Characteristics And Source Apportionment Of Carbon Components In PM_2.5 In Autumn And Winter In Cities Of Fenhe Plain

Carbon is an important component of PM_2.5,which has important effects on aerosol radiative forcing,global warming,atmospheric visibility and human health,etc.It is of great significance to analyze its characteristics and sources.In this study.the carbonaceous components in PM_2.5 was analyzed using a heat/light analyzer.The sources apportionment of carbonaceous components in study area was performed via PMF and the Potential Source Contribution Function and Contribution-Weighted Trajectory model was used to analyze the potential sources area of the carbonaceous fraction.This study reveals the pollution characteristics and sources of carbonaceous components in the cities of the Fenhe Plain in terms of concentration characteristics,concentration difference in cities and sources apportionment,which provides data support and management thoughts for local management on PM_2.5 control.The main conclusions of this paper are as follows:（1）The concentrations of PM_2.5 were higher in Jinzhong city（82.1 μg/m³）and Yuncheng city（79.6 μ/m³）.The organic carbon（OC）concentration was higher in Yuncheng city（11.2 μg/m³）and Linfen city（11.0 μg/m³）,and the concentration of elemental carbon（EC）was higher in Jinzhong city（6.0 μg/m³）and Yuncheng city（4.7 μg/m³）.The highest concentration of secondary organic carbon（SOC）was found in Yuncheng city（3.0 μg/m³）,Sanmenxia city（2.5 μg/m³）and Linfen city（2.5 μg/m³）,but Sanmenxia city（40.3%）and Lvliang city（32.4%）had a higher proportion of SOC to OC.Correlation analysis showed the OC,EC and SOC concentration of the cities in the Fenhe plain were significantly positively correlated with the pollutants of SO₂,NO₂ and CO during the sampling period,indicating that Fenhe plain cities were greatly affected by the emissions of coal,industry and vehicles.（2）Results of source apportionment showed that coal combustion source（25.5%）contributed the most to carbon components in Fenhe Plain,followed by diesel vehicle exhaust（22.5%）,gasoline vehicle exhaust（22.3%）,dust source（18.3%）,and biomass combustion source（11.4%）contributed the least.Coal combustion source is the main contributor to the carbonaceous components in Fenhe Plain cities and are the key sources to be controlled in this area.In addition,the impact of motor vehicles on the carbonaceous components should be paid attention to,especially diesel vehicles.（3）The analysis of the backward trajectory concentration weights showed that the cities was mainly influenced by the airflow from the northwest direction,with the highest percentage of 75.3%,in addition to the local contribution,mainly by the long-range transmission from Mongolia and Xinjiang Uygur Autonomous Region through northern Gansu province,northern Ningxia province,central and western Inner Mongolia and northern Shaanxi province.OC in Fenhe Plain were located in the northwestern and southwestern parts of Fenhe Plain,southern Gansu Province,northern Shaanxi Province and north-central Henan Province during the sampling period in Fenhe Plain area,while OC also had local influence,mainly in the southeastern part of Lvliang City.There is a influence of EC in the southeastern part of Lvliang City,and its potential sources are mainly in the northwestern part of the Fenhe Plain,northern Shaanxi Province and Gansu Province.