Front. Public Health Frontiers in Public Health Front. Public Health 2296-2565 Frontiers Media S.A. 10.3389/fpubh.2026.1742521 Original Research Mortality risk effects of ozone and meteorological factors: a 10-year time-series study Cao Na 1 2 3 † Writing – original draft Visualization Data curation Validation Conceptualization Methodology Writing – review & editing Formal analysis Software Yang Xiaojuan 4 † Writing – review & editing Methodology Data curation Investigation Chen Yifei 1 2 3 † Writing – original draft Formal analysis Writing – review & editing Zhao Lifang 1 2 3 Writing – review & editing Data curation Supervision Funding acquisition Guo Shuai 1 2 3 Data curation Writing – review & editing Funding acquisition Supervision Li Rui 1 2 3 Writing – review & editing Supervision Data curation Zhu Guiming 3 5 Data curation Supervision Writing – review & editing Visualization Ma Lin 4 Methodology Data curation Writing – review & editing Zhang Zhihong 1 2 3 * Resources Project administration Funding acquisition Supervision Methodology Conceptualization Writing – review & editing Department of Environmental Health, School of Public Health, Shanxi Medical University, Taiyuan, China Yellow River Basin Ecological Public Health Security Center, Shanxi Medical University, Taiyuan, China MOE Key Laboratory of Coal Environmental Pathogenicity and Prevention, Shanxi Medical University, Taiyuan, China Shanxi Center for Disease Control and Prevention, Taiyuan, China Department of Health Statistics, School of Public Health, Shanxi Medical University, Taiyuan, China Correspondence: Zhihong Zhang, zzh1973@sxmu.edu.cn

These authors have contributed equally to this work

 18 02 2026 2026 14 1742521 09 11 2025 25 01 2026 31 01 2026 Copyright © 2026 Cao, Yang, Chen, Zhao, Guo, Li, Zhu, Ma and Zhang. 2026 Cao, Yang, Chen, Zhao, Guo, Li, Zhu, Ma and Zhang https://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. Background

Tropospheric ozone (O₃) is increasingly becoming the dominant urban air pollutant in China, posing significant public health risks that are exacerbated by meteorological conditions. A clear understanding of how O₃-related health effects are modified by atmospheric factors is crucial for targeted risk mitigation.

 Methods

This ten-year time-series study (2013–2022) was conducted in Taiyuan, China. We analyzed data on daily O₃ concentrations, meteorological factors, and all-cause and cause-specific mortality. The analysis employed Generalized Additive Models (GAMs) to assess the lagged effects of O₃ exposure on mortality and to investigate the interactions between O₃ and key atmospheric determinants, including temperature, sunshine duration, and season.

 Results

The study revealed distinct patterns of O₃-related mortality risk modified by meteorological conditions. The 10-year average daily O₃ concentration was 92.92 μg/m3. O₃ exposure significantly contributed to all-cause, respiratory, and circulatory mortality with lagged effects. While atmospheric pressure, sunshine duration, temperature, and season all influenced the O₃-mortality relationship, the effect was primarily modified through significant interactions with sunshine duration, season, and temperature. These interactive health risks were more pronounced among females and the older adults.

 Conclusion

Our study provides strong evidence that O3 increases the risk of all-cause, respiratory and circulatory mortality in the population. In addition, there were interactions between meteorological factors and O3, primarily involving sunshine duration, season and temperature.

 generalized additive model health risk assessment interaction meteorological factors mortality ozone The author(s) declared that financial support was received for this work and/or its publication. The work was supported by the National Natural Science Foundation of China (no. 82273595); Shanxi Province Higher Education “Billion Project” Science and Technology Guidance Project (BYBLD005); the Horizontal Project of Shanxi Centre for Disease Control and Prevention (No. 2023049); the Open Fund from China CDC Key Laboratory of Environment and Population Health, National Institute of Environmental Health, Chinese Center for Disease Control and Prevention (no. 2023-CKL-02); the Startup Foundation for Doctors of Shanxi Province (SD2219) and Startup Foundation for Doctors of Shanxi Medical University (XD2123). section-at-acceptance Environmental Health and Exposome Introduction

Air pollution stands as the leading global environmental health risk, accounting for approximately 6.7 million deaths annually and significantly exacerbating public health crises, particularly as anthropogenic ozone (O₃) pollution continues its upward trajectory, further intensifying its role as a critical environmental determinant of the global disease burden (1, 2). In Chinese cities, O3 pollution has become the leading air quality concern in many urban areas (3, 4). Presently, the country faces an unparalleled crisis of O3 pollution, which is even more severe than in other parts of the globe (3). O3 concentrations in China are projected to continue rising through 2050 (5). Therefore, studying the health effects of O3 exposure is essential in public health research.

Ambient O3 pollution continues to pose a significant global environmental health hazard (6). Acute exposure drove a 94% rise in premature deaths in China during 2013–2018, and high-O₃ events boost all-cause mortality (3, 7). Nationwide cohort studies in China have shown that long-term exposure to ozone significantly increases the risk of premature death and reduces life expectancy. It harms the circulatory, cardiovascular, respiratory, and neurological systems, with delayed effects seen in higher non-accidental mortality (2, 6, 7).

Ground O3 levels are influenced by both anthropogenic and meteorological factors, with atmospheric parameters serving as key drivers of surface O3 formation in Chinese urban areas throughout the year. Multivariable regression highlighted varying impacts from hydrometeorological variables [precipitation (PE), thermal radiation (TE), relative humidity (RH), photoperiod duration (SD), barometric pressure (AP), and wind velocity (WS)], particularly thermal radiation and photoperiod duration, which are key catalysts in O3 photochemical processes (8). Another study found that RH, among meteorological factors, is the primary driver of changes in O3 concentration (9). The SD, TE difference between day and night, and extreme high and low TE are all associated with an increased risk of all-cause death among residents (10–12). Additionally, research indicates that both cold and extreme heat influence cardiovascular mortality (13); lower AP values were notably associated with the occurrence of pulmonary embolism (14), while RH and TE were associated with the mortality risk of diabetes mellitus (15). A cohort study found a notable modifying effect of TE on the relationship between mortality and O3 (16, 17). Extreme heat and O3 significantly increase daily hospitalization rates for older patients with coronary heart disease, and their synergistic interaction exhibits a dose–response relationship in exacerbating cardiovascular morbidity (18). Currently, there is no relevant research on the joint effects of other meteorological factors and O3 on the population’s mortality risk. As the capital of Shanxi Province, Taiyuan’s air pollution primarily stems from coal smoke, which may differ from the general patterns. Monthly urban air quality reports from China’s Ministry of Ecology and Environment show a sustained annual increase in O3, the primary monthly pollutant in Taiyuan, between 2015 and 2023. The association between O3 and all-cause mortality risk in the Taiyuan population remains unclear. Additionally, it is uncertain how O3 interacts with meteorological factors to influence the risk of all-cause mortality in this population. Therefore, we have conducted relevant research to provide strong evidence for controlling O3 levels and reducing air pollution in China and globally.

 Materials and methods Data collection

We collected air pollution, meteorological, and cause-of-death monitoring data from January 1, 2013, to December 31, 2022, in Taiyuan City. The air quality measurements consist of the daily average concentrations of PM2.5, PM10, SO2, NO2, and CO over 24 h, as well as the maximum 8-h average concentration of O3 (MDA8 O₃). The climatological records comprise a 24-h mean ambient temperature (°C), humidity (%), wind velocity (m/s), sunshine duration (h), rainfall accumulation (mm), and surface pressure (hPa). Comprehensive mortality figures for all causes among Taiyuan residents were sourced from the National Health Protection Information System of the Chinese Center for Disease Control and Prevention, covering January 1, 2013, to December 31, 2022. Historical meteorological data were obtained from the National Meteorological Science Data Center.1 Daily air pollutant data were sourced from the National Air Quality Real-time Publishing Platform.2 Missing values were addressed using linear interpolation. In this study, the historical observed data had a missing rate of less than 0.1%; therefore, the impact of imputation on the overall results was considered negligible.

According to the International Statistical Classification of Diseases and Related Health Problems 10th Revision (ICD-10), the daily all-cause mortality data were classified as due to tumors (C00-D48), respiratory system diseases (J00-J99), circulatory system diseases (I00-I99), and nervous system diseases (G00-G99) (19). Mortality from all causes, as well as fatalities resulting from tumors, diseases of the respiratory system, circulatory system, and nervous system, were categorized according to gender and age, defining individuals under 65 years as young and those aged 65 years and older as older adults; 24-h daily average atmospheric pressure and temperature were both dichotomized according to the median and were operationally characterized as depressed barometric pressure, elevated low barometric pressure, high barometric pressure, low temperature and high temperature in respective order. The average duration of sunshine in China is 6.39 h, based on which we divided the sunshine duration into short and long sunshine durations (20). The warm season encompasses the months of May through September, while the cold season comprises the remaining months from October to April (21). Days with temperatures at or above the 97.5 percentile are designated as “extreme heat”; all others are categorized as “non-extreme heat” (22).

 Statistical analyses

This study used the mean, standard deviation, maximum, minimum, and quartiles to describe all-cause mortality, meteorological factors, and O3 in Taiyuan City from 2013 to 2022. The relationship between O3 and meteorological factors was analyzed using Pearson’s correlation and corresponding heat maps. We conducted quantitative modelling to establish the concentration-mortality associations between ambient O3 exposure and population-wide mortality outcomes, deaths due to respiratory diseases, circulatory diseases, neurological diseases, and tumors, respectively, using generalized additive models (GAMs), which controlled for long-term trends, “the day of week (DOW)” effect, and environmental determinants. Dose–response associations were subjected to stratified analytical evaluation incorporating gender-specific and age-cohort variables. We conducted lag (lag0-lag3) and cumulative lag (lag01-lag03) analyses to adjust for possible lagged impacts. Based on the results of the correlation analysis, the effects of meteorological factors on the relationships between O3 and all-cause deaths, deaths due to respiratory diseases, circulatory diseases, neurological diseases, and tumors were analyzed using GAMs with hierarchical parameters. The lagged and cumulative lagged effects of O3 were also investigated. An overdispersed Poisson regression model was employed. The models are as follow Equation 1:

log [ E ( Y t ) ] = α + β 1 ( X ) + β 2 ( M k ) + β 3 ( X : M k ) + ∑ p j = 1 fj ( Zj , df ) + W t ( DOW )

X represents the concentration of O3; Mk represents dichotomized meteorological factors; β1(X) represents the effect of O3 when the meteorological factor is the reference category; β2(Mk) represents the effect when the meteorological factor is in another category; β3(X: Mk) represents the interaction effect of O3 and meteorological factors; ∑ j = 1 p fj ( Zj , df ) is the non-parametric spline function of other variables including death date, meteorological factors, and other air pollutants. Natural cubic splines with 3 degrees of freedom were used to smooth meteorological factors and air pollutants, while natural cubic splines with 7 degrees of freedom were employed to control for long-term temporal trends. Wt(DOW) is a dummy variable for the day of the week. The effect of O3 when the meteorological factor is another category is β1+β3, and the odds ratio (OR) and corresponding 95% confidence interval are calculated. We used the “mgcv” package from R 4.0.2 software. A p < 0.05 was considered statistically significant. Model specification was selected based on the Akaike Information Criterion for the quasi-Poisson model (Q-AIC), while variable selection was consistent with previous studies (23, 24).

 Results Description of mortality, O<sub>3d</sub> and meteorological factors in Taiyuan

Table 1 shows the mortality rate in Taiyuan from 2013 to 2022. The results show that the all-cause mortality rate (7.72–13.79%), respiratory disease mortality rate (7.71–12.99%), circulatory disease mortality rate (7.65–14.50%), nervous system disease mortality rate (5.99–18.13%), and tumor mortality rate (8.22–12.33%) in Taiyuan from 2013 to 2022 exhibit an increasing trend. Table 2 included the number of daily deaths, O3 and meteorological factors, with 20.84, 12.15 and 3.82 deaths per day from circulatory diseases, tumors and respiratory diseases, respectively, being the top three. MDA8 O₃, temperature, relative humidity, precipitation, barometric pressure, wind speed and sunshine duration are 92.92 μg/m3, 11.37 °C, 57.13%, 2.59 mm, 927.24 hPa, 1.95 m/s and 7.11 h during the period from 2013 to 2022, respectively. Figure 1 illustrates the temporal changes in O3, meteorological factors, and all-cause deaths over time in Taiyuan from 2013 to 2022.

Temporal changes of O3, meteorological factors and all-cause deaths in Taiyuan from 2013 to 2019.

Multi-panel time series graph containing eight vertically aligned plots tracking different meteorological or environmental variables from January 2013 to December 2023, each with distinctive color-coded lines and scattered data patterns, some showing periodic or seasonal trends and others with sporadic spikes, all indexed against the same time axis.

Annual deaths in Taiyuan from 2013 to 2022 [n (%)].

Years Overall deaths Respiratory system disease Circulation system disease Nervous system disease Tumor
2013 12,504 (7.72) 1,075 (7.71) 5,820 (7.65) 107 (5.99) 3,647 (8.22)
2014 13,179 (8.14) 1,383 (9.92) 5,986 (7.87) 115 (6.44) 3,705 (8.35)
2015 12,445 (7.69) 1,377 (9.87) 5,521 (7.26) 94 (5.26) 3,624 (8.17)
2016 15,673 (9.68) 1,455 (10.43) 7,261 (9.54) 151 (8.45) 4,406 (9.93)
2017 15,725 (9.71) 1,539 (11.04) 7,473 (9.82) 154 (8.62) 4,393 (9.90)
2018 18,256 (11.27) 1,688 (12.10) 8,477 (11.14) 187 (10.46) 4,948 (11.15)
2019 14,654 (9.05) 1,256 (9.01) 6,422 (8.44) 169 (9.46) 4,270 (9.62)
2020 18,628 (11.50) 1,144 (8.20) 9,112 (11.97) 229 (12.81) 5,033 (11.34)
2021 18,550 (11.45) 1,217 (8.73) 8,988 (11.81) 257 (14.38) 4,877 (10.99)
2022 22,325 (13.79) 1811 (12.99) 11,031 (14.50) 324 (18.13) 5,472 (12.33)

MDA8 O₃, meteorological factors and death toll in Taiyuan from 2013 to 2022.

Variables Mean SD Min P25 P50 P75 Max
MDA8 O₃ (μg/m3) 92.92 55.15 3.69 51.29 82.86 125.71 371.71
Tem (°C) 11.37 10.58 −14.90 1.80 12.30 21.00 29.60
Hum (%) 57.13 18.93 12.00 42.00 57.00 72.00 100.00
Pre (mm) 2.59 2.61 0.00 0.00 2.44 4.44 9.95
BP (hPa) 927.24 7.00 911.40 921.20 927.60 932.60 948.90
WS (m/s) 1.95 0.99 0.30 1.20 1.70 2.40 7.20
SSD (h) 7.11 3.87 0.00 4.70 8.10 10.00 13.80
Overall deaths 44.34 15.57 3 35 43 52 271
Respiratory system disease 3.82 2.97 0 2 3 5 59
Circulation system disease 20.84 8.79 0 15 20 25 141
Nervous system disease 0.49 0.74 0 0 0 1 6
Tumor 12.15 4.15 1 9 12 15 40
Analysis of the correlation between O<sub>3</sub> and meteorological factors in Taiyuan

Our study used Pearson’s correlation to analyze the correlation between O3 and meteorological factors. Statistical analyses revealed ambient O3 concentrations demonstrated statistically significant positive associations with ambient thermal metrics and sunshine duration (Pearson’s r coefficients = 0.607, 0.282) while exhibiting inverse correlations with atmospheric pressure measurements (r = −0.552), but not strongly correlated with relative humidity, wind speed, and precipitation, as detailed in Figure 2.

Correlation heat map between O3 and meteorological factors.

Heatmap showing correlation coefficients among seven variables: ozone concentration, precipitation, barometric pressure, wind speed, sunshine duration, temperature, and humidity. Color intensity indicates correlation strength; values range from -0.827 to 1. Zero or weak correlations are pale pink, stronger positive or negative correlations are darker red. A color legend is included on the right. All-cause mortality risk and stratified analysis in Taiyuan

Figure 3 shows the death risk of O3 from lag0 to lag03 and the death risk after stratification by gender and age, respectively. The analytical findings demonstrate that ambient O3 exposure constitutes a non-negligible risk factor for elevated mortality hazards across all causes, mortality from respiratory diseases and mortality from circulatory diseases. In the all-cause mortality risk for the whole population, men and older population, the risk of death for lag2_O3 was 1.000254 (95% CI: 1.000048–1.000460), 1.000286 (95% CI: 1.000016–1.000556) and 1.000300 (95% CI: 1.000064–1.000537); the risk of death for lag3_O3 was 1.000205 (95% CI: 1.000002–1.000408), 1.000312 (95% CI: 1.000046–1.000578) and 1.000270 (95% CI: 1.0000374–1.000504); the risks of death for lag02_O3 were 1.000109 (95% CI: 1.000015–1.000202), 1.000128 (95% CI: 1.000006–1.000251) and 1.000136 (95% CI: 1.0000282–1.000243); the risks of death for lag03_O3 were 1.0000918 (95% CI: 1.000019–1.000164), 1.000118 (95% CI: 1.0000228–1.000213) and 1.000117 (95% CI: 1.0000337–1.000201), respectively (Figure 3A). The risk of death from respiratory diseases in the whole population, men and the older population, was 1.000711 (95% CI: 1.000167–1.001254), 1.001189 (95% CI: 1.000332–1.002046) and 1.000831 (95% CI: 1.000263–1.001399) for lag3_O3, respectively (Figure 3B). In the risk of death due to circulatory disease for the whole population, women, men and the older population, the risk of death for lag2_O3 was 1.000399 (95% CI: 1.000136–1.000663), 1.000408 (95% CI: 1.000088–1.000728), 1.000386 (95% CI: 1.000019–1.000752), and 1.000434 (95% CI: 1.000139–1.000729), respectively. The overall mortality risk due to circulatory disease across the population indicated that the risk associated with lag3_O3 was 1.000264 (95% CI: 1.000003–1.000524). For lag01_O3, the mortality risk from circulatory disease was found to be 1.000253 (95% CI: 1.000016–1.000489) for the general population, with values of 1.000209 (95% CI: 1.000018–1.000400) explicitly noted for males and older adults. In the risk of death due to circulatory diseases in the whole population, male and older population, the risk of death for lag02_O3 was 1.000163 (95% CI: 1.000044–1.000283), 1.000204 (95% CI: 1.000038–1.000370), and 1.000193 (95% CI: 1.000059–1.000327), and for lag03_O3 was 1.000132 (95% CI: 1.000039–1.000225), 1.000167 (95% CI: 1.0000374–1.000296) and 1.000153 (95% CI: 1.000048–1.000257) (Figure 3C). O3 had no significant effect on the population’s risk of death from neurological diseases and death from tumors (Figures 3D,E).

Risk of all-cause death and stratified risk map of causes.

This multi-panel plot shows the relative risk estimates (with error bars) of ozone exposure at lag 0–3 days for the total population, males, females, young adults and older adults, stratified by cause of death. Color-coded markers correspond to the total population, males, females, young adults and older adults, respectively. Among them, (A) all-cause mortality, (B) respiratory system disease death, (C) circulation system disease death, (D) nervous system disease death, and (E) tumor death. Analysis of the interaction between O<sub>3</sub> and meteorological factors in Taiyuan

Our study further utilized GAM with stratification parameters to analyze the mortality risk associated with O3 and the interaction between O3 and meteorological factors. Figure 4 illustrates the impact of O3 on the risk of all-cause mortality across the entire population, including men, women, and the older adults, in relation to various meteorological factors, with O3 also interacting with hours of sunlight. O3 is more likely to interact with seasons and temperature in women and the older adults. Figure 5 illustrates the impact of O3 on the risk of death from respiratory diseases in the entire population, as well as in men, women, youth, and the older adults, considering various meteorological factors. O3 interacts with the duration, season, and intensity of sunlight across the whole population, including women and the older adults. Figure 6 shows the impact of O3 on the risk of death from circulatory diseases in the entire population, men, women and the older adults, with different meteorological factors, with O3 interacting with sunshine duration in men, while O3 interacts with both season and temperature in the population as a whole, and with season in the older adults. Figure 7 shows the impact of O3 on the risk of death from neurological diseases in the whole population, males, females, youth and the older adults, with different meteorological factors, with O3 interacting with sunshine duration in the whole population, males and youth; and O3 interacting with atmospheric pressure in the whole population and females, and also with season in females. Figure 8 illustrates the effect of O3 on the risk of death from tumor in males, considering various meteorological factors. O3 interacts with sunshine duration for the entire population, including men and young people, as well as with the presence or absence of weather extremes for the entire population, women, and the older adults.

Interaction effect of all-cause death risk. Rectangles represent variables with interaction effects.

This multi-panel plot presents the relative risk estimates (with error bars) of ozone exposure at lag 0–3 days for all-cause mortality, stratified by the total population, males, females, young and older adults, under different meteorological conditions. Color-coded markers correspond to short sunshine duration, long sunshine duration, low barometric pressure, high barometric pressure, cold season, warm season, low temperature, high temperature, non extreme heat, extreme heat, respectively.

Interaction effect of respiratory system disease death risk. Rectangles represent variables with interaction effects.

This multi-panel plot presents the relative risk estimates (with error bars) of ozone exposure at lag 0–3 days for respiratory system disease mortality, stratified by the total population, males, females, young and older adults, under different meteorological conditions. Color-coded markers correspond to short sunshine duration, long sunshine duration, low barometric pressure, high barometric pressure, cold season, warm season, low temperature, high temperature, non extreme heat, extreme heat, respectively.

Interaction effect of nervous system disease death risk. Rectangles represent variables with interaction effects.

This multi-panel plot presents the relative risk estimates (with error bars) of ozone exposure at lag 0–3 days for circulation system disease mortality, stratified by the total population, males, females, young and older adults, under different meteorological conditions. Color-coded markers correspond to short sunshine duration, long sunshine duration, low barometric pressure, high barometric pressure, cold season, warm season, low temperature, high temperature, non extreme heat, extreme heat, respectively.

Interaction effect of nervous system disease death risk. Rectangles represent variables with interaction effects.

This multi-panel plot presents the relative risk estimates (with error bars) of ozone exposure at lag 0–3 days for nervous system disease mortality, stratified by the total population, males, females, young and older adults, under different meteorological conditions. Color-coded markers correspond to short sunshine duration, long sunshine duration, low barometric pressure, high barometric pressure, cold season, warm season, low temperature, high temperature, non extreme heat, extreme heat, respectively.

Interactive effect of tumor death risk. Rectangles represent variables with interaction effects.

This multi-panel plot presents the relative risk estimates (with error bars) of ozone exposure at lag 0–3 days for tumour mortality, stratified by the total population, males, females, young and older adults, under different meteorological conditions. Color-coded markers correspond to short sunshine duration, long sunshine duration, low barometric pressure, high barometric pressure, cold season, warm season, low temperature, high temperature, non extreme heat, extreme heat, respectively. Discussion

The results of our study show that the number of deaths in Taiyuan City from 2013 to 2022 exhibits a trend of slow increase year by year, which is consistent with the trend of steady increase in O3 in China as one of the air pollutants (1). Therefore, exploring the relationship between O3 and mortality risk in Taiyuan City is essential. Although the average daily O3 concentration in Taiyuan from 2013 to 2022 is 92.92 μg/m3, which is lower than China’s primary limit (100 μg/m3) and secondary limit (160 μg/m3), the time series shows periodic fluctuations. There are more periods when the O3 level is higher than China’s primary and secondary limits. We suggest that paying attention to O3 pollution levels in Taiyuan is essential to establish an early warning system and strengthen O3 prevention and control. Our study reveals significant correlations among O₃ levels, temperature, sunshine duration, and barometric pressure, likely driven by year-round influences of these meteorological factors as primary contributors to ground-level O₃ formation. Our findings align with prior studies, indicating that climatic parameters such as precipitation, humidity, and wind speed variably affect O₃ levels, with temperature/solar radiation, and relative humidity identified as key determinants in separate analyses (8, 9). Therefore, it is crucial to mitigate O3-related health risks by investigating the influence of meteorological factors on O3 levels and population mortality.

It is generally accepted that O3 has a lagged effect on population mortality. Our results show that O3 has a lag in the risk of all-cause mortality and in the risk of death due to respiratory disease, with gender- and age-stratified results showing that the lag is still present in males and older age groups. An epidemiological study found that a 10 μg/m3 increase in 24-h lagged O3 exposure correlates with a statistically significant 1.38% increase in population mortality risk (25). A longitudinal study linked a 10 μg/m3 rise in 3-day cumulative O3 exposure to a 0.24% increase in population mortality (26). The results show that for every 10 μg/m3 increase in 2-day lagged ambient O₃ exposure, the risk of all-cause mortality increases by 0.0254% (p < 0.05), with comparable risk magnitudes showing non-significant variation. Furthermore, the analytical framework quantified a statistically significant 0.0711% increase in respiratory disease-specific mortality per 10 μg/m3 rise in 3-day cumulative O₃ exposure (p < 0.01), consistent with prior correlational studies identifying lag3 O₃ as the exposure window with the highest respiratory mortality risk (27). A peer-reviewed study reported a statistically significant 0.09% elevation in respiratory disease mortality per 10 μg/m3 24-h lagged O3 exposure (p < 0.05). In comparison, a comparable epidemiological investigation demonstrated a 0.78% increase in respiratory mortality burden with 3-day cumulative O3 exposure (p < 0.01) (2, 27), which was similar to our study. This may be because O3 entering the respiratory system can exacerbate a series of responses, such as oxidative stress, inflammation, and lung injury, ultimately leading to worsening respiratory disease and death (28–30). Our analysis revealed a lagged association between ambient O3 exposure and circulatory disease mortality, persisting across gender and age subgroups. The highest risk occurred at lag 2 O3 exposure, with a 0.0399% increase in circulatory mortality per 1 μg/m3 rise (p < 0.05). Stratified analyses showed stronger female susceptibility (0.0408% vs. 0.0386% in males) and greater older adults vulnerability (0.0434% increase). A prior study reporting 0.11% mortality elevation per 10 μg/m3 lag01 O3 exposure yielded lower risk estimates than our findings (2). Still, our study spanned a considerably more extended period; the results are likely to be more realistic. It also noted that females and the older adults were more susceptible to O3 exposure. This is mainly because O3 enters the circulatory system through the blood-oxygen barrier after entering the lungs via the respiratory tract, causing vascular inflammation, oxidative damage, and vascular endothelial dysfunction (31, 32).

Meteorological factors play a crucial role in the risk of death among O3-affected populations. Our study reveals that meteorological factors contribute to the risk of O3-induced mortality from all-cause, respiratory, circulatory, and neurological diseases, including sunshine duration, season, temperature, barometric pressure, and extreme heat, with sunshine duration, season, and temperature being the primary factors. Nonetheless, the impact of O3 on tumor mortality risk was unaffected by meteorological factors. Currently, there are inconsistent findings on the effect of O3 on tumor mortality, with one study showing no significant correlation between O3 and the risk of death due to malignant tumors (33). In contrast, another study showed that O3 increases lung cancer mortality and that warm and cold seasons play an important role in this effect (34). Research on the interplay between O3 and meteorological factors in relation to tumor mortality risk remains sparse, indicating a need for further investigation. Our study, after categorizing participants by gender and age, revealed that the duration of sunshine influences the risk of mortality from tumors associated with O3 in males.

In summary, sunshine duration emerged as the primary modifier of O3-related mortality risk, with significant interactions observed between O3 exposure and meteorological factors, including barometric pressure, season, temperature, and extreme heat. Our findings align with studies demonstrating temperature-O3 synergies in ischemic heart disease pathogenesis (35) and elevated warm-season O3-associated mortality (17, 36). In general, long sunshine duration, high temperature and warm season contribute to O3’s increased mortality risk.

Our study provides scientific evidence for mitigating O3-related mortality risks by integrating meteorological factors into O3 mortality risk assessments, with a particular emphasis on sunshine duration as a key modifier. While findings support integrating meteorological data into O3 mitigation strategies, limitations persist—notably, the existing literature underscores that extreme heat amplifies O3-associated cardiovascular mortality in populations under 65, a gap warranting further investigation (28, 37). The frequency of extreme heat events in the dataset of this study was limited; thus, further expansion of the dataset is required to explore the role of extreme heat events in ozone-related mortality risk. Future work will expand the dataset to further investigate these interactions. This study provides a robust scientific foundation for informing O3 control strategies and mitigating population-level mortality risks associated with O3 exposure. Nevertheless, it is worth noting that this study has other limitations. Firstly, the collection of pollutant data relies on fixed monitoring stations, which may introduce exposure measurement bias; this is an inherent limitation in most studies (23, 38).

 Conclusion

Our study provides strong evidence that O3 increases the risk of all-cause, respiratory and circulatory mortality in the population. In addition, there were interactions between meteorological factors and O3, primarily involving sunshine duration, season, and temperature.

 Data availability statement

The data analyzed in this study is subject to the following licenses/restrictions: the datasets generated and/or analyzed during the current study are not publicly available due to data ownership by a third-party institution, but are available from the corresponding author upon reasonable request. Requests to access these datasets should be directed to ZZ, zzh1973@sxmu.edu.cn.

 Author contributions

NC: Writing – original draft, Visualization, Data curation, Validation, Conceptualization, Methodology, Writing – review & editing, Formal analysis, Software. XY: Writing – review & editing, Methodology, Data curation, Investigation. YC: Writing – original draft, Formal analysis, Writing – review & editing. LZ: Writing – review & editing, Data curation, Supervision, Funding acquisition. SG: Data curation, Writing – review & editing, Funding acquisition, Supervision. RL: Writing – review & editing, Supervision, Data curation. GZ: Data curation, Supervision, Writing – review & editing, Visualization. LM: Methodology, Data curation, Writing – review & editing. ZZ: Resources, Project administration, Funding acquisition, Supervision, Methodology, Conceptualization, Writing – review & editing.

 Acknowledgments

The authors would like to thank all participants and investigators, as well as the Chinese Centre for Disease Control and Prevention, for providing the data.

 Conflict of interest

The author(s) declared that this work was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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Edited by: Xu Zhang, Anhui Medical University, China

Reviewed by: Long Cheng, First Affiliated Hospital of Anhui Medical University, China

Qiong Duan, First Affiliated Hospital of Anhui Medical University, China

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https://air.cnemc.cn:18007/