SKJ Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, and Centre for Environment and Health, Peking University, Beijing, China.
Environ Health Perspect. 2012 Mar;120(3):393-8. doi: 10.1289/ehp.1103715. Epub 2011 Dec 8.
Epidemiologic studies have attributed adverse health effects to air pollution; however, controversy remains regarding the relationship between ambient oxidants [ozone (O₃) and nitrogen dioxide (NO₂)] and mortality, especially in Asia. We conducted a four-city time-series study to investigate acute effects of O₃ and NO₂ in the Pearl River Delta (PRD) of southern China, using data from 2006 through 2008.
We used generalized linear models with Poisson regression incorporating natural spline functions to analyze acute mortality in association with O₃ and NO₂, with PM₁₀ (particulate matter ≤ 10 μm in diameter) included as a major confounder. Effect estimates were determined for individual cities and for the four cities as a whole. We stratified the analysis according to high- and low- exposure periods for O₃.
We found consistent positive associations between ambient oxidants and daily mortality across the PRD cities. Overall, 10-μg/m³ increases in average O₃ and NO₂ concentrations over the previous 2 days were associated with 0.81% [95% confidence interval (CI): 0.63%, 1.00%] and 1.95% (95% CI: 1.62%, 2.29%) increases in total mortality, respectively, with stronger estimated effects for cardiovascular and respiratory mortality. After adjusting for PM₁₀, estimated effects of O₃ on total and cardiovascular mortality were stronger for exposure during high-exposure months (September through November), whereas respiratory mortality was associated with O₃ exposure during nonpeak exposure months only.
Our findings suggest significant acute mortality effects of O₃ and NO₂ in the PRD and strengthen the rationale for further limiting the ambient pollution levels in the area.
流行病学研究认为空气污染对健康有不良影响；然而，环境氧化剂（臭氧[O3]和二氧化氮[NO2]）与死亡率之间的关系仍存在争议，尤其是在亚洲。我们开展了一项珠三角（中国南部）四城市时间序列研究，利用 2006 年至 2008 年的数据，调查 O3 和 NO2 的急性效应。
我们使用广义线性模型和泊松回归，结合自然样条函数，分析 O3 和 NO2 与急性死亡率之间的关系，将 PM10（直径≤10μm 的颗粒物）作为主要混杂因素。个体城市和四个城市整体的效应估计值都进行了分析。我们根据 O3 的高暴露期和低暴露期进行分层分析。
我们发现，珠三角城市的环境氧化剂与每日死亡率之间存在一致的正相关关系。总体而言，前两天平均 O3 和 NO2 浓度每增加 10μg/m3，总死亡率分别增加 0.81%（95%置信区间：0.63%，1.00%）和 1.95%（95%置信区间：1.62%，2.29%），心血管和呼吸死亡率的估计效应更强。调整 PM10 后，O3 对总死亡率和心血管死亡率的影响在高暴露月份（9 月至 11 月）更强，而呼吸死亡率仅与非高峰期 O3 暴露有关。
我们的研究结果表明，O3 和 NO2 在珠三角地区有显著的急性死亡率效应，这进一步强化了限制该地区环境污染物水平的合理性。
