郑州市两次典型大气重污染过程成因分析

于2017年11月21~29日利用在线金属分析仪及气象仪器在郑州大学站点进行连续观测，识别郑州市秋冬季节典型灰霾重污染爆发的成因.结果表明：观测期间采样点大气PM_2.5中As，Mn，Fe，Cu和Zn等元素浓度相比其他城市较高；基于气象数据统计分析可知，来自郑州市东北方向污染气团的传输，以及低风速、高湿度的静稳天气造成的本地排放污染物积聚是这两次重污染形成的主要气象因素；同时，利用正矩阵因子分解法（PMF）定量解析出观测期间主要贡献源：扬尘源（36.8%），机动车源（27.6%），工业源（21.0%）和燃烧源（14.6%）.其中，扬尘源在清洁天的贡献占比较高，而重污染期间机动车源和燃烧源的贡献显著增大.

Analysis of the formation of two typical atmospheric heavy pollution episodes in Zhengzhou,China

To investigate the formation mechanism of heavy haze in fall and winter season of Zhengzhou, online measurements of hourly concentrations of elements in PM_2.5 using the ambient metals analyzer and meteorological instrument were conducted from Nov. 21^th to 29^that an urban site of Zhengzhou University. Results show that the concentrations of As, Mn, Fe, Cu, and Zn in Zhengzhou during the sampling periods were higher than in other cities. The polluted air mass transported from northeastern regions of Zhengzhou, and the lower wind speed, higher relative humidity and calm conditions which accumulating local pollutant emissions, based on the statistical analysis of meteorological data, were the major meteorological parameters causing the two heavy haze episodes. Meanwhile, quantitative source apportionment from the positive matrix factorization (PMF) model showed that dust, vehicle, industrial emission and combustion were the major sources of elements in PM_2.5, which accounting for 36.8%, 27.6%, 21.0% and 14.6%, respectively. The contribution of dust source in cleaning day was relatively higher and that of motor vehicle and combustion source increased significantly during heavy haze period.