Characterization of major chemical components.of fine. particulate matter in North Carolina
Characterization of major chemical components.of fine. particulate matter in North Carolina
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DOI：
10.1080/10473289.2006.10464529
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发表时间：
2006-08-01
影响因子：
2.7
通讯作者：
Steger, Joette
中科院分区：
文献类型：
--
作者：
Aneja, Viney P.;Wang, Binyu;Steger, Joette
本文介绍了 2002 年北卡罗来纳州 3 个城市和 1 个农村地区细颗粒物 (PM2.5) 及其主要化学成分的每日采样测量结果。无论是城市还是乡村，PM2.5 的主要不溶性成分是有机物，主要可溶性成分是硫酸盐 (SO42-)、铵 (NH4+) 和硝酸盐 (NO3-)。 NH4+主要被SO42-中和，而不是被NO3-中和，但冬季除外，此时SO42-浓度相对较低，而NO3-浓度较高。 NH4+与SO42-和NO3-之和的当量比<1，表明SO42-和NO3没有被NH4+完全中和。在农村和城市，SO42- 浓度在夏季最高，冬季最低，而 NO3- 则呈现相反的季节趋势。所有地点的 NO3- 与 SO42- 的质量比始终小于 1，这表明固定源排放可能在这些地区的 PM2.5 形成中发挥重要作用。有机碳和元素碳在三个城市地点具有良好的相关性，但在农业地点相关性较差。除了每日样本外，还在一个城市站点测量每小时样本。 PM2.5质量浓度在清晨出现峰值，在下午晚些时候出现第二个峰值。回溯轨迹分析表明，PM2.5质量含量较低的气团主要来源于海洋环境或大陆环境，但对流层高层有强烈的沉降。 PM2.5 质量浓度高的气团主要来自大陆。我们对北卡罗来纳州细颗粒物及其化学成分的研究提供了重要信息，可用于确定新的国家环境空气质量标准 (NAAQS) 对细颗粒物的有效性。此外，气体到颗粒的转化过程可以改进对污染物远距离传输和空气质量的预测。
This paper presents measurements of daily sampling of fine particulate matter (PM2.5) and its major chemical components at three urban and one rural locations in North Carolina during 2002. At both urban and rural sites, the major insoluble component of PM2.5 is organic matter, and the major soluble components are sulfate (SO42-), ammonium (NH4+), and nitrate (NO3-). NH4+ is neutralized mainly by SO42- rather than by NO3-, except in winter when SO42- concentration is relatively low, whereas NO3- concentration is high. The equivalent ratio of NH4+ to the sum of SO42- and NO3- is < 1, suggesting that SO42- and NO3 are not completely neutralized by NH4+. At both rural and urban sites, SO42- concentration displays a maximum in summer and a minimum in winter, whereas NO3- displays an opposite seasonal trend. Mass ratio of NO3- to SO42- is consistently < 1 at all sites, suggesting that stationary source emissions may play an important role in PM2.5 formation in those areas. Organic carbon and elemental carbon are well correlated at three urban sites although they are poorly correlated at the agriculture site. Other than the daily samples, hourly samples were measured at one urban site. PM2.5 mass concentrations display a peak in early morning, and a second peak in late afternoon. Back trajectory analysis shows that air masses with lower PM2.5 mass content mainly originate from the marine environment or from a continental environment but with a strong subsidence from the upper troposphere. Air masses with high PM2.5 mass concentrations are largely from continental sources. Our study of fine particulate matter and its chemical composition in North Carolina provides crucial information that may used to determine the efficacy of the new National Ambient Air Quality Standard (NAAQS) for PM fine. Moreover, the gas-to-particle conversion processes provide improved prediction of long-range transport of pollutants and air quality.