2015—2018年乌鲁木齐市PM2.5及PM10时空分布特征

乌鲁木齐市是“丝绸之路经济带”关键节点城市，为了解乌鲁木齐市2015—2018年空气污染状况，利用2015年1月1日—2018年12月23日乌鲁木齐市7个国控空气质量监测站的ρ（PM_2.5）、ρ（PM₁₀）监测数据，基于ArcGIS空间分析平台，分析乌鲁木齐市PM_2.5、PM₁₀的时空分布特征.结果表明:ρ（PM_2.5）从2015年（66.60 μg/m3）到2016年（76.93 μg/m3）呈上升趋势，在2016—2018年呈单一下降趋势；ρ（PM₁₀）从2015年（132.74 μg/m3）到2016年（125.93 μg/m3）呈下降趋势，在2016—2018年呈单一上升趋势.2015—2018年工业活动集中的乌鲁木齐市边缘各区的ρ（PM_2.5）、ρ（PM₁₀）平均值比城市中心（商业区、居民区）分别高11.28、7.17 μg/m3，说明工业集中地区的大气环境质量受污染影响明显.此外，2015—2018年乌鲁木齐市大气污染呈季节性和北高南低的区域性分布特征.气象因子分析表明，ρ（PM_2.5）、ρ（PM₁₀）均与相对湿度呈正相关，与降雨量、风速等气象因素呈负相关.2015—2018年，乌鲁木齐市大气中ρ（PM_2.5）/ρ（PM₁₀）呈先增后降的趋势，冬季以PM_2.5污染为主，其他季节以PM₁₀污染为主.研究显示，2015—2018年乌鲁木齐市空气污染状况变化与地形、气象条件、城市化建设均有一定的关系. 

Spatial and Temporal Characteristics of PM2.5 and PM10 in Urumqi City from 2015 to 2018

Urumqi City is an important part of the 'Silk Road Economic Belt'. In order to understand the air pollution status in Urumqi City, we investigated spatial and temporal characteristics of PM_2.5 and PM₁₀ using real time monitoring data collected from seven air quality monitoring stations during January 1st, 2015 to December 23rd, 2018. We found that the annual average values of ρ(PM_2.5) increased from 66.60 μg/m3 in 2015 to 76.93 μg/m3 in 2016 and then decreased until 2018. However, the annual average ρ(PM₁₀) decreased from 132.74 μg/m3 in 2015 to 125.93 μg/m3 in 2016 and then increased until 2018. The annual average ρ(PM_2.5) and ρ(PM₁₀) in the fringe area of Urumqi City (where industrial activities are concentrated) were 11.28 and 7.17 μg/m3 higher than those in the central districts of the city (commercial and residential), indicating that the industrial activities had a significant impact on air quality. The spatial characteristics of ρ(PM_2.5) and ρ(PM₁₀) also showed a decreasing trend from the south to the north of the city. In addition, monthly average ρ(PM_2.5) and ρ(PM₁₀) were positively correlated with monthly average relative humidity and negatively correlated with rainfall and wind speed. From 2015 to 2018, ρ(PM_2.5) and ρ(PM₁₀) increased firstly and then decreased. Fine and coarse particles were the main pollutants in winter and other seasons, respectively. The results showed that the variations of air pollution in Urumqi City from 2015 to 2018 were mainly related to topography, meteorological conditions and urbanization.