Patel Molini M, Chillrud Steven N, Correa Juan C, Feinberg Marian, Hazi Yair, Kc Deepti, Prakash Swati, Ross James M, Levy Diane, Kinney Patrick L
Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine College of Physicians and Surgeons, Columbia University 8E, 630 West 168 Street New York, NY 10032, USA
Atmos Environ (1994). 2009 Oct;43(32):4975-4981. doi: 10.1016/j.atmosenv.2009.07.004.
Relatively little is known about exposures to traffic-related particulate matter at schools located in dense urban areas. The purpose of this study was to examine the influences of diesel traffic proximity and intensity on ambient concentrations of fine particulate matter (PM(2.5)) and black carbon (BC), an indicator of diesel exhaust particles, at New York City (NYC) high schools. Outdoor PM(2.5) and BC were monitored continuously for 4-6 weeks at each of 3 NYC schools and 1 suburban school located 20 kilometers upwind of the city. Traffic count data were obtained using an automated traffic counter or video camera. BC concentrations were 2-3 fold higher at urban schools compared with the suburban school, and among the 3 urban schools, BC concentrations were higher at schools located adjacent to highways. PM(2.5) concentrations were significantly higher at urban schools than at the suburban school, but concentrations did not vary significantly among urban schools. Both hourly average counts of trucks and buses and meteorological factors such as wind direction, wind speed, and humidity were significantly associated with hourly average ambient BC and PM(2.5) concentrations in multivariate regression models. An increase of 443 trucks/buses per hour was associated with a 0.62 mug/m(3) increase in hourly average BC at a NYC school located adjacent to a major interstate highway. Car traffic counts were not associated with BC. The results suggest that local diesel vehicle traffic may be important sources of airborne fine particles in dense urban areas and consequently may contribute to local variations in PM(2.5) concentrations. In urban areas with higher levels of diesel traffic, local, neighborhood-scale monitoring of pollutants such as BC, which compared to PM(2.5), is a more specific indicator of diesel exhaust particles, may more accurately represent population exposures.
对于位于人口密集城市地区的学校周边与交通相关的颗粒物暴露情况，人们了解相对较少。本研究的目的是考察纽约市（NYC）各高中柴油交通的距离和强度对环境空气中细颗粒物（PM₂.₅）浓度以及柴油车尾气颗粒指标黑碳（BC）浓度的影响。在纽约市的3所学校以及位于城市上风20公里处的1所郊区学校，对室外PM₂.₅和BC进行了连续4至6周的监测。使用自动交通计数器或摄像机获取交通流量数据。与郊区学校相比，城市学校的BC浓度高出2至3倍，在3所城市学校中，靠近高速公路的学校BC浓度更高。城市学校的PM₂.₅浓度显著高于郊区学校，但各城市学校之间的浓度没有显著差异。在多变量回归模型中，每小时卡车和公交车的平均数量以及风向、风速和湿度等气象因素均与每小时环境BC和PM₂.₅的平均浓度显著相关。在一所毗邻主要州际公路的纽约市学校，每小时卡车/公交车数量增加443辆与每小时平均BC浓度增加0.62微克/立方米相关。汽车交通流量与BC无关。结果表明，当地柴油车辆交通可能是人口密集城市地区空气中细颗粒物的重要来源，因此可能导致PM₂.₅浓度的局部差异。在柴油交通水平较高的城市地区，对BC等污染物进行局部、邻里尺度的监测，与PM₂.₅相比，BC是柴油车尾气颗粒更具体的指标，可能更准确地反映人群暴露情况。
