[Characteristics and Source Apportionment of Volatile Organic Compounds in the Rainy Season of Guangzhou City]

Atmospheric volatile organic compounds (VOCs) were measured in an urban area of Guangzhou on July 2016 using an on-line gas chromatography mass spectrometry/fire ion detector. Seventy-three VOCs were detected with an average concentration of (118.83±79.40) μg·m^-3, a maximum concentration of 492.42 μg·m^-3, and a minimum concentration of 10.54 μg·m^-3 during the period. The peak value of the TVOC concentration appeared at about 07:00 in the morning, indicating that motor vehicle pollution had a significant contribution at the site. The minimum value appeared at about 14:00 in the afternoon, related to photochemical losses. High concentrations were also observed from 21:00 to 24:00, which was probably related to pollution emissions and boundary layer compression. Source analysis by PMF showed that the site was mainly affected by five VOC sources: vehicle exhaust, solvent use, fuel loss at fuel stations, plant emissions, and cooking exhaust, the contributions of which were 29.79%, 26.61%, 24.86%, 9.91%, and 8.84%, respectively. Vehicle exhaust was the largest source of VOCs during the daytime, while the contribution of plant emissions increased significantly at noon. The contribution of solvent uses and fuel loss at fuel stations rose during the night and became the main source of VOCs until early morning.