Abstract:In order to study the characteristics of volatile organic compounds (VOCs) in Yantai city, VOCs chemical composition, concentration characteristics, ozone generation potential (OFP) and pollutant sources were analyzed based on VOCs monitoring data in Yantai in 2020 and 2022. Results indicated that the volume concentration of VOCs showed a decreasing trend (-12.4%) from 2020 to 2022, which was attributed to the significant decrease in the concentration of oxygen-containing volatile organic compounds (OVOCs) (decreased by -33.1%) with a stable concentration of ozone precursors (PAMS). Species concentration analysis showed that alkanes and aldehydes ranked first in the volume concentration of PAMS and OVOCs. The three components with the highest volume concentration were formaldehyde, ethane and propane, and the three components with the highest mass concentration were n-hexane, formaldehyde and propane, respectively. Time distribution characteristics displayed that the volume concentration of PAMS and OVOCs fluctuates greatly, and high concentrations were prone to appear in July and August. Total OFP value of Yantai City also showed a downward trend, decreasing by 14.0% compared with 2020, among which the OFP value of various types of VOCs was as follows: aldehydes > alkenes > alkanes > aromatics > ketones > alkynes, and the top three contribution values accounted for 88.2%. According to the calculated value of OFP, formaldehyde and acetaldehyde had always been the top two contributors to the generation of O3 in the ambient air in Yantai city, and the ozone prevention and control in Yantai city should focus on the following five components: formaldehyde, acetaldehyde, 2-methyl-1, 3-butadiene, ethylene and propylene. Source analysis results showed that the VOCs in Yantai city came from aging air mass transport, in which formaldehyde and acetaldehyde were mainly from motor vehicle exhaust and man-made sources. Aromatic hydrocarbons were mainly derived from vehicle exhaust and coal/biomass interaction, in which motor vehicles had a more significant impact. This study provided a scientific basis in formulating measures for the prevention and control of VOCs emissions and O3 pollution. It is suggested that Yantai City should conduct accurate control on anthropogenic emissions (especially motor vehicles) and coal/biomass by combining VOCs concentration characteristics, species characteristics, time distribution characteristics and chemical reactivity analysis, so as to improve the ambient air quality of Yantai City.