Impact of the 2002 Canadian forest fires on particulate matter air quality in Baltimore City
Impact of the 2002 Canadian forest fires on particulate matter air quality in Baltimore City
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DOI：
10.1021/es035311z
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发表时间：
2005-01-01
影响因子：
11.4
通讯作者：
Buckley, TJ
中科院分区：
文献类型：
--
作者：
Sapkota, A;Symons, JM;Buckley, TJ
随着越来越多的证据表明颗粒物（PM）对健康有不良影响，森林火灾等自然源的暴露影响与公共健康密切相关。除了对附近社区构成威胁外，森林火灾释放的污染物还能传播数千公里到达人口密集的城市地区。2002年7月，加拿大魁北克省的森林火灾活动急剧增加。利用中分辨率成像光谱仪卫星图像、混合单粒子拉格朗日综合轨迹的后向轨迹以及当地的光探测和测距测量相结合的方法，对这些森林火灾释放的颗粒物的传输进行了研究。在三个环境监测点和四个室内监测点，使用直读式仪器（激光、飞行时间气溶胶光谱仪、浊度计和振荡微天平）对按时间和粒径分辨的颗粒物进行了评估。传输和监测结果一致表明，2002年7月的第一个周末，巴尔的摩发生了一次与森林火灾有关的颗粒物事件，导致环境细颗粒物增加了多达30倍。根据锥形元件振荡微天平的测量结果，2002年7月7日，24小时PM2.5浓度达到86微克/立方米，超过了24小时国家环境空气质量标准。该事件主要由空气动力学直径小于2.5微米的颗粒物组成，凸显了对健康危害最大的那部分颗粒物的优先传输。环境事件在室内的穿透效率很高（室内外比值中位数为0.91），因此室内也经历了类似的高环境水平。这些结果对于证明数千公里外的自然源对城市中心的环境空气污染水平和潜在暴露的影响具有重要意义。这项研究凸显了跨界空气污染的重要性，以及开展评估此类污染源和传输过程对公共健康影响的研究的必要性。
With increasing evidence of adverse health effects associated with particulate matter (PM), the exposure impact of natural sources, such as forest fires, has substantial public health relevance. In addition to the threat to nearby communities, pollutants released from forest fires can travel thousands of kilometers to heavily populated urban areas. There was a dramatic increase in forest fire activity in the province of Quebec, Canada, during July 2002. The transport of PM released from these forest fires was examined using a combination of a moderate-resolution imaging spectroradiometer satellite image, back-trajectories using a hybrid single-particle Lagrangian integrated trajectory, and local light detection and ranging measurements. Time- and size-resolved PM was evaluated at three ambient and four indoor measurement sites using a combination of direct reading instruments (laser,time-of-flight aerosol spectrometer, nephelometer, and an oscillating microbalance). The transport and monitoring results consistently identified a forest fire related PM episode in Baltimore that occurred the first weekend of July 2002 and resulted in as much as a 30-fold increase in ambient fine PM.. On the basis of tapered element oscillating microbalance measurements, the 24 h PM2.5 concentration reached 86 mug/m(3) on July 7, 2002, exceeding the 24 h national ambient air quality standard. The episode was primarily comprised of particles less than 2.5 mum in aerodynamic diameter, highlighting the preferential transport of the fraction of PM that is of greatest health concern. Penetration of the ambient episode indoors was efficient (median indoor-to-outdoor ratio 0.91) such that the high ambient levels were similarly experienced indoors. These results are significant in demonstrating the impact of a natural source thousands of kilometers away on ambient levels of and potential exposures to air pollution within an urban center. This research highlights the significance of transboundary air pollution and the need for studies that assess the public health impacts associated with such sources and transport processes.