Estimation of secondary organic aerosol formation from semi-continuous OC–EC measurements in a Madrid suburban area
Estimation of secondary organic aerosol formation from semi-continuous OC–EC measurements in a Madrid suburban area
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DOI：
10.1016/j.atmosenv.2005.11.007
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发表时间：
2006-02
影响因子：
5
通讯作者：
J. Plaza;F. J. Gómez-Moreno;L. Núñez;M. Pujadas;B. Artíñano
中科院分区：
文献类型：
--
作者：
J. Plaza;F. J. Gómez-Moreno;L. Núñez;M. Pujadas;B. Artíñano
分析每小时测量的气态污染物和细碳气溶胶（PM2.5）分为两个部分，元素和有机碳（EC和OC），在郊区马德里大都市区的网站。在2003年的夏季和秋末初冬的两个时间段，使用半连续热分析仪获得的数据。在夏季，EC与OC的相关性较差（r=0.46），OC/EC比值较高，而在秋末冬初，两种碳质气溶胶组分的相关性较高（r=0.94）。一致的OC和二次气体（NO2+O3）的峰值，观察在夏季发作，也在一些冬季发作的日子，这表明一个显着的非主要贡献OC在细气溶胶，与气态污染物的光化学氧化。OC分配之间的主要和次要来源已尝试使用EC示踪模型的两个测量期间。在夏季，这一分配的结果非常依赖于选定的线性回归的y轴截距值（被认为是非燃烧OC背景浓度）。在污染的日子里，二次贡献的OC分数的计算得到的昼夜最大小时估计值的范围从35%到55%，每天的估计值平均在10- 19小时期间从25%到45%。因此，这将证实每日城市的二次有机气溶胶的光化学起源，虽然生物的贡献，OC背景和SOA的形成可能是显着的，在该地区在夏季。在晚秋初冬事件的主要贡献OC更为普遍，虽然该模型还估计最大小时值的次级OC的顺序为35%的测得的OC。
An analysis of hourly measurements of gaseous pollutants and fine carbonaceous aerosol (PM2.5) divided into two fractions, elemental and organic carbon (EC and OC), in a suburban Madrid metropolitan area site is presented. Data were obtained using a semi-continuous thermal analyser for two periods of time during the summer and late autumn–early winter of 2003. In the summer period, correlation between EC and OC was poor (r=0.46), and high OC/EC ratios were usually found. In contrast, during the late autumn–early winter period the two carbonaceous aerosol fractions showed a high degree of correlation (r=0.94). Coincident peaks of OC and secondary gases (NO2+O3) were observed during summer episodes and also on some winter episodic days, suggesting a significant non-primary contribution to OC in fine aerosol, linked to photochemical oxidation of gaseous pollutants. OC apportionment between primary and secondary origins has been attempted for the two measuring periods using the EC tracer model. In the summer period, the results of this apportionment were very dependent on the y-intercept value (considered as the non-combustion OC background concentration) of selected linear regressions. Calculation of the secondary contribution to the OC fraction during polluted days gave diurnal maximum hourly estimations in a range from 35% to 55% and daily estimations averaged during the 10–19h period ranging from 25% to 45%. Thus, this would confirm a daily urban photochemical origin for the secondary organic aerosol, although biogenic contribution to both the OC background and the SOA formation may be significant in the area during summer. During late autumn–early winter episodes primary contribution to OC was more prevailing, although the model also estimated maximum hourly values of secondary OC in the order of 35% of the measured OC.