论文部分内容阅读
[背景]空气中的颗粒与健康结局之间的关联已在全球范围内广为报道。然而,有关不同大小的颗粒对健康影响的信息却十分有限。[目的]探讨在中国沈阳,分粒级粒子数浓度(PNCs)与每日死亡率之间的关联。[方法]收集2006年12月1日至2008年11月30日期间,有关死因别死亡率和颗粒直径为0.25~10μm PNCs的每日数据。用准泊松回归广义相加模型来估计PNCs与死亡率之间的关联,并用自然样条平滑函数校正随时间变化的协变量和长期及季节性趋势。[结果]因所有自然原因、心血管疾病、呼吸系统疾病所致的每日死亡平均例数分别为67、32和7。颗粒直径在0.25~0.50μm的PNCs的四分位间距(IQR)增加与总死亡率和心血管疾病死亡率显著相关,但与呼吸系统疾病死亡率无相关性。与凉爽的季节相比,温暖的季节里PNCs效应估计值较大,并且随着颗粒粒径的减小而增加。颗粒大小为0.25~0.28μm、0.35~0.40μm和0.45~0.50μm的PNCs的IQR增加,总死亡率分别增加2.41%(95%CI:1.23%~3.58%)、1.31%(95%CI:0.52%~2.09%)和0.45%(95%CI:0.04%~0.87%)。经校正大气颗粒物和气态污染物的质量浓度后,这种关联总体保持稳定。[结论]研究结果提示,颗粒直径<0.5μm的颗粒可能是空气污染微粒中导致健康不利影响的最主要成分,并且它们对健康的不利影响随着颗粒直径的减小而增加。
[Background] The association between airborne particles and health outcomes has been widely reported worldwide. However, the information on the health effects of particles of different sizes is very limited. [Objective] To explore the correlation between fractional particle concentration (PNCs) and daily mortality in Shenyang, China. [Method] The daily data on death-specific mortality and PNCs with particle diameter of 0.25 ~ 10μm were collected from December 1, 2006 to November 30, The quasi-Poisson regression model of generalized summation was used to estimate the association between PNCs and mortality, and covariates and long-term and seasonal trends were corrected with time using natural spline smoothing functions. [Results] The average daily deaths due to cardiovascular diseases and respiratory diseases due to all natural causes were 67, 32 and 7, respectively. The increase in interquartile range (IQR) of PNCs with particle diameters between 0.25 and 0.50 μm was significantly associated with overall and cardiovascular mortality but not with respiratory disease mortality. Compared with the cool season, the PNCs effect in the warm season is estimated to be larger and increases as the particle size decreases. The IQR of PNCs with particle size of 0.25 ~ 0.28μm, 0.35 ~ 0.40μm and 0.45 ~ 0.50μm increased with the increase of 2.41% (95% CI: 1.23% ~ 3.58%) and 1.31% (95% CI: 0.52% % ~ 2.09%) and 0.45% (95% CI: 0.04% ~ 0.87%). After correlating the mass concentrations of atmospheric particulates and gaseous pollutants, the correlation remained generally stable. [Conclusions] The results suggest that particles with particle size <0.5 μm may be the most important components of airborne particles that cause adverse health effects, and their adverse health effects increase with decreasing particle diameter.