Pollution Characteristics and Source Apportionment of Volatile Organic Compounds (VOCs) in the Main Urban Area of Wuxi City, 2025

Abstract

In To identify pollution sources of volatile organic compounds (VOCs) in Wuxi City, we analyzed their pollution characteristics, ozone formation potential (OFP) and source apportionment using online monitoring data from December 2024 to November 2025. The average VOCs volume fraction was 38.90×10-9, showing a seasonal trend of higher levels in winter/autumn and lower in spring/summer. Alkanes (30.90%) and oxygenated VOCs (OVOCs, 34.71%) were the dominant components, and all chemical species exhibited a "double peaks and one valley" diurnal pattern.Total OFP reached 75.90 μg/m³, with OVOCs (55.87–66.16%) being the primary contributor across seasons. Aromatic hydrocarbons contributed significantly more in winter (15.71%) than in spring, summer and autumn (4.93–8.79%). Acetaldehyde (19.43–32.02%) ranked first in annual OFP contribution, followed by acrolein and vinyl acetate. Positive Matrix Factorization (PMF) identified seven source factors. Motor vehicles (28.6%) and solvent usage (19.9%) were the dominant VOCs sources, followed by plant/biomass combustion (12%), combustion sources (10.7%), industrial emissions (10.6%), LPG (9.9%) and oil/gas volatilization (8.2%). Therefore, priority should be given to controlling these two major sources for effective VOCs abatement in Wuxi.