近年來我國多地發(fā)生嚴(yán)重霧霾天氣,，空氣動(dòng)力學(xué)直徑在2.5微米以下的顆粒物（PM2.5）被認(rèn)為是大氣污染的罪魁禍?zhǔn)?。但粒徑更小顆粒物的健康危害如何，目前尚無定論,。近日，復(fù)旦大學(xué)公共衛(wèi)生學(xué)院,、上海市大氣顆粒物污染防治重點(diǎn)實(shí)驗(yàn)室闞海東教授課題組研究證實(shí)：粒徑小于0.5微米的大氣顆粒物對(duì)人體健康危害更大，且粒徑越小,，危害越大。
相關(guān)論文已發(fā)表于公共衛(wèi)生領(lǐng)域權(quán)威期刊《環(huán)境健康展望》（Environmental Health Perspectives）,。論文第一作者孟夏介紹,，課題組在我國某城市測(cè)量了0.25~10微米（即PM0.25~PM10）范圍內(nèi)23組不同粒徑的顆粒物數(shù)量濃度，分析和比較了它們與居民健康風(fēng)險(xiǎn)的關(guān)系,。結(jié)果顯示,，粒徑在0.25~0.50微米范圍內(nèi)的顆粒物數(shù)濃度與居民健康危害，尤其是心血管疾病風(fēng)險(xiǎn)的關(guān)系最為顯著,，而粒徑大于0.50微米的顆粒物數(shù)濃度與居民健康風(fēng)險(xiǎn)沒有顯著關(guān)聯(lián)。
課題組推測(cè),，顆粒物的粒徑越小,，其對(duì)應(yīng)的數(shù)量濃度和總表面積越大,，越有可能吸附更多的有害物質(zhì)進(jìn)入人體,；也有可能與不同粒徑的顆粒物在下呼吸道的沉降方式有關(guān),，粒徑小于0.50微米的顆粒物主要以擴(kuò)散方式沉積，而大于0.50微米的顆粒物主要以撞擊方式沉積,。（生物谷Bioon.com）
生物谷推薦的英文摘要
Environmental Health Perspectives doi.org/10.1289/ehp.1103671
Fine Particulate Matter Constituents and Cardiopulmonary Mortality in a Heavily Polluted Chinese City
Junji Cao1， Hongmei Xu1,， Qun Xu2， Bingheng Chen3,， Haidong Kan3,，4
Background： Although ambient fine particulate matter (PM2.5； particulate matter ≤ 2.5 μm in aerodynamic diameter) has been linked to adverse human health effects,， the chemical constituents that cause harm are unknown. To our knowledge,， the health effects of PM2.5 constituents have not been reported for a developing country.
Objectives： We examined the short-term association between PM2.5 constituents and daily mortality in Xi’an,， a heavily polluted Chinese city.
Methods： We obtained daily mortality data and daily concentrations of PM2.5， organic carbon (OC),， elemental carbon (EC)， and 10 water-soluble ions for 1 January 2004 through 31 December 2008. We also measured concentrations of fifteen elements 1 January 2006 through 31 December 2008. We analyzed the data using overdispersed generalized linear Poisson models.
Results： During the study period,， the mean daily average concentration of PM2.5 in Xi’an was 182.2 μg/m3. Major contributors to PM2.5 mass included OC,， EC， sulfate,， nitrate， and ammonium. After adjustment for PM2.5 mass,， we found significant positive associations of total,， cardiovascular， or respiratory mortality with OC,， EC， ammonium,， nitrate， chlorine ion,， chlorine,， and nickel for at least one lag period. Nitrate demonstrated stronger associations with total and cardiovascular mortality than PM2.5 mass. For a 1-day lag， interquartile range increases in PM2.5 mass and nitrate (114.9 and 15.4 μg/m3,， respectively) were associated with 1.8% [95% confidence interval (CI)： 0.8%， 2.8%] and 3.8% (95% CI： 1.7%,， 5.9%) increases in total mortality.
Conclusions： Our findings suggest that PM2.5 constituents from the combustion of fossil fuel may have an appreciable influence on the health effects attributable to PM2.5 in Xi’an.
