Accepted for/Published in: JMIR Public Health and Surveillance
Date Submitted: Nov 19, 2025
Open Peer Review Period: Nov 19, 2025 - Jan 14, 2026
Date Accepted: Jun 9, 2026
(closed for review but you can still tweet)
Long-Term Exposure to PM2.5 and Ozone and Acute Respiratory Infections Risk: A Community-Based Prospective Cohort Study
ABSTRACT
Background:
Acute respiratory infections (ARIs) remain a major global health concern, yet evidence on the impact of long-term air pollution exposure on both incident and recurrent ARIs in the general population is still limited.
Objective:
This study aimed to assess the risk of ARIs among residents of a community-based cohort in Shanghai and to investigate the associations between long-term exposure to air pollutants and the risks of both incident and recurrent ARIs.
Methods:
We established a prospective cohort of 3,631 residents in Shanghai, China, who were followed weekly for one year. Individual-level PM2.5, PM10, NO2, and O3 concentrations were estimated using 1 km × 1 km satellite-based models at residential addresses, and exceedance days were calculated. Incident ARIs were analyzed using Cox proportional hazards models, while recurrent ARIs were examined using marginal Cox models with robust standard errors. We further fitted time-varying Cox models to estimate hazard ratio trajectories over the follow-up period. Stratified analyses were conducted to assess potential effect modification by key covariates, and sensitivity analyses were performed using alternative exposure windows, two-pollutant models, and additional models for recurrent ARIs to assess robustness.
Results:
During 3,498 person-years of follow-up, a total of 874 ARIs were recorded (0.25 per person-year). For incident ARIs, each 1 μg/m3 increase in PM2.5, PM10, and O3 was associated with HRs of 1.25 (95% CI: 1.12–1.40), 1.16 (95% CI: 1.03–1.30), and 1.24 (95% CI: 1.18–1.30), respectively. Stronger associations were observed for recurrent ARIs with PM2.5 and PM10, while the effect of O3 remained stable. Time-varying Cox models revealed that the effects of PM2.5 and PM10 gradually attenuated, whereas the effect of O3 appeared later and strengthened over time.
Conclusions:
Long-term exposure to PM2.5, PM10 and O3 significantly increases the risk of both incident and recurrent ARIs, with differential time-varying patterns across pollutants.
Citation
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