Liu Zi-Rui, Wang Yue-Si, Liu Quan, Liu Lu-Ning, Zhang De-Qiang
LAPC, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China.
Huan Jing Ke Xue. 2011 Nov;32(11):3160-6.
Real-time measurements of PM2.5, secondary inorganic compounds in PM2.5 (SO4(2-), NH4(+), and NO3(-)) and related gaseous pollutants were conducted at Mount Dinghu, a regional background station of the Pearl River Delta (PRD), in October and November 2008 by using a conventional R&P TEOM and a system of rapid collection of fine particles and ion chromatography (RCFP-IC). Sources and transportation of atmospheric particles during the experiment were discussed with principal component analysis and backward trajectories calculated using HYSPLIT model. The average daily mass concentrations of PM2.5 were 76.9 microg x m(-3) during sampling period, and average daily mass concentrations of SO4(2-), NH4(+), and NO3(-) were 20.0 microg x m(-3), 6.8 microg x m(-3) and 2.6 microg x m(-3), respectively. The sum of these three secondary inorganic compounds accounted for more than one third of the PM2.5 mass concentration, which had become the major source of atmospheric fine particles at Mount Dinghu. The diurnal variation of PM2.5, SO4(2-), and NH4(+) all showed a "bimodal" distribution with two peaks appeared at 10:00 am and at 16:00 pm, respectively, whereas NO3(-s) howed "single peak" distribution peaked at 10:00 am. The mass concentrations of SO4(2-) in PM2.5 had the similar diurnal variation with that of SO2, SO4(2-) in PM2.5 was mainly transformed from SO2, whereas NO3(-) showed difference diurnal variation with that of NO2, and the second conversion rate of NO2 was far lower than that of SO2. NH4(+) in PM2.5 existed mainly in the form of sulfate, nitrate and chloride. Both of principal component analysis and back trajectory analysis showed that the variations of PM2.5 and secondary inorganic compounds at Mount Dinghu were mainly affected by the long-range transport air mass passed over Guangzhou, Huizhou and other highly industrialized areas which carried air pollutants to the observation site, at the same time local sulfate originated from secondary formation also contributed an important part of atmospheric fine particles and the contribution from local direct emission was little.
2008年10月和11月，在珠江三角洲地区背景站鼎湖山，使用传统的R&P TEOM以及细颗粒快速采集与离子色谱系统（RCFP-IC）对PM2.5、PM2.5中的二次无机化合物（SO4(2-)、NH4(+)和NO3(-)）及相关气态污染物进行了实时测量。利用主成分分析和使用HYSPLIT模型计算的后向轨迹，讨论了实验期间大气颗粒物的来源和传输。采样期间PM2.5的日均质量浓度为76.9μg x m(-3)，SO4(2-)、NH4(+)和NO3(-)的日均质量浓度分别为20.0μg x m(-3)、6.8μg x m(-3)和2.6μg x m(-3)。这三种二次无机化合物的总和占PM2.5质量浓度的三分之一以上，已成为鼎湖山大气细颗粒物的主要来源。PM2.5、SO4(2-)和NH4(+)的日变化均呈“双峰”分布，两个峰值分别出现在上午10:00和下午16:00，而NO3(-)呈“单峰”分布，峰值出现在上午10:00。PM2.5中SO4(2-)的质量浓度与SO2具有相似的日变化，PM2.5中的SO4(2-)主要由SO2转化而来，而NO3(-)与NO2的日变化不同，NO2的二次转化率远低于SO2。PM2.5中的NH4(+)主要以硫酸盐、硝酸盐和氯化物的形式存在。主成分分析和后向轨迹分析均表明，鼎湖山PM2.5和二次无机化合物的变化主要受经过广州、惠州等高度工业化地区的长距离传输气团影响，这些气团将空气污染物输送到观测站点，同时本地二次生成的硫酸盐也是大气细颗粒物的重要组成部分，本地直接排放的贡献较小。
