https://w3id.org/np/RAYnPNgwGmvUoKDk8g_PTczWcWd_zniIRJbQ0UxjrKOlM/Head https://w3id.org/np/RAYnPNgwGmvUoKDk8g_PTczWcWd_zniIRJbQ0UxjrKOlM http://www.nanopub.org/nschema#hasAssertion https://w3id.org/np/RAYnPNgwGmvUoKDk8g_PTczWcWd_zniIRJbQ0UxjrKOlM/assertion https://w3id.org/np/RAYnPNgwGmvUoKDk8g_PTczWcWd_zniIRJbQ0UxjrKOlM http://www.nanopub.org/nschema#hasProvenance https://w3id.org/np/RAYnPNgwGmvUoKDk8g_PTczWcWd_zniIRJbQ0UxjrKOlM/provenance https://w3id.org/np/RAYnPNgwGmvUoKDk8g_PTczWcWd_zniIRJbQ0UxjrKOlM http://www.nanopub.org/nschema#hasPublicationInfo https://w3id.org/np/RAYnPNgwGmvUoKDk8g_PTczWcWd_zniIRJbQ0UxjrKOlM/pubinfo https://w3id.org/np/RAYnPNgwGmvUoKDk8g_PTczWcWd_zniIRJbQ0UxjrKOlM http://www.w3.org/1999/02/22-rdf-syntax-ns#type http://www.nanopub.org/nschema#Nanopublication https://w3id.org/np/RAYnPNgwGmvUoKDk8g_PTczWcWd_zniIRJbQ0UxjrKOlM/assertion https://doi.org/10.5194/egusphere-2026-114 http://purl.org/dc/terms/creator https://orcid.org/0000-0002-4892-454X https://doi.org/10.5194/egusphere-2026-114 http://purl.org/dc/terms/creator https://orcid.org/0000-0002-8415-6808 https://doi.org/10.5194/egusphere-2026-114 http://purl.org/dc/terms/creator https://orcid.org/0000-0003-1346-5352 https://doi.org/10.5194/egusphere-2026-114 http://purl.org/dc/terms/creator https://orcid.org/0009-0004-6009-6304 https://doi.org/10.5194/egusphere-2026-114 http://purl.org/dc/terms/publisher https://ror.org/03xphts16 https://doi.org/10.5194/egusphere-2026-114 http://purl.org/dc/terms/subject http://aims.fao.org/aos/agrovoc/c_24848 https://doi.org/10.5194/egusphere-2026-114 http://www.w3.org/1999/02/22-rdf-syntax-ns#type https://w3id.org/fair/ff/terms/article https://doi.org/10.5194/egusphere-2026-114 http://www.w3.org/1999/02/22-rdf-syntax-ns#type https://w3id.org/fdof/ontology#FAIRDigitalObject https://doi.org/10.5194/egusphere-2026-114 http://www.w3.org/2000/01/rdf-schema#comment We report hourly surface observations of PM2.5, CO, NOx, O3, and 75 speciated VOCs in Missoula, Montana, during a strong smoke event in 2020. This study tests our current understanding of wildfire emissions, chemistry, and health effects as implemented in the GEOS-Chem chemical transport model. Three-or-more-day-old smoke transported from California and the Pacific Northwest increased CO, PM2.5, and total measured VOCs by factors of 2–8, with hourly maxima of 800 ppb, 120 µg m-3, and 85 ppb, respectively. In contrast, NOx levels were not elevated compared to the urban background. O3 showed a non-monotonic response to wildfire smoke: MDA8 O3 increased under light smoke but flattened or declined when PM2.5 exceeded ~30–40 µg m-3, a feature that GEOS-Chem failed to reproduce. A 2020-style wildfire season recurring annually would yield an excess lifetime cancer risk of 100-in-1 million or approximately 7 times the non-smoke baseline. The noncancer hazard index (HI) would reach 3.0, meaning substantially elevated acute risks during high-smoke periods. About 90 % of cancer risks are from PM2.5, whereas non-cancer risks are dominated by formaldehyde, benzene, acrolein, and acetaldehyde. GEOS-Chem captured major smoke intrusions but underestimated CO, PM2.5, and VOCs by 30–90 %. These model biases propagate to health metrics, with GEOS-Chem underestimating smoke-attributable cancer risk by ~40 % and chronic HI by ~10 times. We attribute the model errors to underpredicted fire emissions and unrepresented VOC chemistry, which together led to an overestimation of OH and insufficient secondary production. https://doi.org/10.5194/egusphere-2026-114 http://www.w3.org/2000/01/rdf-schema#label Characterizing emissions, chemistry, and health impacts of aged wildfire smoke in a western US city https://doi.org/10.5194/egusphere-2026-114 https://schema.org/funder https://ror.org/021nxhr62 https://doi.org/10.5194/egusphere-2026-114 https://w3id.org/fdof/ontology#hasMetadata https://w3id.org/np/RAYnPNgwGmvUoKDk8g_PTczWcWd_zniIRJbQ0UxjrKOlM https://doi.org/10.5194/egusphere-2026-114 https://www.w3.org/ns/dcat#contactPoint lixu.jin@umontana.edu https://doi.org/10.5194/egusphere-2026-114 https://www.w3.org/ns/dcat#endDate January 21 2026 https://doi.org/10.5194/egusphere-2026-114 https://www.w3.org/ns/dcat#startDate 2025 https://w3id.org/np/RAYnPNgwGmvUoKDk8g_PTczWcWd_zniIRJbQ0UxjrKOlM/provenance https://w3id.org/np/RAYnPNgwGmvUoKDk8g_PTczWcWd_zniIRJbQ0UxjrKOlM/assertion http://www.w3.org/ns/prov#wasAttributedTo https://orcid.org/0009-0008-8411-2742 https://w3id.org/np/RAYnPNgwGmvUoKDk8g_PTczWcWd_zniIRJbQ0UxjrKOlM/pubinfo https://orcid.org/0009-0008-8411-2742 http://xmlns.com/foaf/0.1/name Emily Regalado https://w3id.org/np/RAYnPNgwGmvUoKDk8g_PTczWcWd_zniIRJbQ0UxjrKOlM http://purl.org/dc/terms/created 2026-05-01T17:51:21.441Z https://w3id.org/np/RAYnPNgwGmvUoKDk8g_PTczWcWd_zniIRJbQ0UxjrKOlM http://purl.org/dc/terms/creator https://orcid.org/0009-0008-8411-2742 https://w3id.org/np/RAYnPNgwGmvUoKDk8g_PTczWcWd_zniIRJbQ0UxjrKOlM http://purl.org/dc/terms/license https://creativecommons.org/licenses/by/4.0/ https://w3id.org/np/RAYnPNgwGmvUoKDk8g_PTczWcWd_zniIRJbQ0UxjrKOlM http://purl.org/nanopub/x/introduces https://doi.org/10.5194/egusphere-2026-114 https://w3id.org/np/RAYnPNgwGmvUoKDk8g_PTczWcWd_zniIRJbQ0UxjrKOlM http://purl.org/nanopub/x/wasCreatedAt https://nanodash.knowledgepixels.com/ https://w3id.org/np/RAYnPNgwGmvUoKDk8g_PTczWcWd_zniIRJbQ0UxjrKOlM https://w3id.org/np/o/ntemplate/wasCreatedFromProvenanceTemplate https://w3id.org/np/RA7lSq6MuK_TIC6JMSHvLtee3lpLoZDOqLJCLXevnrPoU https://w3id.org/np/RAYnPNgwGmvUoKDk8g_PTczWcWd_zniIRJbQ0UxjrKOlM https://w3id.org/np/o/ntemplate/wasCreatedFromPubinfoTemplate https://w3id.org/np/RACJ58Gvyn91LqCKIO9zu1eijDQIeEff28iyDrJgjSJF8 https://w3id.org/np/RAYnPNgwGmvUoKDk8g_PTczWcWd_zniIRJbQ0UxjrKOlM https://w3id.org/np/o/ntemplate/wasCreatedFromPubinfoTemplate https://w3id.org/np/RAukAcWHRDlkqxk7H2XNSegc1WnHI569INvNr-xdptDGI https://w3id.org/np/RAYnPNgwGmvUoKDk8g_PTczWcWd_zniIRJbQ0UxjrKOlM https://w3id.org/np/o/ntemplate/wasCreatedFromTemplate https://w3id.org/np/RArM5GTwgxg9qslGX-XiQ-KTTUwdoM0KB1YqmT4GqTizA https://w3id.org/np/RAYnPNgwGmvUoKDk8g_PTczWcWd_zniIRJbQ0UxjrKOlM/sig http://purl.org/nanopub/x/hasAlgorithm RSA https://w3id.org/np/RAYnPNgwGmvUoKDk8g_PTczWcWd_zniIRJbQ0UxjrKOlM/sig http://purl.org/nanopub/x/hasPublicKey MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAxzr6UBGMW6c8tegz0babaledWUEQ0PLDE4tp7Iinbe2DZtAtY5JUptKYuStWDZx+QER4808P8dejNWRnBDzgthYJm/AyNSXflHSJhz2+NC+h7RylOLxbwLEQocmyKKiYxa2gT85m6ajVL2M6TnfG67nnK+K2f7iCGL6wYXRITD1q+7+5SWqBdDXIV921W4IKWaD2GJk+NRBoOqQhbsrk8Tn5XsNd7DMYVHk47oMDGbeBnrOIoRPsbBgAcoCsxxhiB9yN6Lf8EUbnlXVEDzJuZk048L1BDZL+6nkA8btTQGP2ijUFWA7rTrod3LjUDQWLZS95njjl867dtmv/znYkzwIDAQAB https://w3id.org/np/RAYnPNgwGmvUoKDk8g_PTczWcWd_zniIRJbQ0UxjrKOlM/sig http://purl.org/nanopub/x/hasSignature IMFhKVm+GQkpWrA7cnpcSc0sOaE/oZ7bGiSLlhpgiWkaVGUseL0EBSep2r74/WzTSFjOISJC0REuavoyJl4GSDOt7KxySL7y0iO3i4QJsaS+xxnEjV3CgmdupkiyIASoWOcTkEe0wGftLm6IqZgCbH/GPwlfdUBuI5GMC+cIs3R9/adH6PO+Nk6GZosyBktvqWwId03WcpzDQhmJifcYKfoeadVYLmbwvyiMnIvABt7BnTqYJa9XEGPONA/cgz4CNsHWZsPPg3caBTo8aOQVk27JSkzBBMkPlbe5TxnpLAWHsgirBXu0RSVFMCFbzj24YqayhDm2ICYo/oQ3NrRyHw== https://w3id.org/np/RAYnPNgwGmvUoKDk8g_PTczWcWd_zniIRJbQ0UxjrKOlM/sig http://purl.org/nanopub/x/hasSignatureTarget https://w3id.org/np/RAYnPNgwGmvUoKDk8g_PTczWcWd_zniIRJbQ0UxjrKOlM https://w3id.org/np/RAYnPNgwGmvUoKDk8g_PTczWcWd_zniIRJbQ0UxjrKOlM/sig http://purl.org/nanopub/x/signedBy https://orcid.org/0009-0008-8411-2742