Positive sampling artifacts in particulate organic carbon measurements in roadside environment

被引:1
作者
Yan Cheng
Shun Cheng Lee
Kin Fai Ho
Kochy Fung
机构
[1] Xi’an Jiaotong University,Department of Environmental Science and Technology, School of Human Settlements and Civil Engineering
[2] Institute of Earth Environment,State Key Laboratory of Loess and Quaternary Geology
[3] CAS,Department of Civil and Structural Engineering, Research Center for Environmental Technology and Management
[4] Hong Kong Polytechnic University,undefined
[5] Atmoslytic Inc.,undefined
来源
Environmental Monitoring and Assessment | 2010年 / 168卷
关键词
Positive artifacts; PM; PM; PM; Roadside;
D O I
暂无
中图分类号
学科分类号
摘要
The positive artifacts in particulate organic carbon measurements in a roadside environment were characterized using two filters in tandem. The experiments were performed for PM1.0, PM2.5, and PM10 at 24-h interval using a URG sampler, followed by organic carbon (OC)/ elemental carbon (EC) analysis by the Interagency Monitoring of Protected Visual Environments thermal/optical reflectance carbon analysis protocol. The OC concentrations, derived from the quartz filter behind a front quartz filter, were quite similar for PM1.0, PM2.5, and PM10, ranging from 0.6 to 2.7 μg C m − 3 for PM1.0, from 0.7 to 2.7 μg C m − 3 for PM2.5, and from 1.1 to 2.7 μg C m − 3 for PM10. They were respectively ~2.8%, ~2.4%, and ~1.6% of the particulate mass. The most abundant species on the backup quartz filters were OC2 (250°C) and OC3 (450°C), accounting for ~80% of measured organic carbon on the backup quartz filters. It indicates the filter artifacts are mainly composed of adsorbed semi-volatile organics (below the analysis temperature of 450°C) including gaseous and particulate phase; the loading of artifacts depends on the nature of vapor and its interaction with filter substrate, rather than particle sizes. The uncorrected OC/EC ratios on the front quartz filters were ~10% higher than the corrected OC/EC ratios by positive organic artifacts in winter, and it is ~20% higher in summer. Another finding is that the separation distance of the front and backup filters influence the level of artifacts assessed by the backup filter.
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页码:645 / 656
页数:11
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