Characteristics of VOCs and Ozone Formation Sensitivity during Typical Pollution Days in Xuchang
To mitigate air pollution,prevent and control air pollution in a scientific and systematic manner,and promote the continuous improvement of regional ambient air quality,real time monitoring of Volatile Organic Compounds(VOCs)in Xuchang was conducted during three defined periods:pre-pollution,during-pollution,and post-pollution.The pollution characteristics of VOCs and the ozone formation patterns were studied based on the obtained data.The results showed that the average concentrations of VOCs in the pre-pollution,during-pollution and post-pollution periods were 33.5×10-9,39.9×10-9 and 28.7×10-9,respectively.The dominant component was Oxygenated Volatile Organic Compounds(OVOCs),followed by alkanes.The con-centrations of acetaldehyde,propionaldehyde,and acetone during the pollution period were significantly high-er than those during the non-pollution periods.During the pollution period,the Ozone Formation Potential(OFP)was 313.72 μg/m3,which was 1.4 and 1.6 times of that in the pre-pollution and post-pollution peri-ods,respectively.This indicated that the potential for ozone formation through photochemical reactions of VOCs increased significantly during the ozone pollution period in Xuchang.The Relative Incremental Reactiv-ity(R1R)indicated that Xuchang was in the limited regime of VOCs during the post-pollution period,while it was in the transition regime in the pre-pollution and during-pollution periods.The source apportionment of anthropogenic VOCs by the Positive Matrix Factorization(PMF)model showed that industrial and combus-tion sources contributed 54.4％to VOCs during the study period.The contributions of industrial sources during the pollution period increased by 5.1％and 5.5％compared with those in the pre-and post-pollution periods,respectively,while the contributions of combustion sources increased by 8.8％and 8.7％,respective-ly.These findings indicated that industrial and combustion sources were key contributors to elevated concen-trations of VOCs during the pollution period.The Potential Source Contribution Function(PSCF)and Con-centration Weighted Trajectory(CWT)revealed that cities in eastern and northwestern Henan Province ex-erted an intensified impact on the concentration of VOCs in Xuchang during the pollution period.
万方数据
维普
