2017年佛山市大气复合污染特征及来源分析

Characteristics and Source Analysis of Composite Air Pollution in Foshan City in 2017

利用2017年佛山市8个国控监测点位的6项常规大气污染物自动监测数据,研究细颗粒物(PM_(2.5))、可吸入颗粒物(PM 10)、臭氧(O_(3))的时空变化和复合污染特征,并采用单颗粒气溶胶质谱仪对佛山市大气PM_(2.5)进行来源解析,分析O_(3)与二次气溶胶的协同增长关系。结果表明,2017年佛山市空气质量综合指数(AQI)为4.75,主要的空气质量污染物为PM_(2.5)、二氧化氮(NO_(2))和O_(3),除O_(3)呈现第2,3季度较高外,其他5项污染物均呈现第1,4季度较高的趋势。ρ(PM_(2.5))和ρ(PM_(2.5))/ρ(CO)在1—4月和11,12月较高,二次生成强度较大。机动车尾气源、燃煤源和工业工艺源是大气PM_(2.5)的主要来源。佛山市中心城区等道路密集以及交通枢纽地区的ρ(NO_(2))较高,机动车尾气排放是大气NO_(2)的主要来源。O_(3)污染主要发生在4,5,7—10月。ρ(O_(3))和ρ(PM_(2.5))/ρ(CO)的日变化均在12:00—17:00达到峰值。ρ(PM_(2.5))随光化学活性水平增强而提高,高度和中度光化学活性水平下ρ(PM_(2.5))/ρ(CO)明显大于轻度和低光化学活性水平。在统计时段,PM_(2.5)和O_(3)协同增长的时间占37.3%,O_(3)污染对二次气溶胶的氧化生成有明显的促进作用。

Using automatic monitoring data of the national monitoring network of 6 conventional atmospheric pollutants in Foshan in 2017,the spatial and temporal variation and combined pollution characteristics of PM_(2.5),PM 10 and O_(3)were studied.Moreover on-line source apportionment of PM_(2.5)in Foshan was carried out using a single particle aerosol mass spectrometer.The synergistic relationship between O_(3)and secondary aerosols was analyzed.The results demonstrated that the comprehensive air quality index(AQI)of Foshan in 2017 was 4.75.PM_(2.5),NO_(2)and O_(3)were primary pollutants.Except the concentration of O_(3)was higher in the second and third quarters,the other 5 pollutants showed a higher trend in the first and the last quarters.The concentration ofρ(PM_(2.5))andρ(PM_(2.5))/ρ(CO)was higher in January to April and November to December,and the concentration of secondary PM_(2.5)was higher.Vehicle,coal-burning and industrial process were the primary sources of PM_(2.5).The concentration of NO_(2)was highest in the areas with dense roads and transportation hubs in the central district of Foshan.Vehicle was the main source of NO_(2).O_(3)pollution occurred most frequently in April,May and July to October.ρ(O_(3))andρ(PM_(2.5))/ρ(CO)reached a peak around 12:00 to 17:00.With the enhancement of photochemical activity,concentrations ofρ(PM_(2.5))increased.The ratio ofρ(PM_(2.5))/ρ(CO)at high and moderate photochemical activity was significantly greater than that at a mild and low photochemical activity.The synergistic growth period of PM_(2.5)and O_(3)accounted for 37.3%in the statistical period,and the synergistic growth effects of O_(3)on secondary aerosol formation were significant.