天津市老年人PM2.5个体暴露化学组分特征

分别于2011年6月13日—7月2日(夏季)和11月30日—12月12日(冬季),采用颗粒物个体暴露采样器对天津市某社区101名老年人(平均年龄67岁)的PM_2.5个体暴露水平进行监测,以探讨PM_2.5个体暴露化学组分的特征. 结果表明,天津市老年人夏、冬季PM_2.5个体暴露浓度分别为(124.2±75.2)和(170.8±126.6)μg/m3. 斯皮尔曼相关分析表明,Si、NH₄+和NO₃-的暴露浓度均与PM_2.5暴露浓度显著相关(P<0.01),R(相关系数)分别为0.61、0.55和0.46. 富集因子分析表明,Cd、Zn和Pb 3种元素高度富集,受人为源的影响强烈. SO₄2-是水溶性离子中含量最高的组分,其次是NO₃-和NH₄+,在夏、冬季这3种离子暴露浓度之和分别占PM_2.5暴露浓度的34.3%和40.6%. OC是老年人PM_2.5个体暴露的主要成分之一,夏、冬季OC暴露浓度分别占PM_2.5暴露浓度的19.3%和27.4%. 老年人PM_2.5个体暴露化学组分浓度受气象因素、室内源和室外源的共同影响,季节变化明显. 冬季Al、Si、K、Ca和Fe的暴露浓度高于夏季,但大部分微量金属元素(V、Cr、Mn、Ni、Cu、Zn、As、Sb和Pb)的冬季暴露浓度却低于夏季. 方差分析表明,冬季SO₄2-、NO₃-、NH₄+、OC和EC的暴露浓度显著高于夏季(P<0.05). 

Chemical Compositions Characteristics of Personal PM2.5 Exposure for an Elderly Subpopulation in Tianjin City

To investigate exposure characteristics of PM_2.5, a panel study was conducted for elderly subpopulation in Tianjin City, using particulate matter personal exposure monitors. One hundred and one elderly participants (mean age:67) were selected and monitored longitudinally in summer (13th June-2nd July) and winter (30th November-12th December) of 2011. The results showed that the personal PM_2.5 mass concentrations were (124.2±75.2) μg/m3, (170.8±126.6) μg/m3 for summer and winter, respectively. The result of Spearman correlation analysis showed that concentration of Si (R=0.61), NH₄+(R=0.55) and NO₃-(R=0.46) had significant correlations (P<0.01) with PM2.5 mass concentration. In addition, enrichment factor analysis addressed high concentrations of Cd, Zn and Pb, this indicated that the results were notably affected by anthropogenic sources. The anion SO₄2- was the most predominant water soluble ions followed by NO₃- and NH₄+. The sum of SO₄2-, NO₃-, NH₄+ concentration accounting for 40.6%, 34.3% of the PM_2.5 mass concentration in winter and summer, respectively. OC was also the major component of personal PM_2.5 with percentages of 27.4%, 19.3% in winter and summer, respectively. Concentrations of personal PM_2.5 chemical compositions were mainly effected by meteorological factors including indoor and outdoor sources with great seasonal variations. Concentrations of crustal elements including Al, Si,K,Ca and Fe in winter were higher than in summer while concentrations of most trace elements including V,Cr,Mn,Ni,Cu,Zn,As,Sb and Pb appeared reversely higher in summer. ANOVA analysis showed that concentrations of SO₄2-, NO₃-, NH₄+, OC and EC were significantly higher in winter than those in summer (P<0.05).