中国4个城市大气臭氧对呼吸系统疾病住院人数影响的时间序列分析

臭氧已成为影响中国空气质量最重要的污染物之一，为探究其对呼吸系统疾病住院人数的影响，收集保定、盐城、自贡和广州4个城市2019—2022年逐日因呼吸疾病住院人数、臭氧日最大8 h平均浓度（O₃-8h）和气象因素数据，采用广义相加模型在城市水平分析大气O₃-8h与呼吸系统疾病日住院人数的关联性，并采用随机效应Meta分析整合城市水平分析结果。结果表明：大气臭氧浓度升高可增加呼吸系统疾病日住院人数，并存在滞后效应；城市合并分析结果显示，O₃-8h每升高10 μg∙m⁻³，总呼吸系统疾病、慢性阻塞性肺病（COPD）和肺炎日住院人数分别增加0.49%（95%置信区间（CI）：0.30%—0.68%，滞后3 d）、0.86%（95% CI：0.54%—1.18%，滞后2 d）和0.74%（95% CI：0.31%—1.17%，滞后4 d）。不同城市的效应强度以及最佳滞后时间存在较大差异；总体上，儿童和≥60岁老年人群对臭氧的呼吸系统效应更为敏感，不同性别间敏感性无显著差异。

A time-series analysis of the effect of atmospheric ozone on hospitalization of residents with respiratory diseases in four Chinese cities

Background, aim, and scope In recent years, ozone has emerged as a significant pollutant impacting air quality in China. Variations in the effects of short-term ozone exposure on respiratory disease incidence may exist regionally. Nevertheless, there is a noticeable lack of studies encompassing multiple cities in this area. The primary goal of this research was to examine the influence of atmospheric ozone on the incidence of hospital admissions for respiratory diseases in several Chinese cities. Materials and methods Data on daily maximum 8-h average concentrations of ozone (O₃-8h), meteorological conditions, and hospital admissions for respiratory diseases were gathered from January 1, 2019, to December 31, 2022, in four Chinese cities: Baoding, Yancheng, Zigong, and Guangzhou. The relationship between daily hospital admissions for respiratory diseases and atmospheric O₃-8h concentrations was examined at the city level using a generalized additive model. This analysis adjusted for long-term and seasonal trends, meteorological conditions, the “day-of-the-week effect”, and the “holiday effect”. A random-effects meta-analysis was employed to synthesize the findings at the city level. Results The impact of ozone on hospital admissions for respiratory diseases was found to be delayed, with the severity of the impact varying significantly across cities. For each 10 μg·m⁻³ increase in atmospheric O₃-8h concentration, the percentage of daily hospitalizations for all respiratory diseases, chronic obstructive pulmonary disease (COPD), and pneumonia increased by 0.35% (Guangzhou)—1.11% (Zigong), 0.54% (Baoding)—1.42% (Yancheng), and 0.42% (Guangzhou)—1.37% (Zigong), respectively in different cities, with most effects being statistically significant (P＜0.05). At the multi-city level, for each 10 μg·m⁻³ increase in O₃-8h concentration, daily hospital admissions for respiratory diseases increased by 0.49% (95% CI: 0.30%—0.68%, lag3), 0.86% (95% CI: 0.54%—1.18%, lag2), and 0.74% (95% CI: 0.31%—1.17%, lag4). Stratification analysis revealed that children and the elderly aged 60 years or older were especially susceptible, with no notable differences in susceptibility between genders. The significance of the ozone effect was maintained in a dual-pollutant model that controlled for the presence of other pollutants. Discussion An increase in atmospheric ozone concentration has consistently led to an uptick in hospital admissions for respiratory ailments, with more pronounced effects generally observed in southern cities compared to northern ones. This difference may be partly due to regional variations in ozone infiltration rates. The lagged effect of ozone was also observed, which can be attributed to ozone’s chemical and toxicological properties, along with the time lapse between residents falling ill and hospital admission. Vulnerability to ozone’s health effects was heightened among elderly populations with diminished respiratory and immune functions, as well as children with underdeveloped respiratory and immune functions and increased pollutant exposure per unit of body weight. Conclusions Short-term ozone exposure has been linked to increased hospitalizations for respiratory diseases, showing both delayed effects and regional discrepancies. Recommendations and perspectives Considering the substantial link between atmospheric ozone and respiratory diseases, more rigorous actions should be implemented to curb the further worsening of ozone pollution. Additionally, the establishment of an early warning system for ozone-polluted weather could aid in advising vulnerable populations, particularly the elderly and children, on effective measures to mitigate health risks associated with ozone exposure.