摘要
采用观测数据与轨迹模拟相结合的方法,综合分析了2015年3月26日-4月1日北京市一次沙尘天气过程中沙尘输送路径、天气形势、污染物浓度的变化特征,结果发现:此次外来沙尘路径为西北路径,沙尘源地位于蒙古国南部的戈壁地区;沙尘在冷空气和地面低压系统作用下快速移动,造成延庆、奥体中心、永乐店3站点PM_(10)2 h左右浓度维持1 000μg/m^3,能见度低于1 km,空气质量急剧恶化;沙尘过境时PM_(10)浓度明显上升,PM_(2.5)浓度受到的影响相对较小,SO_2、NO_2、CO浓度变化不明显;沙尘回流时携带区域污染物进入北京,各项污染物及颗粒物组分浓度出现一定程度的上升;受沙尘影响,Mg^(2+)、Ca^(2+)、Na^+浓度明显上升,峰值浓度分别为0.13、1.29、0.70μg/m^3,分别是年均浓度的1.86倍、2.80倍、2.06倍;沙尘天气过后,扩散条件转差,沙尘与污染天气相继共造成北京市空气质量连续4 d维持中度污染级别。
A dust weather process from 26 th March to 1st April in Beijing in 2015 was investigated by using observed data and the numerical model HYSPLIT. Analysis results showed that source of this alien dust was located in the south of Mongolia＇s Gobi area and its transportation path was northwest paths compared to other dusts;the sand moved quickly by the cold air and ground low pressure which caused the concentrations of PM（10） at sites of Yanqing,Olympic Sports Center,Yongledian increased to 1 000 μg/m^3 that lasted about two or three hours,with the visibility in Beijing less than 1 000 m and air quality sharply deteriorated. When the sand dust storm passed Beijing,concentration of PM（10） increased significantly,PM2.5 relatively smaller while concentration of SO2,NO2,CO concentration did not change significantly. Pushed by the Bohai weak high pressure system,the sand dust carrying anthropogenic pollutants flew back to Beijing and led the concentrations of various pollutants and chemical compositions increased to a certain extent,with the peak concentrations of Mg^2＋,Ca^2＋,Na~＋ as 0.13,1.29,0.70 μg/m^3 respectively which was 1.86,2.80,2.06 times of the annual average concentrations during sand dust storms. After the dust weather,the diffusion condition deteriorated;the dust weather and later air pollution had caused the air quality in Beijing moderate pollution level maintaining for four days.
出处
《环境科学与技术》
CAS
CSCD
北大核心
2016年第4期137-143,160,共8页
Environmental Science & Technology
基金
国家科技支撑计划(2014BAC23B02)
环境保护公益性行业科研专项(201409005,2014001019)
北京市环境保护科学研究院科技基金(2014-A-03)
作者简介
李珊珊（1983-），女，高级工程师，博士，主要从事大气环境及资源环境遥感研究，（电子信箱）liss0502@163．com；
通讯作者，女，高级工程师，主要从事大气污染防治方面的研究，（电子信箱）yanjing@cee．cn。
