Particulate carbon measurements in California's San Joaquin Valley
Particulate carbon measurements in California's San Joaquin Valley
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DOI：
10.1016/j.chemosphere.2005.04.094
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发表时间：
2006-01-01
期刊：
影响因子：
8.8
通讯作者：
Magliano, KL
中科院分区：
文献类型：
--
作者：
Chow, JC;Watson, JG;Magliano, KL
在加州区域PM10/PM2.5空气质量研究（CRPAQS）和弗雷斯诺Supersite项目期间，对气溶胶碳采样方法和偏差进行了评估。PM2.5采样进行了使用沙漠研究所（DRI）连续过滤器采样器（SFS）从1999年12月至2001年2月在两个城市网站（弗雷斯诺和贝克斯菲尔德），一个区域运输网站（Angiola），和两个边界网站（贝瑟尔岛和塞拉内华达州山麓）在圣华金河谷（SJV）的CRPAQS。作为美国环境保护署（EPA）超级站点计划的一部分，在弗雷斯诺进行了额外的基于过滤器的采样。有机碳（OC）和元素碳（EC）浓度在冬季（12月至2月）高于夏季（6月至8月），这种趋势在弗雷斯诺和贝克斯菲尔德最明显。OC和EC表现出类似的昼夜变化趋势，在冬季和夏季在弗雷斯诺和冬季在Angiola。在Angiola的昼夜模式反映了二次污染物的运输到现场。在弗雷斯诺用DRI SFS和Andersen FRM及RAAS取样器对未剥层石英纤维过滤器上的OC和EC进行了同位测量。采样器之间OC的所有平均差异均小于其各自的测量不确定度。在弗雷斯诺使用Andersen RAAS采样器（带有碳洁净和未洁净通道，带有聚四氟乙烯膜和石英纤维过滤器对）评价了正和负OC偏倚。裸露的颗粒OC之间的差异，并通过减去石英后聚四氟乙烯或石英后石英OC从未裸露的石英纤维前过滤器在大多数情况下，小于其测量不确定性的两倍。裸露通道中的颗粒OC与未裸露前和备用石英纤维OC之间的差异最接近。(c)2005爱思唯尔有限公司保留所有权利。
Aerosol carbon sampling methods and biases were evaluated during the California Regional PM10/PM2.5 Air Quality Study (CRPAQS) and Fresno Supersite programs. PM2.5 sampling was conducted using Desert Research Institute (DRI) sequential filter samplers (SFS) from December 1999 through February 2001 at two urban sites (Fresno and Bakersfield), one regional transport site (Angiola), and two boundary sites (Bethel Island and Sierra Nevada Foothills) during CRPAQS in the San Joaquin Valley (SJV). Additional filter-based sampling was done in Fresno as part of the US Environmental Protection Agency (EPA) Supersites program. Organic carbon (OC) and elemental carbon (EC) concentrations were higher during winter (December-February) than summer (June-August) and this trend was most pronounced at Fresno and Bakersfield. OC and EC displayed similar diurnal trends during winter and summer at Fresno and during winter at Angiola. The diurnal pattern at Angiola reflected the transport of secondary pollutants to the site. Collocated measurements of OC and EC on undenuded quartz-fiber filters were made at Fresno with the DRI SFS and the Andersen FRM and RAAS samplers. All average differences in OC between samplers were less than their respective measurement uncertainties. Positive and negative OC biases were evaluated at Fresno using the Andersen RAAS sampler with carbon-denuded and undenuded channels with Teflon-membrane and quartz-fiber filter pairs. Differences between the denuded particle OC and that obtained by subtracting the quartz-behind-Teflon or quartz-behind-quartz OC from the undenuded quartz-fiber front filter were less than twice their measurement uncertainties in most cases. Particulate OC in the denuded channel agreed most closely with the difference between undenuded front and backup quartz-fiber OC. (c) 2005 Elsevier Ltd. All rights reserved.