{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,29]],"date-time":"2026-09-29T14:08:35Z","timestamp":1790690915032,"version":"4.1.0"},"reference-count":63,"publisher":"American Chemical Society (ACS)","issue":"38","license":[{"start":{"date-parts":[[2026,9,18]],"date-time":"2026-09-18T00:00:00Z","timestamp":1789689600000},"content-version":"stm-asf","delay-in-days":0,"URL":"https:\/\/doi.org\/10.15223\/policy-029"},{"start":{"date-parts":[[2026,9,18]],"date-time":"2026-09-18T00:00:00Z","timestamp":1789689600000},"content-version":"stm-asf","delay-in-days":0,"URL":"https:\/\/doi.org\/10.15223\/policy-037"},{"start":{"date-parts":[[2026,9,18]],"date-time":"2026-09-18T00:00:00Z","timestamp":1789689600000},"content-version":"stm-asf","delay-in-days":0,"URL":"https:\/\/doi.org\/10.15223\/policy-045"}],"funder":[{"DOI":"10.13039\/501100021171","name":"Basic and Applied Basic Research Foundation of Guangdong Province","doi-asserted-by":"publisher","award":["2023B0303000007"],"award-info":[{"award-number":["2023B0303000007"]}],"id":[{"id":"10.13039\/501100021171","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100021171","name":"Basic and Applied Basic Research Foundation of Guangdong Province","doi-asserted-by":"publisher","award":["2024A1515011181"],"award-info":[{"award-number":["2024A1515011181"]}],"id":[{"id":"10.13039\/501100021171","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["42321003"],"award-info":[{"award-number":["42321003"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Guangdong Province","award":["2025D03J0010"],"award-info":[{"award-number":["2025D03J0010"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2026,9,29]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>Isoprene-derived secondary organic aerosol (iSOA) forms through complex, nitrogen oxide (NOx) dependent oxidation pathways. Low-NOx conditions favor the IEPOX pathway, yielding 2-methyltetrols (MTLs), whereas high-NOx environments promote the HMML pathway, producing 2-methylglyceric acid (2MGA). Additionally, isoprene-derived highly oxygenated molecules (iHOMs), formed via autoxidation mechanisms involving rapid H-shift reactions of peroxy radicals and analogous H-shifts of alkoxy radicals under atmospherically relevant conditions, may also contribute to iSOA formation. However, their ambient abundance and atmospheric significance remain poorly constrained. Through year-long, regional measurements of PM2.5 across nine sites in the Pearl River Delta (PRD), we quantified six iHOM species. The measured iHOMs had an annual mean concentration of 2.69 \u00b1 3.52 ng m\u20133, with higher concentrations in summer and autumn, and were dominated by methyltartaric acids (MTA, 71%). The relative proportions of particle-phase iSOA tracers for the HOM (MTA), HMML (2MGA), and IEPOX (MTLs) pathways were 10%, 11%, and 79%, respectively. Box model simulations showed that their corresponding gas-phase intermediates, the peroxide isomer set (PIS), HMML, and IEPOX, accounted for 25%, 22%, and 53%, respectively. Together, the ambient observations and model results indicate that the IEPOX pathway makes the largest contribution to iSOA formation in the polluted PRD, whereas the MTA-related HOM pathway and HMML pathway make smaller but non-negligible contributions, particularly in winter. Moreover, pathway partitioning is associated with the isomeric distribution of isoprene hydroxy peroxy radicals (ISOPO2): the HOM pathway originates from limited \u03b4-ISOPO2 (6.5 \u00b1 3.0%), whereas IEPOX and HMML pathways arise from \u03b2-ISOPO2 (93.5 \u00b1 3.0%), with HMML formation further modulated by competition between the MPAN + OH reaction and the temperature-dependent MPAN decomposition.<\/jats:p>","DOI":"10.1021\/acs.est.6c06525","type":"journal-article","created":{"date-parts":[[2026,9,18]],"date-time":"2026-09-18T22:01:23Z","timestamp":1789768883000},"page":"27359-27369","source":"Crossref","is-referenced-by-count":0,"title":["Unveiling\nthe Importance\nof Organic Hydroxy Acids-Related\nAutoxidation Pathway in Isoprene Secondary Organic Aerosol Formation:\nInsights from Aerosol Tracer Composition in the Pearl River Delta"],"prefix":"10.1021","volume":"60","author":[{"given":"Meiyu","family":"Zhao","sequence":"first","affiliation":[{"name":"Guangzhou Institute of Geochemistry, Chinese Academy of Sciences , , ,","place":["Guangzhou, China, 510640"]},{"name":"University of Chinese Academy of Sciences , ,","place":["Beijing, China, 100049"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1218-1879","authenticated-orcid":true,"given":"Xiang","family":"Ding","sequence":"additional","affiliation":[{"name":"Guangzhou Institute of Geochemistry, Chinese Academy of Sciences , , ,","place":["Guangzhou, China, 510640"]},{"name":"Guangzhou Institute of Geochemistry, Chinese Academy of Science , , ,","place":["Guangzhou, China, 510640"]},{"name":"Guangzhou Institute of Geochemistry , , ,","place":["Guangzhou, China, 510640"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3229-8206","authenticated-orcid":true,"given":"Quanfu","family":"He","sequence":"additional","affiliation":[{"name":"The Hong Kong University of Science and Technology (Guangzhou) , , ,","place":["Guangzhou, China, 511453"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Duohong","family":"Chen","sequence":"additional","affiliation":[{"name":"Guangdong Environmental Monitoring Center , , ,","place":["Guangzhou, China, 510308"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tao","family":"Zhang","sequence":"additional","affiliation":[{"name":"Guangdong Environmental Monitoring Center , , ,","place":["Guangzhou, China, 510308"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1982-0928","authenticated-orcid":true,"given":"Xinming","family":"Wang","sequence":"additional","affiliation":[{"name":"Guangzhou Institute of Geochemistry, Chinese Academy of Sciences , , ,","place":["Guangzhou, China, 510640"]},{"name":"Guangzhou Institute of Geochemistry, Chinese Academy of Science , , ,","place":["Guangzhou, China, 510640"]},{"name":"Guangzhou Institute of Geochemistry , , ,","place":["Guangzhou, China, 510640"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"316","published-online":{"date-parts":[[2026,9,18]]},"reference":[{"issue":"14","key":"2026092909080750300_cit1","doi-asserted-by":"publisher","first-page":"5155","DOI":"10.5194\/acp-9-5155-2009","article-title":"The formation, properties and impact of secondary\norganic aerosol: current and emerging issues","volume":"9","author":"Hallquist","year":"2009","journal-title":"Atmos. Chem. Phys."},{"issue":"7521","key":"2026092909080750300_cit2","doi-asserted-by":"publisher","first-page":"218","DOI":"10.1038\/nature13774","article-title":"High secondary\naerosol contribution to particulate\npollution during haze events in China","volume":"514","author":"Huang","year":"2014","journal-title":"Nature"},{"issue":"9","key":"2026092909080750300_cit3","doi-asserted-by":"publisher","first-page":"5119","DOI":"10.5194\/acp-23-5119-2023","article-title":"Insights into characteristics and formation\nmechanisms\nof secondary organic aerosols in the Guangzhou urban area","volume":"23","author":"Zhai","year":"2023","journal-title":"Atmos. Chem. Phys."},{"key":"2026092909080750300_cit4","doi-asserted-by":"publisher","first-page":"1053","DOI":"10.5194\/acp-5-1053-2005","article-title":"Organic\naerosol and global climate modelling:\na review","volume":"5","author":"Kanakidou","year":"2005","journal-title":"Atmos. Chem. Phys."},{"issue":"18","key":"2026092909080750300_cit5","doi-asserted-by":"publisher","DOI":"10.1029\/2022GL100543","article-title":"Secondary Organic Aerosol\nFormation Regulates Cloud\nCondensation Nuclei in the Global Remote Troposphere","volume":"49","author":"Liu","year":"2022","journal-title":"Geophys. Res. Lett"},{"issue":"2","key":"2026092909080750300_cit6","doi-asserted-by":"publisher","first-page":"27003","DOI":"10.1289\/EHP9413","article-title":"Effect of Atmospheric Aging on Soot Particle Toxicity\nin Lung Cell Models at the Air-Liquid Interface: Differential Toxicological\nImpacts of Biogenic and Anthropogenic Secondary Organic Aerosols (SOAs)","volume":"130","author":"Offer","year":"2022","journal-title":"Environ. Health Perspect"},{"issue":"14","key":"2026092909080750300_cit7","doi-asserted-by":"publisher","first-page":"11201","DOI":"10.5194\/acp-21-11201-2021","article-title":"Secondary organic aerosols\nfrom anthropogenic volatile organic compounds contribute substantially\nto air pollution mortality","volume":"21","author":"Nault","year":"2021","journal-title":"Atmos. Chem. Phys."},{"issue":"17","key":"2026092909080750300_cit8","doi-asserted-by":"publisher","first-page":"9317","DOI":"10.5194\/acp-14-9317-2014","article-title":"Global data set of biogenic VOC emissions calculated by the MEGAN\nmodel over the last 30 years","volume":"14","author":"Sindelarova","year":"2014","journal-title":"Atmos. Chem. Phys"},{"issue":"14","key":"2026092909080750300_cit9","doi-asserted-by":"publisher","first-page":"9097","DOI":"10.5194\/acp-19-9097-2019","article-title":"On the sources and sinks\nof atmospheric VOCs: an integrated analysis of recent aircraft campaigns\nover North America","volume":"19","author":"Chen","year":"2019","journal-title":"Atmos. Chem. Phys."},{"issue":"7","key":"2026092909080750300_cit10","doi-asserted-by":"publisher","first-page":"885","DOI":"10.3390\/atmos16070885","article-title":"Research on the\nEmission of Biogenic Volatile Organic Compounds from Terrestrial Vegetation","volume":"16","author":"Pei","year":"2025","journal-title":"Atmosphere"},{"issue":"6","key":"2026092909080750300_cit11","doi-asserted-by":"publisher","first-page":"1471","DOI":"10.5194\/gmd-5-1471-2012","article-title":"The Model\nof Emissions\nof Gases and Aerosols from Nature version 2.1 (MEGAN2.1): an extended\nand updated framework for modeling biogenic emissions","volume":"5","author":"Guenther","year":"2012","journal-title":"Geosci. Model Dev"},{"issue":"14","key":"2026092909080750300_cit12","doi-asserted-by":"publisher","first-page":"4987","DOI":"10.5194\/acp-9-4987-2009","article-title":"A review of Secondary Organic Aerosol\n(SOA) formation from isoprene","volume":"9","author":"Carlton","year":"2009","journal-title":"Atmos. Chem.\nPhys"},{"issue":"5\u20136","key":"2026092909080750300_cit13","doi-asserted-by":"publisher","first-page":"997","DOI":"10.1016\/0960-1686(91)90141-S","article-title":"Aerosol formation\nin the photooxidation of isoprene and \u03b2-pinene","volume":"25","author":"Pandis","year":"1991","journal-title":"Atmos. Environ"},{"issue":"25","key":"2026092909080750300_cit14","doi-asserted-by":"publisher","first-page":"4093","DOI":"10.1016\/j.atmosenv.2004.06.001","article-title":"Formation of secondary\norganic aerosols\nfrom isoprene and its gas-phase oxidation products through reaction\nwith hydrogen peroxide","volume":"38","author":"Claeys","year":"2004","journal-title":"Atmos. Environ"},{"issue":"5661","key":"2026092909080750300_cit15","doi-asserted-by":"publisher","first-page":"1173","DOI":"10.1126\/science.1092805","article-title":"Formation of secondary organic aerosols through photooxidation\nof isoprene","volume":"303","author":"Claeys","year":"2004","journal-title":"Science"},{"issue":"20","key":"2026092909080750300_cit16","doi-asserted-by":"publisher","first-page":"11807","DOI":"10.5194\/acp-15-11807-2015","article-title":"Characterization of a real-time tracer for isoprene\nepoxydiols-derived secondary organic aerosol (IEPOX-SOA) from aerosol\nmass spectrometer measurements","volume":"15","author":"Hu","year":"2015","journal-title":"Atmos. Chem.\nPhys."},{"issue":"15","key":"2026092909080750300_cit17","doi-asserted-by":"publisher","first-page":"6640","DOI":"10.1073\/pnas.0911114107","article-title":"Reactive intermediates\nrevealed in secondary organic\naerosol formation from isoprene","volume":"107","author":"Surratt","year":"2010","journal-title":"Proc. Natl.\nAcad. Sci. U. S. A"},{"issue":"27","key":"2026092909080750300_cit18","doi-asserted-by":"publisher","first-page":"17914","DOI":"10.1039\/C5CP02001H","article-title":"Mechanism of the hydroxyl\nradical oxidation of methacryloyl peroxynitrate (MPAN) and its pathway\ntoward secondary organic aerosol formation in the atmosphere","volume":"17","author":"Nguyen","year":"2015","journal-title":"Phys. Chem. Chem. Phys."},{"issue":"17","key":"2026092909080750300_cit19","doi-asserted-by":"publisher","first-page":"6718","DOI":"10.1073\/pnas.1221150110","article-title":"Epoxide\nas a precursor to secondary organic\naerosol formation from isoprene photooxidation in the presence of\nnitrogen oxides","volume":"110","author":"Lin","year":"2013","journal-title":"Proc. Natl. Acad. Sci. U. S.\nA."},{"issue":"6","key":"2026092909080750300_cit20","doi-asserted-by":"publisher","first-page":"3472","DOI":"10.1021\/acs.chemrev.8b00395","article-title":"Highly Oxygenated Organic Molecules (HOM) from\nGas-Phase Autoxidation Involving Peroxy Radicals: A Key Contributor\nto Atmospheric Aerosol","volume":"119","author":"Bianchi","year":"2019","journal-title":"Chem. Rev."},{"issue":"24","key":"2026092909080750300_cit21","doi-asserted-by":"publisher","first-page":"14516","DOI":"10.1021\/acs.est.9b05075","article-title":"Organic Hydroxy Acids as Highly Oxygenated\nMolecular (HOM) Tracers for Aged Isoprene Aerosol","volume":"53","author":"Jaoui","year":"2019","journal-title":"Environ. Sci. Technol"},{"key":"2026092909080750300_cit22","doi-asserted-by":"publisher","first-page":"145592","DOI":"10.1016\/j.scitotenv.2021.145592","article-title":"Rapid production\nof highly oxidized molecules in isoprene aerosol via peroxy and alkoxy\nradical isomerization pathways in low and high NOx environments: Combined\nlaboratory, computational and field studies","volume":"775","author":"Jaoui","year":"2021","journal-title":"Sci. Total Environ"},{"key":"2026092909080750300_cit23","doi-asserted-by":"publisher","first-page":"2068","DOI":"10.1038\/s41467-025-57336-1","article-title":"Highly oxidized products\nfrom the atmospheric reaction ofhydroxyl radicals with isoprene","volume":"16","author":"Berndt","year":"2025","journal-title":"Nat. Commun"},{"issue":"7","key":"2026092909080750300_cit24","doi-asserted-by":"publisher","first-page":"3337","DOI":"10.1021\/acs.chemrev.7b00439","article-title":"Gas-Phase\nReactions of Isoprene and Its Major\nOxidation Products","volume":"118","author":"Wennberg","year":"2018","journal-title":"Chem. Rev."},{"issue":"12","key":"2026092909080750300_cit25","doi-asserted-by":"publisher","first-page":"9681","DOI":"10.5194\/acp-21-9681-2021","article-title":"Highly oxygenated organic molecule (HOM) formation\nin the isoprene oxidation by NO3 radical","volume":"21","author":"Zhao","year":"2021","journal-title":"Atmos. Chem. Phys."},{"issue":"21","key":"2026092909080750300_cit26","doi-asserted-by":"publisher","first-page":"12255","DOI":"10.1021\/acs.est.8b02783","article-title":"Primary\nFormation of Highly Oxidized Multifunctional Products in the OH-Initiated\nOxidation of Isoprene: A Combined Theoretical and Experimental Study","volume":"52","author":"Wang","year":"2018","journal-title":"Environ. Sci. Technol"},{"issue":"20","key":"2026092909080750300_cit27","doi-asserted-by":"publisher","first-page":"11877","DOI":"10.1002\/2014JD021748","article-title":"Spatial\ndistributions of secondary organic aerosols from isoprene, monoterpenes,\n\u03b2-caryophyllene, and aromatics over China during summer","volume":"119","author":"Ding","year":"2014","journal-title":"J. Geophys. Res.: Atmos"},{"issue":"7","key":"2026092909080750300_cit28","doi-asserted-by":"publisher","first-page":"3149","DOI":"10.1021\/es3037093","article-title":"Impacts\nof Siberian Biomass Burning on Organic Aerosols over the North Pacific\nOcean and the Arctic: Primary and Secondary Organic Tracers","volume":"47","author":"Ding","year":"2013","journal-title":"Environ. Sci. Technol"},{"issue":"13","key":"2026092909080750300_cit29","doi-asserted-by":"publisher","first-page":"6999","DOI":"10.1029\/2017JD028242","article-title":"Secondary\nOrganic Aerosol Formation From Isoprene Epoxides in the Pearl River\nDelta, South China: IEPOX- and HMML-Derived Tracers","volume":"123","author":"He","year":"2018","journal-title":"J. Geophys. Res.: Atmos"},{"issue":"24","key":"2026092909080750300_cit30","doi-asserted-by":"publisher","first-page":"18101","DOI":"10.5194\/acp-18-18101-2018","article-title":"Chemical composition of isoprene\nSOA under acidic and\nnon-acidic conditions: effect of relative humidity","volume":"18","author":"Nestorowicz","year":"2018","journal-title":"Atmos. Chem. Phys"},{"issue":"22","key":"2026092909080750300_cit31","doi-asserted-by":"publisher","first-page":"14403","DOI":"10.5194\/acp-19-14403-2019","article-title":"Impact of anthropogenic\nemissions on biogenic secondary\norganic aerosol: observation in the Pearl River Delta, southern China","volume":"19","author":"Zhang","year":"2019","journal-title":"Atmos. Chem. Phys."},{"key":"2026092909080750300_cit32","doi-asserted-by":"publisher","first-page":"119487","DOI":"10.1016\/j.atmosenv.2022.119487","article-title":"Different roles of primary\nand secondary sources in\nreducing PM2.5: Insights from molecular markers in Pearl\nRiver Delta, South China","volume":"294","author":"Yang","year":"2023","journal-title":"Atmos. Environ"},{"key":"2026092909080750300_cit33","doi-asserted-by":"publisher","first-page":"D05313","DOI":"10.1029\/2011JD016596","article-title":"Tracer-based estimation\nof secondary organic carbon in the Pearl River Delta, south China","volume":"117","author":"Ding","year":"2012","journal-title":"J. Geophys. Res.: Atmos"},{"issue":"8","key":"2026092909080750300_cit34","doi-asserted-by":"publisher","first-page":"4795","DOI":"10.1021\/acs.est.1c06974","article-title":"Observational\nInsights into Isoprene Secondary Organic\nAerosolFormation through the Epoxide Pathway at Three Urban Sites\nfromNorthern to Southern China","volume":"56","author":"Zhang","year":"2022","journal-title":"Environ. Sci.\nTechnol."},{"issue":"10","key":"2026092909080750300_cit35","doi-asserted-by":"publisher","first-page":"1343","DOI":"10.1002\/rcm.1940","article-title":"Characterization of oxygenated derivatives of isoprene\nrelated to 2-methyltetrols in Amazonian aerosols using trimethylsilylation\nand gas chromatography\/ion trap mass spectrometry","volume":"19","author":"Wang","year":"2005","journal-title":"Rapid Commun. Mass Spectrom"},{"issue":"14","key":"2026092909080750300_cit36","doi-asserted-by":"publisher","first-page":"5171","DOI":"10.1021\/es7032636","article-title":"Spatial and seasonal\ntrends in biogenic secondary organic aerosol tracers and water-soluble\norganic carbon in the southeastern United States","volume":"42","author":"Ding","year":"2008","journal-title":"Environ. Sci. Technol"},{"issue":"4","key":"2026092909080750300_cit37","doi-asserted-by":"publisher","first-page":"806","DOI":"10.1021\/acs.jchemed.9b00033","article-title":"KinSim: A Research-Grade,\nUser-Friendly, Visual Kinetics\nSimulator for Chemical-Kinetics and Environmental-Chemistry Teaching","volume":"96","author":"Peng","year":"2019","journal-title":"J. Chem. Educ"},{"issue":"20","key":"2026092909080750300_cit38","doi-asserted-by":"publisher","first-page":"11433","DOI":"10.5194\/acp-15-11433-2015","article-title":"The MCM\nv3.3.1 degradation scheme\nfor isoprene","volume":"15","author":"Jenkin","year":"2015","journal-title":"Atmos. Chem. Phys"},{"issue":"D3","key":"2026092909080750300_cit39","doi-asserted-by":"publisher","first-page":"3565","DOI":"10.1029\/1999JD901070","article-title":"Dependence of the OH concentration on solar UV","volume":"105","author":"Ehhalt","year":"2000","journal-title":"J. Geophys. Res.: atmos"},{"key":"2026092909080750300_cit40","doi-asserted-by":"publisher","first-page":"120227","DOI":"10.1016\/j.atmosenv.2023.120227","article-title":"Local\nradical chemistry driven ozone pollution\nin a megacity: A case study","volume":"318","author":"Guo","year":"2024","journal-title":"Atmos. Environ"},{"issue":"18","key":"2026092909080750300_cit41","doi-asserted-by":"publisher","first-page":"12525","DOI":"10.5194\/acp-22-12525-2022","article-title":"Radical chemistry in\nthe Pearl River Delta: observations\nand modeling of OH and HO2 radicals in Shenzhen in 2018","volume":"22","author":"Yang","year":"2022","journal-title":"Atmos. Chem. Phys."},{"issue":"10","key":"2026092909080750300_cit42","doi-asserted-by":"publisher","DOI":"10.1029\/2021GL093668","article-title":"Comprehensive\nInsights Into O3 Changes During\nhe COVID-19 From O3 Formation Regime and Atmospheric Oxidation\nCapacity","volume":"48","author":"Zhu","year":"2021","journal-title":"Geophys. Res. Lett"},{"issue":"10","key":"2026092909080750300_cit43","doi-asserted-by":"publisher","first-page":"7129","DOI":"10.5194\/acp-19-7129-2019","article-title":"Experimental\nbudgets of OH, HO2, and RO2 radicals and implications\nfor ozone formation in the Pearl\nRiver Delta in China 2014","volume":"19","author":"Tan","year":"2019","journal-title":"Atmos. Chem. Phys."},{"issue":"6","key":"2026092909080750300_cit44","doi-asserted-by":"publisher","first-page":"3493","DOI":"10.5194\/acp-19-3493-2019","article-title":"Daytime atmospheric oxidation capacity in four Chinese\nmegacities during the photochemically polluted season: a case study\nbased on box model simulation","volume":"19","author":"Tan","year":"2019","journal-title":"Atmos. Chem.\nPhys."},{"issue":"3","key":"2026092909080750300_cit45","doi-asserted-by":"publisher","first-page":"1541","DOI":"10.5194\/acp-12-1541-2012","article-title":"Observation and modelling of OH and HO2 concentrations in the Pearl River Delta 2006: a missing OH\nsource in a VOC rich atmosphere","volume":"12","author":"Lu","year":"2012","journal-title":"Atmos. Chem.\nPhys."},{"issue":"5935","key":"2026092909080750300_cit46","doi-asserted-by":"publisher","first-page":"1702","DOI":"10.1126\/science.1164566","article-title":"Amplified Trace Gas\nRemoval in the Troposphere","volume":"324","author":"Hofzumahaus","year":"2009","journal-title":"Science"},{"issue":"22","key":"2026092909080750300_cit47","doi-asserted-by":"publisher","first-page":"11243","DOI":"10.5194\/acp-10-11243-2010","article-title":"Atmospheric OH reactivities in the Pearl River Delta\n- China in summer 2006: measurement and model results","volume":"10","author":"Lou","year":"2010","journal-title":"Atmos. Chem. Phys."},{"issue":"3","key":"2026092909080750300_cit48","doi-asserted-by":"publisher","first-page":"579","DOI":"10.1093\/nsr\/nwy073","article-title":"Exploring atmospheric\nfree-radical chemistry in China: the self-cleansing capacity and the\nformation of secondary air pollution","volume":"6","author":"Lu","year":"2019","journal-title":"Natl.\nSci. Rev"},{"issue":"12","key":"2026092909080750300_cit49","doi-asserted-by":"publisher","first-page":"7057","DOI":"10.5194\/acp-23-7057-2023","article-title":"OH measurements\nin the coastal atmosphere of South China: possible missing OH sinks\nin aged air masses","volume":"23","author":"Zou","year":"2023","journal-title":"Atmos. Chem. Phys"},{"key":"2026092909080750300_cit50","doi-asserted-by":"publisher","first-page":"754","DOI":"10.1016\/j.scitotenv.2013.06.003","article-title":"Uncertainty\nin biogenic isoprene emissions and its\nimpacts on tropospheric chemistry in East Asia","volume":"463","author":"Han","year":"2013","journal-title":"Sci. Total Environ"},{"issue":"2","key":"2026092909080750300_cit51","doi-asserted-by":"publisher","first-page":"143","DOI":"10.1007\/s10874-005-1322-3","article-title":"Urban atmospheric\nchemistry during the PUMA campaign\n1: Comparison of modelled OH and HO2 concentrations with\nmeasurements","volume":"52","author":"Emmerson","year":"2005","journal-title":"J. Atmos. Chem"},{"issue":"16","key":"2026092909080750300_cit52","doi-asserted-by":"publisher","first-page":"1960","DOI":"10.1016\/j.atmosenv.2010.03.001","article-title":"Temporal, spatial\ncharacteristics and uncertainty of biogenic VOC emissions in the Pearl\nRiver Delta region, China","volume":"44","author":"Zheng","year":"2010","journal-title":"Atmos. Environ"},{"issue":"15","key":"2026092909080750300_cit53","doi-asserted-by":"publisher","first-page":"5367","DOI":"10.1021\/jacs.6b12838","article-title":"Isoprene Peroxy Radical Dynamics","volume":"139","author":"Teng","year":"2017","journal-title":"J. Am. Chem. Soc"},{"issue":"14","key":"2026092909080750300_cit54","doi-asserted-by":"publisher","first-page":"6641","DOI":"10.1073\/pnas.1810774116","article-title":"Anthropogenic\nenhancements to production of highly oxygenated molecules from autoxidation","volume":"116","author":"Pye","year":"2019","journal-title":"Proc. Natl. Acad. Sci. U. S. A."},{"issue":"28","key":"2026092909080750300_cit55","doi-asserted-by":"publisher","first-page":"5935","DOI":"10.1039\/b908511d","article-title":"HOx radical\nregeneration in the oxidation\nof isoprene","volume":"11","author":"Peeters","year":"2009","journal-title":"Phys. Chem. Chem. Phys"},{"issue":"38","key":"2026092909080750300_cit56","doi-asserted-by":"publisher","first-page":"8625","DOI":"10.1021\/jp5033146","article-title":"Hydroxyl Radical\nRecycling in Isoprene Oxidation Driven by Hydrogen Bonding and Hydrogen\nTunneling: The Upgraded LIM1Mechanism","volume":"118","author":"Peeters","year":"2014","journal-title":"J. Phys.\nChem. A"},{"issue":"9","key":"2026092909080750300_cit57","doi-asserted-by":"publisher","first-page":"5969","DOI":"10.5194\/acp-16-5969-2016","article-title":"Organic nitrate chemistry and its implications\nfor nitrogen budgets in an isoprene- and monoterpene-rich atmosphere:\nconstraints from aircraft (SEAC4RS) and ground-based (SOAS)\nobservations in the Southeast US","volume":"16","author":"Fisher","year":"2016","journal-title":"Atmos. Chem.\nPhys"},{"issue":"19","key":"2026092909080750300_cit58","doi-asserted-by":"publisher","first-page":"7623","DOI":"10.5194\/acp-9-7623-2009","article-title":"Closing\nthe peroxy acetyl nitrate budget: observations\nof acyl peroxy nitrates (PAN, PPN, and MPAN) during BEARPEX 2007","volume":"9","author":"LaFranchi","year":"2009","journal-title":"Atmos. Chem. Phys."},{"issue":"20","key":"2026092909080750300_cit59","doi-asserted-by":"publisher","first-page":"11403","DOI":"10.1021\/es4011064","article-title":"Observational\nInsights into Aerosol Formation from\nIsoprene","volume":"47","author":"Worton","year":"2013","journal-title":"Environ. Sci. Technol."},{"key":"2026092909080750300_cit60","doi-asserted-by":"publisher","first-page":"3","DOI":"10.1016\/j.atmosenv.2013.03.012","article-title":"Science-policy\ninterplay: Air quality\nmanagement in the Pearl River Delta region and Hong Kong","volume":"76","author":"Zhong","year":"2013","journal-title":"Atmos. Environ"},{"key":"2026092909080750300_cit61","doi-asserted-by":"publisher","first-page":"138711","DOI":"10.1016\/j.energy.2025.138711","article-title":"The impact\nof collaborative governance on air Pollution:\nEvidence from high-frequency data in Pearl river delta, China","volume":"337","author":"He","year":"2025","journal-title":"Energy"},{"issue":"20","key":"2026092909080750300_cit62","doi-asserted-by":"publisher","first-page":"13729","DOI":"10.5194\/acp-25-13729-2025","article-title":"Long-term\nTrends in PM2.5 Chemical Composition\nand Its Impact on Aerosol Properties: Field Observations from 2007\nto 2020 in Pearl River Delta, South China","volume":"25","author":"He","year":"2025","journal-title":"Atmos.\nChem. Phys."},{"key":"2026092909080750300_cit63","doi-asserted-by":"publisher","first-page":"117817","DOI":"10.1016\/j.atmosenv.2020.117817","article-title":"Stabilization for the\nsecondary species contribution\nto PM2.5 in the Pearl River Delta (PRD) over the past decade,\nChina: A meta-analysis","volume":"242","author":"Yan","year":"2020","journal-title":"Atmos. Environ"}],"container-title":["Environmental Science &amp;\nTechnology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/pubs.acs.org\/doi\/pdf\/10.1021\/acs.est.6c06525","content-type":"application\/pdf","content-version":"vor","intended-application":"unspecified"},{"URL":"https:\/\/pubs.acs.org\/esthag\/article-pdf\/60\/38\/27359\/68562504\/acs.est.6c06525.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/pubs.acs.org\/esthag\/article-pdf\/60\/38\/27359\/68562504\/acs.est.6c06525.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,9,29]],"date-time":"2026-09-29T13:41:44Z","timestamp":1790689304000},"score":1,"resource":{"primary":{"URL":"https:\/\/pubs.acs.org\/esthag\/article\/60\/38\/27359\/5433179\/Unveiling-the-Importance-of-Organic-Hydroxy-Acids"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,9,18]]},"references-count":63,"journal-issue":{"issue":"38","published-online":{"date-parts":[[2026,9,18]]},"published-print":{"date-parts":[[2026,9,29]]}},"URL":"https:\/\/doi.org\/10.1021\/acs.est.6c06525","relation":{},"ISSN":["0013-936X","1520-5851"],"issn-type":[{"value":"0013-936X","type":"print"},{"value":"1520-5851","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,9,18]]}}}