沈阳一次雾霾天气颗粒物浓度及光学特征变化

利用2011年10月17~22日连续在线观测沈阳地区大气能见度、颗粒物质量浓度ρ(PM10)、ρ(PM2.5)、ρ(PM1.0)、以及通过太阳光度计测量数据反演得到的气溶胶光学厚度、Angstrom波长指数、气溶胶粒子谱分布数据,结合相对湿度、风速、温度等气象资料,分析了2011年秋季沈阳一次雾霾天气过程中能见度与颗粒物质量浓度及气溶胶光学特征变化.结果表明:相对温度偏高、小风天气以及颗粒物质量浓度累积是造成沈阳能见度下降、引发雾霾天气的主要因素;雾霾期间细粒子所占比例较高,ρ(PM10)、ρ(PM2.5)、ρ(PM1.0)平均值分别为138.8、103.3、94.9μg/m3,比雾霾过程前均增加约2倍左右,PM2.5/PM10和PM1.0/PM10分别为74.7%和68.6%;当RH80%时,能见度与颗粒物质量浓度相关性显著(R20.90),RH80%时,能见度与颗粒物浓度间的相关性减弱;雾霾期间气溶胶光学厚度明显增加,雾霾前气溶胶光学厚度和Angstrom波长指数平均值分别为0.82和0.94,雾霾期间气溶胶光学厚度和Angstrom波长指数平均值分别为1.42和1.25;雾霾天气过程中,细模态粒子的峰值浓度约是雾霾前细粒子浓度的2倍,说明沈阳地区大气污染物以细粒子为主,进而影响气溶胶光学特征发生变化.

Characteristics of particle mass concentrations and aerosol optical properties during a fog-haze event in Shenyang

Data of visibility, particulate mass concentration (PM10、PM2.5、PM1.0) and the aerosol optical properties retrieved by CE318sun-photometer were analyzed together with surface meteorological elements (relative humidity, wind speed, temperature) during a fog-haze event in Shenyang, China, from October 2011 17 to 22. The results indicated that the higher relative temperature and the lower wind speed as well as the accumulation of mass concentrations are the main factors resulting the poor visibility and the fog-haze weather. The mass concentration of ρ(PM10)、ρ(PM2.5)、ρ(PM1.0) are about 138.8μg/m3, 103.3μg/m3, 94.9μg/m3, respectively, which were 2 times higher than those on non fog-haze days. The average ratio of PM2.5/PM10 and PM1.0/PM10 were about 74.7% and 68.6%, respectively. There is a strong correlation (R2>0.90) between visibility and PM mass concentration when the relative humidity was lower than 80%. However, the correlation was decreased when the relative humidity was higher than 80%. The AOD500nm and Angstrom exponent on fog-haze days were higher than those on non fog-haze conditions. The values of AOD at 500 nm and Angstrom exponent on non fog-haze days are about 0.82 and 0.94 while during the haze-fog episodes, these two parameters increased to 1.42 and 1.25, respectively. The aerosol size distribution comes from the addition of fine aerosol particles on haze day were 2 times higher than those on non-haze days which indicating the predominance of fine particles on fog-haze days to further affect the aerosol optical characteristics.