Daily Exceedance of World Health Organization Air Pollutant Guidelines and Cognitive Aging
- 1University College London
Abstract
ImportanceLong-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.
ObjectiveTo determine whether the annual number of days exceeding World Health Organization daily guideline values for nitrogen dioxide (NO2) and particulate matter (PM2.5 and PM10) is associated with subsequent cognitive decline after accounting for annual mean air pollutant exposure.
DesignProspective cohort study using data from waves 1-10 (2002-03 to 2021-23) of the English Longitudinal Study of Ageing.
SettingPopulation-based cohort of community-dwelling adults in England.
Participants12,235 adults aged 50+ years at analytic baseline.
ExposuresNumber of days exceeding World Health Organization daily guideline values ( exceedance days) for NO2, PM2.5, and PM10, derived from residence-linked environmental estimates during the calendar year preceding the analytic baseline.
Main Outcomes and MeasuresBaseline cognitive performance and model-estimated 14-year cognitive decline (corresponding to the 75th percentile of follow-up duration) in episodic memory and verbal fluency.
ResultsExceedance days were not associated with baseline memory or verbal fluency after adjustment for annual mean air pollutant exposure. More NO2 exceedance days were associated with faster cognitive decline: comparing the 75th percentile with the median of NO2 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. PM2.5 and PM10 exceedance days were not associated with cognitive decline.
Conclusions and RelevanceIn this cohort study of older adults, a higher number of NO2 exceedance days was associated with faster subsequent cognitive decline after adjustment for annual mean air pollutant exposure. This suggests that daily exposure to high NO2 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 NO2 exposure and the local emission sources contributing to it.
Key pointsO_ST_ABSQuestionC_ST_ABSAmong individuals with similar average air pollution exposure but different day-to-day exposure patterns, are more high pollution days associated with faster cognitive decline?
FindingsIn this UK-based cohort of 12,235 adults aged 50+, individuals exposed to more days on which nitrogen dioxide (NO2) 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.
MeaningDaily exposure to high NO2 concentrations is associated with faster cognitive decline even when offset by lower concentrations on other days.
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BibTeX
@misc{bloomberg2026daily,
title = {{Daily Exceedance of World Health Organization Air Pollutant Guidelines and Cognitive Aging}},
author = {M. Bloomberg and G. Di Gessa and S. Scholes and A. Gasparrini and A. de la Cruz Libardi and A. Steptoe and P. Zaninotto},
howpublished = {medRxiv},
year = {2026},
month = sep,
doi = {10.64898/2026.09.23.26363787},
url = {https://www.medrxiv.org/content/10.64898/2026.09.23.26363787v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - Daily Exceedance of World Health Organization Air Pollutant Guidelines and Cognitive Aging
AU - M. Bloomberg
AU - G. Di Gessa
AU - S. Scholes
AU - A. Gasparrini
AU - A. de la Cruz Libardi
AU - A. Steptoe
AU - P. Zaninotto
PY - 2026
DA - 2026/09/23
PB - medRxiv
DO - 10.64898/2026.09.23.26363787
UR - https://www.medrxiv.org/content/10.64898/2026.09.23.26363787v1
AB - ImportanceLong-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. ObjectiveTo determine whether the annual number of days exceeding World Health Organization daily guideline values for nitrogen dioxide (NO2) and particulate matter (PM2.5 and PM10) is associated with subsequent cognitive decline after accounting for annual mean air pollutant exposure. DesignProspective cohort study using data from waves 1-10 (2002-03 to 2021-23) of the English Longitudinal Study of Ageing. SettingPopulation-based cohort of community-dwelling adults in England. Participants12,235 adults aged 50+ years at analytic baseline. ExposuresNumber of days exceeding World Health Organization daily guideline values ( exceedance days) for NO2, PM2.5, and PM10, derived from residence-linked environmental estimates during the calendar year preceding the analytic baseline. Main Outcomes and MeasuresBaseline cognitive performance and model-estimated 14-year cognitive decline (corresponding to the 75th percentile of follow-up duration) in episodic memory and verbal fluency. ResultsExceedance days were not associated with baseline memory or verbal fluency after adjustment for annual mean air pollutant exposure. More NO2 exceedance days were associated with faster cognitive decline: comparing the 75th percentile with the median of NO2 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. PM2.5 and PM10 exceedance days were not associated with cognitive decline. Conclusions and RelevanceIn this cohort study of older adults, a higher number of NO2 exceedance days was associated with faster subsequent cognitive decline after adjustment for annual mean air pollutant exposure. This suggests that daily exposure to high NO2 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 NO2 exposure and the local emission sources contributing to it. Key pointsO_ST_ABSQuestionC_ST_ABSAmong individuals with similar average air pollution exposure but different day-to-day exposure patterns, are more high pollution days associated with faster cognitive decline? FindingsIn this UK-based cohort of 12,235 adults aged 50+, individuals exposed to more days on which nitrogen dioxide (NO2) 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. MeaningDaily exposure to high NO2 concentrations is associated with faster cognitive decline even when offset by lower concentrations on other days.
ER -