Estimation of the monthly average ratios of organic mass to organic carbon for fine particulate matter at an urban site
Estimation of the monthly average ratios of organic mass to organic carbon for fine particulate matter at an urban site
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DOI：
10.1080/02786820601004085
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发表时间：
2006-12-01
影响因子：
5.2
通讯作者：
Turner, Jay R.
中科院分区：
文献类型：
--
作者：
Bae, Min-Suk;Schauer, James J.;Turner, Jay R.
使用两种独立的方法来估计在圣路易斯-中西部Supersite收集的大气颗粒物中细颗粒有机物（OM）与细颗粒有机碳（OC）之比的季节性。第一种方法假设所有不能归因于硫酸根离子、硝酸根离子、铵离子、元素碳和金属氧化物的细颗粒物质量都是有机物。使用这种方法，98个每日样本被用来估计年平均细颗粒物OM/OC比为1.81 +/- 0.07，夏季平均值为1.95 +/- 0.17，冬季平均值为1.77 +/- 0.13。第二种估算细颗粒物OM/ OC的方法采用OC源解析结果和源特异性OM/ OC的估算，包括一次源和二次有机气溶胶。有机物质/有机碳的估算是根据两年期间98个每日源分配计算得出的，年平均比率为1.96 +/- 0.03。研究中使用的方法产生了圣路易斯地区细颗粒物OM/ OC比值的相对稳定的年平均估计值。源解析结果表明，圣路易斯在夏季和冬季的相似的OM/ OC比的结果增加的相对贡献的二次有机气溶胶在夏季的几个月，是平衡的较高的木烟在冬季。尽管为圣路易斯确定的估计OM/ OC比率不能直接应用于其他地点，但考虑到这些计算所需的数据，用于估计OM/ OC的方法可以广泛应用。
Two independent methods are used to estimate the seasonality of the ratio of fine particulate organic matter ( OM) to fine particulate organic carbon (OC) for atmospheric particulate matter collected at the St. Louis - Midwest Supersite. The first method assumes that all of the fine particulate matter mass that cannot be attributed to sulfate ion, nitrate ion, ammonium ion, elemental carbon and metal oxides is organic matter. Using this method, 98 daily samples were used to estimate the annual average fine particulate matter OM/OC ratio to be 1.81 +/- 0.07 with a summer average of 1.95 +/- 0.17 and a winter average of 1.77 +/- 0.13. The second approach to estimating fine particle OM/ OC employed OC source apportionment results and estimates of source specific OM/ OC, including primary sources and secondary organic aerosol. The OM/ OC estimate that was based on 98 daily source apportionment calculations over a two year period yielded an annual average ratio of 1.96 +/- 0.03. Methods used in the study yielded a relatively stable annual average estimate of the OM/ OC ratio for fine particulate matter in the St. Louis area. The source apportionment results indicate that the similar OM/ OC ratio for St. Louis in the summer and winter results from an increased relative contribution of secondary organic aerosol in the summer months that is balanced by the higher woodsmoke in the winter. Although the estimated OM/ OC ratios that were determined for St. Louis cannot be directly applied to other locations, the methodologies used to estimate OM/ OC can be broadly applied given the necessary data for these calculations.