西安西南郊“夏防期”大气VOCs污染特征及来源解析

Analysis of atmospheric VOCS pollution characteristics and sources in the southwest suburbs of Xi'an during the"summer prevention period"

于2021年8月1日—9月30日开展“夏防期”西安西南郊大气挥发性有机物(VOCs)污染监测,累计监测到不同大气VOCs组分70种.基于监测结果梳理分析西安西南郊大气VOCs污染分布特征及进行臭氧生成潜势(OFP)评估,并运用PMF模型解析VOCs主要来源.结果表明:①监测期间西安西南郊平均TVOCs浓度为181.89μg·m^(-3),工业园区污染物浓度(189.32μg·m^(-3))整体略高于城区(164.96μg·m^(-3)),以甲醛和乙醛为主的醛酮类物质占比最高(88.10%),醛酮类物质浓度下午时段高于上午时段.②OFP评估结果表明,醛酮类物质对西安西南郊臭氧生成贡献较大,其中,甲醛、乙醛和丙醛是对该区域近地面O_(3)生成贡献最大的3种物质.③PMF源解析结果显示,西安西南郊大气VOCs主要来源依次为移动源、油气挥发源、溶剂涂料源、工业过程源,其中,以工业企业生产排放为主的溶剂涂料源与工业过程源均指向工业园区,表明当前西安西南郊大气VOCs来源以机动车尾气排放和工业园区企业生产排放为主.

The monitoring of atmospheric VOCs pollution in the southwest suburbs of Xi'an during the"summer prevention period"was carried out from 2021-08-01 to 2021-09-30.70 different types of VOCs components in the atmosphere were monitored totally.Based on the monitoring results,the characteristics of atmospheric VOCs Pollution’s distribution and the evaluation of the generation of ozone potential in the southwest suburb of Xi'an were analyzed,and then the main source of VOCs using the PMF model was utilized.The results show that the averaged TVOCs concentration in the southwest suburb of Xi'an was 181.89μg·m^(-3)during the monitoring period.The concentration of pollutants in industrial parks(189.32μg·m^(-3))was slightly higher than that in urban areas(164.96μg·m^(-3))overall.The highest proportion are ketones and aldehydes with formaldehyde and acetaldehyde(88.10%),and the concentration of ketones and aldehydes is higher in the afternoon than that in the morning.The OFP assessments show that the formation of ketones and aldehydes have contributed more to the ozone in the southwestern suburbs of Xi'an.Among them,formaldehyde,acetaldehyde,and propane are the three substances with the largest contribution to O_(3)near the ground of the area.PMF source analysis results show that the main sources of atmospheric VOCs in the southwestern suburbs of Xi'an are mobile sources,volatiles of oil and gas,sources of solvents and coatings,and sources of industrial process.The sources of solvents and coatings and the sources of industrial processes which are mainly produced by industrial enterprises pointed to the industrial park.The current sources of VOCs from the southwestern suburbs of Xi'an are mainly based on vehicle emissions and enterprises from industrial parks.