{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"institution":[{"name":"medRxiv"}],"indexed":{"date-parts":[[2026,10,16]],"date-time":"2026-10-16T04:47:44Z","timestamp":1792126064584,"version":"4.4.0"},"posted":{"date-parts":[[2026,9,29]]},"group-title":"Epidemiology","reference-count":27,"publisher":"openRxiv","license":[{"start":{"date-parts":[[2026,9,29]],"date-time":"2026-09-29T00:00:00Z","timestamp":1790640000000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"award":["R01AG017644"],"award-info":[{"award-number":["R01AG017644"]}],"id":[{"id":"https:\/\/ror.org\/049v75w11","id-type":"ROR","asserted-by":"publisher"}]},{"award":["198-1074"],"award-info":[{"award-number":["198-1074"]}],"id":[{"id":"https:\/\/ror.org\/0187kwz08","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"accepted":{"date-parts":[[2026,10,12]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                <jats:sec>\n                  <jats:title>Importance<\/jats:title>\n                  <jats:p>Long-term exposure to higher average air pollutant concentrations is associated with poorer cognitive health, but annual averages can obscure substantial differences in day-to-day exposure. Whether recurrent high pollution days are associated with long-term cognitive aging trajectories among people with similar overall air pollution exposure is unclear.<\/jats:p>\n                <\/jats:sec>\n                <jats:sec>\n                  <jats:title>Objective<\/jats:title>\n                  <jats:p>\n                    To determine whether the annual number of days exceeding World Health Organization daily guideline values for nitrogen dioxide (NO\n                    <jats:sub>2<\/jats:sub>\n                    ) and particulate matter (PM\n                    <jats:sub>2.5<\/jats:sub>\n                    and PM\n                    <jats:sub>10<\/jats:sub>\n                    ) is associated with subsequent cognitive decline after accounting for annual mean air pollutant exposure.\n                  <\/jats:p>\n                <\/jats:sec>\n                <jats:sec>\n                  <jats:title>Design<\/jats:title>\n                  <jats:p>Prospective cohort study using data from waves 1-10 (2002-03 to 2021-23) of the English Longitudinal Study of Ageing.<\/jats:p>\n                <\/jats:sec>\n                <jats:sec>\n                  <jats:title>Setting<\/jats:title>\n                  <jats:p>Population-based cohort of community-dwelling adults in England.<\/jats:p>\n                <\/jats:sec>\n                <jats:sec>\n                  <jats:title>Participants<\/jats:title>\n                  <jats:p>12,235 adults aged 50+ years at analytic baseline.<\/jats:p>\n                <\/jats:sec>\n                <jats:sec>\n                  <jats:title>Exposures<\/jats:title>\n                  <jats:p>\n                    Number of days exceeding World Health Organization daily guideline values (\u2018exceedance days\u2019) for NO\n                    <jats:sub>2<\/jats:sub>\n                    , PM\n                    <jats:sub>2.5<\/jats:sub>\n                    , and PM\n                    <jats:sub>10<\/jats:sub>\n                    , derived from residence-linked environmental estimates during the calendar year preceding the analytic baseline.\n                  <\/jats:p>\n                <\/jats:sec>\n                <jats:sec>\n                  <jats:title>Main Outcomes and Measures<\/jats:title>\n                  <jats:p>Baseline cognitive performance and model-estimated 14-year cognitive decline (corresponding to the 75th percentile of follow-up duration) in episodic memory and verbal fluency.<\/jats:p>\n                <\/jats:sec>\n                <jats:sec>\n                  <jats:title>Results<\/jats:title>\n                  <jats:p>\n                    Exceedance days were not associated with baseline memory or verbal fluency after adjustment for annual mean air pollutant exposure. More NO\n                    <jats:sub>2<\/jats:sub>\n                    exceedance days were associated with faster cognitive decline: comparing the 75th percentile with the median of NO\n                    <jats:sub>2<\/jats:sub>\n                    exceedance days, the difference in 14-year decline was -0.09 SD (95% CI, -0.17 to -0.01; p = 0.02) for memory and -0.10 SD (95% CI, -0.19 to 0.00; p = 0.04) for fluency. PM\n                    <jats:sub>2.5<\/jats:sub>\n                    and PM\n                    <jats:sub>10<\/jats:sub>\n                    exceedance days were not associated with cognitive decline.\n                  <\/jats:p>\n                <\/jats:sec>\n                <jats:sec>\n                  <jats:title>Conclusions and Relevance<\/jats:title>\n                  <jats:p>\n                    In this cohort study of older adults, a higher number of NO\n                    <jats:sub>2<\/jats:sub>\n                    exceedance days was associated with faster subsequent cognitive decline after adjustment for annual mean air pollutant exposure. This suggests that daily exposure to high NO\n                    <jats:sub>2<\/jats:sub>\n                    concentrations may be related to accelerated cognitive aging even when offset by lower exposure on other days, potentially providing a new rationale for identifying and prioritizing areas with recurrent high NO\n                    <jats:sub>2<\/jats:sub>\n                    exposure and the local emission sources contributing to it.\n                  <\/jats:p>\n                <\/jats:sec>\n                <jats:sec>\n                  <jats:title>Key points<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Question<\/jats:title>\n                    <jats:p>Among individuals with similar average air pollution exposure but different day-to-day exposure patterns, are more high pollution days associated with faster cognitive decline?<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Findings<\/jats:title>\n                    <jats:p>\n                      In this UK-based cohort of 12,235 adults aged 50+, individuals exposed to more days on which nitrogen dioxide (NO\n                      <jats:sub>2<\/jats:sub>\n                      ) concentrations exceeded World Health Organization guideline values subsequently had significantly faster cognitive decline over up to 18 years, after adjustment for annual mean air pollutant exposure. No associations were observed for particulate matter.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Meaning<\/jats:title>\n                    <jats:p>\n                      Daily exposure to high NO\n                      <jats:sub>2<\/jats:sub>\n                      concentrations is associated with faster cognitive decline even when offset by lower concentrations on other days.\n                    <\/jats:p>\n                  <\/jats:sec>\n                <\/jats:sec>","DOI":"10.64898\/2026.09.23.26363787","type":"posted-content","created":{"date-parts":[[2026,9,30]],"date-time":"2026-09-30T00:30:22Z","timestamp":1790728222000},"source":"Crossref","is-referenced-by-count":0,"title":["Daily Exceedance of World Health Organization Air Pollutant Guidelines and Cognitive Aging"],"prefix":"10.64898","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2453-6283","authenticated-orcid":false,"given":"Mikaela","family":"Bloomberg","sequence":"first","affiliation":[{"name":"Department of Epidemiology and Public Health, University College London, London, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6154-1845","authenticated-orcid":false,"given":"Giorgio","family":"Di Gessa","sequence":"additional","affiliation":[{"name":"Department of Epidemiology and Public Health, University College London, London, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7865-5264","authenticated-orcid":false,"given":"Shaun","family":"Scholes","sequence":"additional","affiliation":[{"name":"Department of Epidemiology and Public Health, University College London, London, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2271-3568","authenticated-orcid":false,"given":"Antonio","family":"Gasparrini","sequence":"additional","affiliation":[{"name":"Environment & Health Modelling (EHM) Lab, Department of Public Health, Environments and Society, London School of Hygiene & Tropical Medicine, London UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0001-1543-7999","authenticated-orcid":false,"given":"Arturo","family":"de la Cruz Libardi","sequence":"additional","affiliation":[{"name":"Environment & Health Modelling (EHM) Lab, Department of Public Health, Environments and Society, London School of Hygiene & Tropical Medicine, London UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7808-4943","authenticated-orcid":false,"given":"Andrew","family":"Steptoe","sequence":"additional","affiliation":[{"name":"Department of Behavioural Science and Health, University College London, London, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3036-0499","authenticated-orcid":false,"given":"Paola","family":"Zaninotto","sequence":"additional","affiliation":[{"name":"Department of Epidemiology and Public Health, University College London, London, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"54368","reference":[{"key":"2026101521250748000_2026.09.23.26363787v2.1","doi-asserted-by":"publisher","DOI":"10.1016\/S0140-6736(24)00757-8"},{"key":"2026101521250748000_2026.09.23.26363787v2.2","doi-asserted-by":"publisher","DOI":"10.1016\/S0140-6736(25)01329-7"},{"key":"2026101521250748000_2026.09.23.26363787v2.3","doi-asserted-by":"publisher","DOI":"10.1016\/S0140-6736(24)01296-0"},{"key":"2026101521250748000_2026.09.23.26363787v2.4","doi-asserted-by":"publisher","DOI":"10.3389\/fenvh.2023.1205443"},{"key":"2026101521250748000_2026.09.23.26363787v2.5","doi-asserted-by":"publisher","DOI":"10.1038\/s41467-025-56508-3"},{"key":"2026101521250748000_2026.09.23.26363787v2.6","doi-asserted-by":"publisher","DOI":"10.1289\/ehp10498"},{"key":"2026101521250748000_2026.09.23.26363787v2.7","doi-asserted-by":"publisher","DOI":"10.1038\/s41598-019-44561-0"},{"key":"2026101521250748000_2026.09.23.26363787v2.8","unstructured":"Banks J , Batty GD , Breedvelt J , et al. 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