不同天气类型广东大气超级站细粒子污染特征初步研究

摘要

2012年5月至7月期间,以广东大气超级监测站为观测平台,利用单颗粒气溶胶质谱仪(SPAMS)和其他多种环境监测仪器对大气污染现象进行高时间分辨的长期连续观测。以能见度和相对湿度为参考,将天气类型划分为2次灰霾、1次暴雨和多次晴朗天气过程。观测结果表明, SPAMS捕获的颗粒物数浓度与PM2.5和PM1的相关性(R2)分别达到0.538和0.448,呈现出一定的相关性。大气颗粒物浓度在不同天气条件下,浓度变化较大,其中,灰霾天气下, PM2.5和PM1浓度最大小时均值分别达到0.132 ng/m3和0.094 ng/m3。观测结果表明,粒径处于600~800 nm的细颗粒物对该区域的灰霾形成过程起了最为关键的作用。该地区的大气颗粒物类型主要可分为7种：元素碳(EC)、有机碳(OC)、元素-有机碳混合(ECOC)、大分子有机碳(HMOC)、海盐(Na-K)、富钾颗粒(K-rich)和富铅颗粒(Pb-rich)。灰霾天气,各类型颗粒物数量浓度均有一定程度的增加,其中以EC和K-rich的增加最为明显。分析表明,第一次灰霾主要是由于大气光化学反应起到主导作用,而生物质燃烧又增大了灰霾程度；第二次灰霾过程,生物质燃烧产生的影响更大。%Environment monitoring was conducted on atmospheric pollution at Guangdong supersite, using single particle aerosol mass spectrometry (SPAMS) and a variety of environmental monitoring equipment, with high-time resolution during May to July, 2012. According to the record of visibility and relative humidity, the sampling period was divided into two haze, one heavy rain and one sunny episodes. It showed that the correlations (R2) were 0.54 and 0.45 between the obtained SPAMS particle number and PM2.5 and PM1, respectively. Atmospheric pollutant concentration changed with weather conditions. Maximum average hour concentration of PM2.5 and PM1 could reached 0.132 and 0.094 ng/m3 during haze, respectively. SPAMS size distribution information indicates that 600-800 nm of fine particulate matter plays a key role to the haze. Atmospheric particulates can be mainly divided into seven types, including elemental carbon (EC) and organic carbon (OC), mixtures of element-carbon (ECOC), high mass organic carbon (HMOC), sea salt (Na, K), potassium rich (K-rich) and lead rich (Pb-rich) particles. Particle number concentration of each particle type had a certain degree of increase in haze, in particular, EC and K-rich. The result showed that the atmospheric photochemical reactions played a leading role for the first haze; meanwhile, biomass burning increased the degree to some extent. The biomass combustion had a greater impact on the secondary haze.