Aug 2026· BMJ Open Respiratory Research· Vol 13, pp. e003279· 0 citations· 30 references
Medicine
Abstract
Abstract Objective To investigate associations between short-term fluctuations in urban background air pollution and the incidence of COVID-19 across three Swedish cities using detailed individual-level data. Methods A case-crossover analysis was conducted using individual-level data from a prospective cohort of adults across three Swedish cities (Stockholm, Gothenburg and Uppsala), including 3999 confirmed COVID-19 cases. Subjects were classified as cases on the date of their first positive PCR test, which occurred between 7 March 2020 and 26 January 2022. Exposure data for daily levels of PM2.5, PM10 and NO2 were obtained from urban background monitoring stations. Lag-specific and cumulative associations were examined using distributed lag models and distributed lag non-linear models, adjusting for meteorological variables. Results A significant association was observed between elevated PM2.5 levels and testing positive for COVID-19 on the same day (lag 0), with an OR of 1.084 (95% CI 1.011 to 1.162) per IQR (3.3 µg/m³) increase. Similar lag 0 effects were found across the three cities. For PM10, the most consistent associations were observed at lag 3. For NO2, significant effects at lag 0 emerged only after excluding the final COVID-19 wave. Subgroup analyses showed similar effects among individuals with pre-existing respiratory conditions, though results were less consistent. Conclusions Our findings suggest that short-term fluctuations in air pollution, particularly for PM2.5, are associated with the timing of confirmed COVID-19 cases. A possible explanation for the short lag association is that air pollution exacerbates symptoms, prompting individuals to seek testing, rather than directly facilitating new infections.
Ambient air pollution, particularly fine particulate matter (PM
2.5
), has been linked to cerebrovascular disease. However, findings on the short-term effects of PM
2.5
exposure on hemorrhagic stroke (HS) have been inconsistent across studies. Therefore, this study investigated the association between short-term PM
2.5
exposure and HS hospitalization in Yancheng, China.
An individual-level time-stratified case-crossover study was conducted using hospitalization records of patients with HS from four major hospitals in Yancheng between 2022 and 2024. Conditional logistic regression models were applied to estimate the associations between short-term PM
2.5
exposure and HS hospitalization across different lag structures. Stratified analyses were further performed according to sex, age, hypertension, diabetes, smoking, alcohol consumption, and season.
A total of 2,312 patients hospitalized for HS were included in the analysis. The strongest association was observed at lag01, where each 10 μg/m
3
increase in PM
2.5
concentration was associated with a 3.24% increase in HS hospitalization (95% CI: 0.55%−6.00%). Significant increases were also observed at lag0 and lag1, with corresponding effect estimates of 2.50% (95% CI: 0.11%−4.95%) and 2.76% (95% CI: 0.32%−5.27%), respectively. The associations remained significant after adjustment for ozone (O
3
) but were no longer statistically significant after adjustment for sulfur dioxide (SO
2
), nitrogen dioxide (NO
2
), and carbon monoxide (CO). Relatively stronger effect estimates were observed among females, older adults, individuals with hypertension or diabetes, smokers, alcohol consumers, and during the cold season.
Short-term PM
2.5
exposure was associated with an increased risk of HS hospitalization in Yancheng, China, with the strongest effects observed within the first two days after exposure. The associations were more pronounced among susceptible populations and during the cold season.
K. Qian, Xiao-Rong Xu, Chunxiang Xu et al.· Frontiers in Public Health· 0 citations
A marginally increased risk for PD is observed after higher levels of exposure to O 3 (OR 1.03, 95% CI 1.00-1.06 per IQR) for exposure 6–16 years before the index date, suggesting a possible role of ozone in PD development even at low exposure levels, which requires further studies.
I. Rumrich, A. Korhonen, L. Frohn et al.· npj Parkinson's Disease· 0 citations
Abstract Background Acute respiratory infections (ARIs) remain a major global health concern. Although long-term air pollution exposure has been linked to ARIs, prospective evidence from community-based populations remains limited. Objective This study aimed to quantify the burden of ARIs in the community and examine the associations between long-term exposure to particulate matter 2.5 (PM2.5) and ozone (O3) and the risks of ARIs, with additional analyses using influenza-like illness (ILI) as a more specific outcome. Methods We conducted a prospective cohort study including 3617 residents in Shanghai, China, who were followed weekly for 1 year. Individual-level exposure to PM2.5 and O3 concentrations was estimated using high-resolution datasets. Cox proportional hazards models with shared frailty were applied to assess associations with ARIs. Exposure windows of 3, 6, 9, and 12 months were evaluated, and the optimal window was selected based on the Akaike information criterion. Effect estimates were reported per IQR increase. Dose-response relationships, subgroup analyses, and multiple sensitivity analyses were performed. Results During 3217 person-years of follow-up, 885 ARI events were documented (0.27 per person-year). In the fully adjusted model using the 12-month exposure window, each IQR increase in PM2.5 was associated with higher risks of ARIs (hazard ratio [HR] 1.594, 95% CI 1.340‐1.897), with stronger associations observed for ILI (HR 1.948, 95% CI 1.484‐2.557). For O3, the corresponding HRs were 1.510 (95% CI 1.135‐2.007) for ARIs, with stronger associations for ILI (HR 2.229, 95% CI 1.385‐3.588). PM2.5 showed a nonlinear association with ARIs, whereas linear relationships were observed for PM2.5 with ILI and O3 with both outcomes. Evidence of effect modification was observed by age, residence, and season for PM2.5 and by season for O3. Results were robust across multiple sensitivity analyses. Conclusions Long-term exposure to PM2.5 and O3 is associated with increased risk of ARIs, with similar associations observed for ILI. These findings highlight the importance of long-term air pollution control and targeted interventions for susceptible populations, particularly during cold seasons.
Xiaole Duan, Xiao Yu, Hongyu Liang et al.· JMIR Public Health and Surve...· 0 citations
A significant association between short-term exposure to air pollutants and CKD mortality in the population of Zhejiang Province is revealed and a need for governmental authorities to enhance the monitoring and control of air pollution to mitigate the health burden on the elderly is suggested.
Pin-Yuan Dai, Xiao-Yan Zhou, Wei-Wei Gong et al.· BMC Nephrology· 0 citations
Background Short-term exposure to ambient air pollution has been associated with cardiovascular disease (CVD) mortality, but localized evidence from subtropical cities in southwestern China remains limited. This 11-year time-series study aimed to evaluate the short-term associations between six criteria air pollutants and daily CVD mortality in Nanning, China. Methods We conducted a time-series analysis using daily data on CVD mortality, air pollutant concentrations, and meteorological variables from 2014 to 2024 in Nanning. Generalized additive quasi-Poisson models were used to estimate associations across single-day lags (lag0-lag7) and cumulative lag windows (lag0-1 to lag0-7), adjusting for long-term trends, temperature, relative humidity, and day of the week. Exposure-response relationships were assessed using natural cubic splines. Stratified analyses were conducted by season and age group, and two-pollutant models and sensitivity analyses were performed to evaluate robustness. Results A total of 87,913 CVD deaths were recorded during the study period, of which 57.5% occurred in males and 77.9% occurred among individuals aged ≥65 years. In single-day lag models, PM2.5, PM10, SO2, NO2, and O3-8h showed significant positive associations with CVD mortality at early lag days. At lag0, the RRs were 1.014 (95% CI: 1.008–1.020) for PM2.5, 1.009 (95% CI: 1.006–1.013) for PM10, and 1.018 (95% CI: 1.011–1.026) for NO2, while SO2 showed its largest estimate at lag1 [RR = 1.044 (95% CI: 1.018–1.069)]. In cumulative lag models, PM2.5, PM10, SO2, NO2, and O3-8h showed significant cumulative associations, whereas CO was significant mainly in shorter lag windows. Season-stratified analyses suggested pollutant-specific variation between cold and warm seasons, although formal pollutant-by-season interaction tests were not statistically significant. Age-stratified analyses indicated broader susceptibility among older adults. The main associations were generally robust in sensitivity analyses, distributed lag models, and two-pollutant models, particularly for PM2.5, PM10, and NO2. Conclusion Short-term exposure to ambient air pollution was associated with increased CVD mortality, particularly for PM2.5, PM10, and NO2, with consistent effects across single-day and cumulative lag structures. The results highlight the cardiovascular risks of particulate and traffic-related pollution and support pollutant-specific air quality management and targeted protection for older adults during high-pollution periods.
Xia Luo, Lin-Han Liang, Yang Yu et al.· Frontiers in Public Health· 0 citations
Long-term exposure to ambient fine particulate matter (PM2.5) is the leading environmental risk factor for premature mortality worldwide, yet comprehensive province-level evidence quantifying its health burden across Türkiye remains limited. This study investigated the spatial relationship between long-term PM2.5 exposure and all-cause attributable mortality across all 81 Turkish provinces in 2022 using province-level annual mean PM2.5 concentrations and World Health Organisation (WHO) AirQ+ estimates of PM2.5-attributable deaths among adults aged ≥30 years, assuming a counterfactual concentration of 5 µg/m3. The association between PM2.5 exposure and mortality was evaluated using Pearson and Spearman correlation analyses, ordinary least squares (OLS) regression, a log–log elasticity model, and population-weighted regional and exposure-quartile comparisons, while national temporal indicators for 2010–2023 were reported solely as supplementary context for the primary single-year 2022 cross-sectional analysis. The population-weighted annual mean PM2.5 concentration was 27.0 µg/m3, exceeding the WHO Air Quality Guideline by a factor of 5.4, and all 81 provinces exceeded the recommended threshold. The bivariate OLS model accounted for 41% of the between-province variation in attributable mortality rates (OLS slope = 3.23 additional deaths per 100,000 population for each 1 µg/m3 increase in PM2.5; 95% CI: 2.37–4.10; R2 = 0.41; p < 0.001), while the log–log elasticity model indicated that a 1% increase in PM2.5 concentration was associated with a 0.80% increase in the attributable mortality rate (95% CI: 0.65–0.95). The attributable fraction of natural-cause mortality increased progressively from 8.8% in the lowest exposure quartile to 24.6% in the highest. Nationwide, an estimated 68,440 premature deaths, representing 14.2% of all natural-cause deaths among adults aged ≥30 years, were attributable to PM2.5 exposure. These findings quantify a steep, spatially graded PM2.5-attributable mortality burden across Türkiye. As the attributable estimates derive from the WHO AirQ+ concentration–response function, the gradient describes the magnitude and spatial distribution of the modelled burden rather than an independently estimated exposure–response relationship, and on that basis the results support the adoption of WHO-aligned air-quality standards and accelerated decarbonization strategies to reduce the national health burden attributable to ambient air pollution.
