Classroom indoor PM2.5 sources and exposures in inner-city schools
Classroom indoor PM2.5 sources and exposures in inner-city schools
复制标题
DOI：
10.1016/j.envint.2019.104968
复制
发表时间：
2019-10-01
影响因子：
11.8
通讯作者：
Gold, Diane R.
中科院分区：
文献类型：
--
作者：
Carrion-Matta, Aleshka;Kang, Choong-Min;Gold, Diane R.
儿童每天在学校呆的时间超过 6 小时，因学校环境暴露而导致哮喘发病率较高。本研究旨在确定影响教室室内 PM2.5 的室内和室外可能来源。 2009 年至 2013 年三个季节（秋季、冬季和春季）从美国东北部社区的 32 所市中心学校采集了为期一周的室内 PM2.5 样本。同时，在距离学校中位距离 4974m（范围 1065-11,592 m）的中央监测点每日采集室外 PM2.5 样本。教室室内PM2.5浓度（平均5.2μg/m(3)）低于室外（平均6.5μg/m(3)），与其他学校的研究结果相比，这些平均值处于较低范围内。 USEPA PMF 模型应用于在教室室内和室外同时测量的 PM2.5 成分，以估计源解析。各季节室内 PM2.5 的主要来源（贡献）是二次污染（41%）和机动车（17%），其次是富钙（Ca）颗粒（12%）、生物质燃烧（15%）、土壤灰尘（6%）和海洋气溶胶（4%）。同样，各季节室外PM2.5的主要来源是二次污染（41%）和机动车（26%），其次是生物质燃烧（17%）、土壤扬尘（7%）、道路扬尘（3%）和海洋气溶胶（1%）。二次污染是三个季节室内和室外 PM2.5 的最大贡献者，其中春季贡献最高，室内 PM2.5 占 53%，室外 PM2.5 占 45%。秋季和冬季该来源的贡献较低很可能是由于室内渗透较少。相比之下，机动车源的室内贡献在秋季（29%）和冬季（25%）最高，这可能是按当地源分类的。从室内外硫比与各源贡献之间的关系，我们还估计了局部和区域对室内PM2.5浓度的影响。总体而言，观察到的室内 PM2.5 差异与季节性以及每个教室/学校的独特特征和行为有关。
Children spend over 6 h a day in schools and have higher asthma morbidity from school environmental exposures. The present study aims to determine indoor and outdoor possible sources affecting indoor PM2.5 in classrooms. Weeklong indoor PM2.5 samples were collected from 32 inner-city schools from a Northeastern U.S. community during three seasons (fall, winter and spring) during the years 2009 to 2013. Concurrently, daily outdoor PM2.5 samples were taken at a central monitoring site located at a median distance of 4974m (range 1065-11,592 m) from the schools. Classroom indoor concentrations of PM2.5 (an average of 5.2 mu g/m(3)) were lower than outdoors (an average of 6.5 mu g/m(3)), and these averages were in the lower range compared to the findings in other schools' studies. The USEPA PMF model was applied to the PM2.5 components measured simultaneously from classroom indoor and outdoor to estimate the source apportionment. The major sources (contributions) identified across all seasons of indoor PM2.5 were secondary pollution (41%) and motor vehicles (17%), followed by Calcium (Ca)-rich particles (12%), biomass burning (15%), soil dust (6%), and marine aerosols (4%). Likewise, the major sources of outdoor PM2.5 across all seasons were secondary pollution (41%) and motor vehicles (26%), followed by biomass burning (17%), soil dust (7%), road dust (3%), and marine aerosols (1%). Secondary pollution was the greatest contributor to indoor and outdoor PM2.5 over all three seasons, with the highest contribution during spring with 53% to indoor PM2.5 and 45% to outdoor PM2.5. Lower contributions of this source during fall and winter are most likely attributed to less infiltration indoors. In contrast, the indoor contribution of motor vehicles source was highest in the fall (29%) and winter (25%), which was presumably categorized by a local source. From the relationship between indoor-to-outdoor sulfur ratios and each source contribution, we also estimated the local and regional influence on indoor PM2.5 concentration. Overall, the observed differences to indoor PM2.5 are related to seasonality, and the distinct characteristics and behavior of each classroom/school.