Air pollution and pneumonia hospitalization in Qingyang, China: A time-series analysis

The health hazards caused by air pollution vary significantly depending on factors such as the composition of pollutants in the region, climate, and the susceptibility of the population. Although numerous studies have explored the relationship between air quality and pneumonia, specific research evidence from a particular inland energy city like Qingyang in China is still scarce. This study aims to quantify the short-term impact of air pollution in this under-researched region on pneumonia hospitalizations. We collected the medical records of patients with pneumonia from January 1, 2015, to December 31, 2019, and also obtained data on 6 types of common air pollutants and meteorological conditions. We performed a time series analysis using a generalized additive model and a distributed nonlinear lag model. All measured data exhibited pronounced seasonality: particulate matter less than 2.5 μm in diameter, particulate matter less than 10 μm in diameter, sulfur dioxide (SO ₂ ), nitrogen dioxide (NO ₂ ), carbon monoxide (CO) concentrations and pneumonia admissions were higher in the cold season and lower in the warm season, a pattern conversely mirrored by ozone (O ₃ ) concentrations, average temperature, and relative humidity. In the single pollutant model, for every 10 μg/m ³ increase in exposure levels of particulate matter less than 2.5 μm in diameter, particulate matter less than 10 μm in diameter, SO ₂ , NO ₂ , and O ₃ 8 hours and for every 1 mg/m ³ increase in CO exposure level, the risk of pneumonia admission was 1.004 (0.991, 1.017), 1.004 (0.999, 1.010), 1.035 (1.022, 1.048), 1.221 (1.174, 1.271), 0.999 (0.981, 1.017), and 1.382 (1.230, 1.552), respectively. The strongest effects occur in lag 1, lag 7, lag 07, lag 07, lag 3, and lag 05, respectively. Our study identifies significant gender- and age-specific susceptibilities to air pollution in Qingyang. Men were more vulnerable to SO ₂ , whereas women were more affected by CO. Children aged ≤14 years constituted a high-risk group. Furthermore, we observed a distinct seasonal pattern: SO ₂ , NO ₂ , and CO were key drivers of pneumonia admissions with stronger effects in the cold season, in contrast to O ₃ , which exhibited adverse effects only during the warm season.