Chemistry at the Atmosphere\u2013Biosphere\nInterface Influencing Climate and Public Health in the Anthropocene","volume":"115","author":"Po\u0308schl","year":"2015","journal-title":"Chem. Rev."},{"issue":"5","key":"2026101315081537800_cit5","doi-asserted-by":"publisher","first-page":"278","DOI":"10.1038\/nchembio.85","article-title":"Reconciling\nthe chemistry and biology of reactive oxygen species","volume":"4","author":"Winterbourn","year":"2008","journal-title":"Nat. Chem. Bio."},{"issue":"1","key":"2026101315081537800_cit6","doi-asserted-by":"publisher","first-page":"260","DOI":"10.1021\/acs.est.0c07789","article-title":"Superoxide Formation\nfrom Aqueous Reactions of Biogenic\nSecondary Organic Aerosols","volume":"55","author":"Wei","year":"2021","journal-title":"Environ. Sci. Technol."},{"issue":"8","key":"2026101315081537800_cit7","doi-asserted-by":"publisher","first-page":"1738","DOI":"10.1021\/acsestair.5c00133","article-title":"Dependence of Reactive Oxygen Species Formation on\nthe Oxidation State of Biogenic Secondary Organic Aerosols","volume":"2","author":"Edwards","year":"2025","journal-title":"ACS ES&T Air"},{"issue":"6","key":"2026101315081537800_cit8","doi-asserted-by":"publisher","first-page":"365","DOI":"10.1080\/152165401753366122","article-title":"Signaling by the respiratory\nburst in macrophages","volume":"51","author":"Forman","year":"2001","journal-title":"Iubmb Life"},{"issue":"4","key":"2026101315081537800_cit9","first-page":"277","article-title":"Alcohol,\noxidative stress, and free radical damage","volume":"27","author":"Wu","year":"2003","journal-title":"Alcohol\nRes. Health"},{"issue":"6","key":"2026101315081537800_cit10","doi-asserted-by":"publisher","first-page":"L1005","DOI":"10.1152\/ajplung.2000.279.6.L1005","article-title":"Reactive oxygen species in cell signaling","volume":"279","author":"Thannickal","year":"2000","journal-title":"Am. J. Physiol-Lung C"},{"issue":"2","key":"2026101315081537800_cit11","doi-asserted-by":"publisher","first-page":"209","DOI":"10.1016\/j.taap.2011.09.007","article-title":"The innate\nand adaptive immune response induced by\nalveolar macrophages exposed to ambient particulate matter","volume":"257","author":"Miyata","year":"2011","journal-title":"Toxicol. Appl. Pharmacol."},{"key":"2026101315081537800_cit12","doi-asserted-by":"publisher","first-page":"1","DOI":"10.3389\/fimmu.2014.00491","article-title":"Macrophage cytokines: involvement\nin immunity and infectious diseases","volume":"5","author":"Arango Duque","year":"2014","journal-title":"Front.\nImmunol."},{"key":"2026101315081537800_cit13","doi-asserted-by":"publisher","first-page":"S340","DOI":"10.1086\/374747","article-title":"Phagocytosis\nand the inflammatory response","volume":"187","author":"Aderem","year":"2003","journal-title":"J. Infect Dis"},{"key":"2026101315081537800_cit14","doi-asserted-by":"publisher","first-page":"88","DOI":"10.1016\/j.imlet.2017.08.016","article-title":"The phagocyte\nrespiratory burst: Historical perspectives and recent advances","volume":"192","author":"Thomas","year":"2017","journal-title":"Immunol. Lett."},{"issue":"23","key":"2026101315081537800_cit15","doi-asserted-by":"publisher","first-page":"17029","DOI":"10.1021\/acs.est.2c03987","article-title":"Superoxide\nRelease by Macrophages through NADPH Oxidase Activation Dominating\nChemistry by Isoprene Secondary Organic Aerosols and Quinones to Cause\nOxidative Damage on Membranes","volume":"56","author":"Fang","year":"2022","journal-title":"Environ. Sci.\nTechnol."},{"issue":"12","key":"2026101315081537800_cit16","doi-asserted-by":"publisher","first-page":"16716","DOI":"10.1096\/fj.202000657R","article-title":"Fine particulate matter inhibits phagocytosis of macrophages by disturbing\nautophagy","volume":"34","author":"Li","year":"2020","journal-title":"Faseb J."},{"issue":"1","key":"2026101315081537800_cit17","doi-asserted-by":"publisher","first-page":"20","DOI":"10.1006\/taap.2000.9096","article-title":"Human alveolar macrophage\nresponses to air pollution\nparticulates are associated with insoluble components of coarse material,\nincluding particulate endotoxin","volume":"171","author":"Soukup","year":"2001","journal-title":"Toxicol. Appl.\nPharmacol."},{"key":"2026101315081537800_cit18","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1155\/2013\/619523","article-title":"Contribution of Lung Macrophages to the Inflammatory\nResponses Induced by Exposure to Air Pollutants","volume":"2013","author":"Hiraiwa","year":"2013","journal-title":"Mediat. Inflamm."},{"issue":"2","key":"2026101315081537800_cit19","doi-asserted-by":"publisher","first-page":"197","DOI":"10.1016\/j.envres.2005.08.007","article-title":"Aggregates of ultrafine particles\nimpair phagocytosis of microorganisms by human alveolar macrophages","volume":"100","author":"Lundborg","year":"2006","journal-title":"Environmental Research"},{"issue":"23","key":"2026101315081537800_cit20","doi-asserted-by":"publisher","first-page":"13949","DOI":"10.1021\/acs.est.9b04449","article-title":"Connecting\nthe Oxidative Potential of Secondary Organic Aerosols with Reactive\nOxygen Species in Exposed Lung Cells","volume":"53","author":"Chowdhury","year":"2019","journal-title":"Environ.\nSci. Technol."},{"issue":"2","key":"2026101315081537800_cit21","doi-asserted-by":"publisher","first-page":"1039","DOI":"10.1021\/acs.est.2c05171","article-title":"Linking Cell Health and Reactive\nOxygen Species from Secondary Organic Aerosols Exposure","volume":"57","author":"Liu","year":"2023","journal-title":"Environ. Sci. Technol."},{"key":"2026101315081537800_cit22","doi-asserted-by":"publisher","first-page":"277","DOI":"10.1146\/annurev-med-052422-020909","article-title":"Health Effects\nof Wildfire Smoke Exposure","volume":"75","author":"Gould","year":"2024","journal-title":"Annu. Rev. Med."},{"issue":"1","key":"2026101315081537800_cit23","doi-asserted-by":"publisher","first-page":"14","DOI":"10.1038\/s44407-025-00015-8","article-title":"Plastic burning particulate\nmatter as a source of environmentally persistent free radicals and\nreactive oxygen and chlorine species","volume":"1","author":"Salim","year":"2025","journal-title":"npj Clean\nAir"},{"key":"2026101315081537800_cit24","doi-asserted-by":"publisher","first-page":"581","DOI":"10.1039\/D2EA00170E","article-title":"Wildfire Particulate\nMatter as a Source of Environmentally Persistent Free Radicals and\nReactive Oxygen Species","volume":"3","author":"Fang","year":"2023","journal-title":"Environ. Sci. Atmos."},{"issue":"15","key":"2026101315081537800_cit25","doi-asserted-by":"publisher","first-page":"6095","DOI":"10.1021\/acs.est.2c08791","article-title":"1,4-Naphthoquinone-Coated\nBlack Carbon, a Kind of Atmospheric Fine Particulate Matter, Affects\nMacrophage Fate: New Insights into Crosstalk between Necroptosis and\nMacrophage Extracellular Traps","volume":"57","author":"Cui","year":"2023","journal-title":"Environ. Sci.\nTechnol."},{"key":"2026101315081537800_cit26","doi-asserted-by":"publisher","first-page":"17029","DOI":"10.1021\/acs.est.2c03987","article-title":"Superoxide\nRelease by Macrophages through NADPH Oxidase Activation Dominating\nChemistry by Isoprene Secondary Organic Aerosols and Quinones to Cause\nOxidative Damage on Membranes","volume":"56","author":"Fang","year":"2022","journal-title":"Environ. Sci.\nTechnol."},{"issue":"4","key":"2026101315081537800_cit27","doi-asserted-by":"publisher","first-page":"1287","DOI":"10.1016\/j.tiv.2013.02.014","article-title":"Respiratory burst in alveolar macrophages exposed to\nurban particles is not a predictor of cytotoxicity","volume":"27","author":"Breznan","year":"2013","journal-title":"Toxicol. in Vitro"},{"issue":"14","key":"2026101315081537800_cit28","doi-asserted-by":"publisher","first-page":"10562","DOI":"10.1021\/acs.est.5c16340","article-title":"Wildland-Urban Interface Fires: Toxic Physicochemical\nProperties of Emitted Particulate Matter and Impacts on Lung Macrophages","volume":"60","author":"DeLoid","year":"2026","journal-title":"Environ. Sci. Technol."},{"issue":"40","key":"2026101315081537800_cit29","doi-asserted-by":"publisher","first-page":"7361","DOI":"10.1021\/acs.jpca.2c05532","article-title":"Effects of Nitrogen\nOxides on the Production of Reactive\nOxygen Species and Environmentally Persistent Free Radicals from \u03b1-Pinene\nand Naphthalene Secondary Organic Aerosols","volume":"126","author":"Edwards","year":"2022","journal-title":"J. Phys. Chem. A"},{"key":"2026101315081537800_cit30","doi-asserted-by":"publisher","first-page":"107366","DOI":"10.1016\/j.envint.2022.107366","article-title":"Exposure to naphthalene and \u03b2-pinene-derived\nsecondary organic aerosol induced divergent changes in transcript\nlevels of BEAS-2B cells","volume":"166","author":"Pardo","year":"2022","journal-title":"Environ. Int."},{"issue":"2","key":"2026101315081537800_cit31","doi-asserted-by":"publisher","first-page":"839","DOI":"10.5194\/acp-17-839-2017","article-title":"Chemical oxidative\npotential of secondary\norganic aerosol (SOA) generated from the photooxidation of biogenic\nand anthropogenic volatile organic compounds","volume":"17","author":"Tuet","year":"2017","journal-title":"Atmospheric Chemistry and Physics"},{"issue":"19","key":"2026101315081537800_cit32","doi-asserted-by":"publisher","first-page":"9731","DOI":"10.5194\/acp-13-9731-2013","article-title":"Naphthalene\nSOA: redox activity and\nnaphthoquinone gas\u2013particle partitioning","volume":"13","author":"McWhinney","year":"2013","journal-title":"Atmospheric Chemistry and Physics"},{"issue":"2","key":"2026101315081537800_cit33","doi-asserted-by":"publisher","first-page":"913","DOI":"10.1021\/jp908530s","article-title":"Chemical Composition\nof Gas- and Aerosol-Phase Products\nfrom the Photooxidation of Naphthalene","volume":"114","author":"Kautzman","year":"2010","journal-title":"J. Phys.\nChem. A"},{"issue":"20","key":"2026101315081537800_cit34","doi-asserted-by":"publisher","first-page":"11642","DOI":"10.1021\/acs.est.8b03695","article-title":"Reactive Oxygen Species Formed by Secondary Organic\nAerosols in Water and Surrogate Lung Fluid","volume":"52","author":"Tong","year":"2018","journal-title":"Environ. Sci. Technol."},{"issue":"41","key":"2026101315081537800_cit35","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.2001378117","article-title":"Proteome-wide\neffects of naphthalene-derived secondary\norganic aerosol in BEAS-2B cells are caused by short-lived unsaturated\ncarbonyls","volume":"117","author":"Han","year":"2020","journal-title":"Proc. Natl. Acad. Sci. U.S.A."},{"issue":"6","key":"2026101315081537800_cit36","doi-asserted-by":"publisher","first-page":"919","DOI":"10.1016\/j.freeradbiomed.2010.05.009","article-title":"Thermodynamic and kinetic considerations for the reaction\nof semiquinone radicals to form superoxide and hydrogen peroxide","volume":"49","author":"Song","year":"2010","journal-title":"Free Radical Biol. Med."},{"issue":"11","key":"2026101315081537800_cit37","doi-asserted-by":"publisher","first-page":"6507","DOI":"10.1021\/acs.est.7b01272","article-title":"Rethinking Dithiothreitol-Based\nParticulate Matter Oxidative Potential: Measuring Dithiothreitol Consumption\nversus Reactive Oxygen Species Generation","volume":"51","author":"Xiong","year":"2017","journal-title":"Environ.\nSci. Technol."},{"key":"2026101315081537800_cit38","doi-asserted-by":"publisher","first-page":"42","DOI":"10.1016\/j.chemosphere.2013.12.079","article-title":"Airborne quinones\ninduce cytotoxicity and DNA damage in human lung epithelial A549 cells:\nThe role of reactive oxygen species","volume":"100","author":"Shang","year":"2014","journal-title":"Chemosphere"},{"issue":"7","key":"2026101315081537800_cit39","doi-asserted-by":"publisher","first-page":"269","DOI":"10.1007\/s10653-025-02578-7","article-title":"PM2.5 from biofuel\nsmoke induces inflammatory response through the\nTRPC6\/Ca2+\/NLRP3 signaling pathway","volume":"47","author":"Chen","year":"2025","journal-title":"Environ.\nGeochem. Health"},{"issue":"25","key":"2026101315081537800_cit40","doi-asserted-by":"publisher","first-page":"5230","DOI":"10.1021\/acs.jpca.0c02094","article-title":"Aqueous-Phase\nDecomposition of Isoprene Hydroxy Hydroperoxide and Hydroxyl Radical\nFormation by Fenton-Like Reactions with Iron Ions","volume":"124","author":"Fang","year":"2020","journal-title":"J. Phys. Chem. A"},{"issue":"8","key":"2026101315081537800_cit41","doi-asserted-by":"publisher","first-page":"839","DOI":"10.1039\/D4EA00049H","article-title":"Modelling molecular\ncomposition of SOA from toluene\nphoto-oxidation at urban and street scales","volume":"4","author":"Sartelet","year":"2024","journal-title":"Environ. Sci. Atmos."},{"issue":"7834","key":"2026101315081537800_cit42","doi-asserted-by":"publisher","first-page":"414","DOI":"10.1038\/s41586-020-2902-8","article-title":"Sources\nof particulate-matter air pollution and its oxidative potential in\nEurope","volume":"587","author":"Daellenbach","year":"2020","journal-title":"Nature"},{"key":"2026101315081537800_cit43","doi-asserted-by":"publisher","first-page":"109","DOI":"10.1038\/s41586-025-09666-9","article-title":"Oxidative potential of atmospheric\nparticles in Europe and exposure scenarios","volume":"647","author":"Tassel","year":"2025","journal-title":"Nature"},{"key":"2026101315081537800_cit44","doi-asserted-by":"publisher","first-page":"7","DOI":"10.1016\/j.freeradbiomed.2020.04.028","article-title":"Ambient\nparticulate matter oxidative potential: Chemical determinants, associated\nhealth effects, and strategies for risk management","volume":"151","author":"Gao","year":"2020","journal-title":"Free Radical Biol. Med."}],"container-title":["ACS Omega"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/pubs.acs.org\/doi\/pdf\/10.1021\/acsomega.6c06562","content-type":"application\/pdf","content-version":"vor","intended-application":"unspecified"},{"URL":"https:\/\/pubs.acs.org\/acsodf\/article-pdf\/11\/40\/61434\/68720573\/acsomega.6c06562.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/pubs.acs.org\/acsodf\/article-pdf\/11\/40\/61434\/68720573\/acsomega.6c06562.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,10,13]],"date-time":"2026-10-13T20:03:27Z","timestamp":1791921807000},"score":1,"resource":{"primary":{"URL":"https:\/\/pubs.acs.org\/acsodf\/article\/11\/40\/61434\/5443042\/Superoxide-Release-from-Macrophages-upon-Exposure"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,9,30]]},"references-count":44,"journal-issue":{"issue":"40","published-online":{"date-parts":[[2026,9,30]]},"published-print":{"date-parts":[[2026,10,13]]}},"URL":"https:\/\/doi.org\/10.1021\/acsomega.6c06562","relation":{},"ISSN":["2470-1343"],"issn-type":[{"value":"2470-1343","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,9,30]]}}}