Full-Volatility Reactive Organic Carbon Emissions from Volatile Chemical Products in Mainland China

Abstract

Volatile chemical products (VCPs), including personal care products, general cleaners, architectural coatings, pesticides, adhesives, and others, are becoming increasingly significant anthropogenic sources of reactive organic carbon (ROC) in China. These ROC serve as critical precursors to ozone (O₃) and secondary organic aerosols (SOAs). Therefore, it is essential to estimate ROC emissions from VCPs in China accurately. In this study, the VCPy framework developed by the U.S. EPA was used to simulate ROC evaporative emissions from VCPs in mainland China, and its emission inventory was established. The results indicate that in 2019, the total ROC emissions from VCP sources in mainland China amounted to 9.4 Tg (6.9 TgC) with a 95% confidence interval of 8.4–11.8 Tg (6.2–8.7 TgC). The category of paints and coatings emerged as the dominant contributor to ROC emissions, emitting 6.0 Tg (4.4 TgC), accounting for 63.7% of total ROC emissions, followed by the category of cleaning products at 11.2% and the category of adhesives at 10.1%. Among ROC emissions, volatile organic compounds (VOCs) accounted for the largest proportion, followed by intermediate-volatility organic compounds (IVOCs), accounting for 23.6%. Oxygenated organic compounds and aromatics were the dominant components emitted from VCPs, accounting for 48.0% and 31.0% of ROC emission mass, respectively. Moreover, the mass proportion of oxygenated organic compounds in IVOC emissions was 72.0%. However, oxygenated organic compounds and aromatics were still predominantly emitted in the form of VOCs. Additionally, the O₃ formation potential (OFP) and SOA formation potential (SOAFP) of the ROC emissions from VCPs were estimated at 32.0 and 0.5 Tg, respectively, suggesting the significant impact of ROC emissions on O₃ and SOA from VCP sources. Emissions of oxygenated organic compounds contributed significantly to OFP and SOAFP by 33.8% and 17.1%, respectively. By comparing with measurement data, the VCPy framework can reliably reproduce the emissions of key species from VCPs in mainland China. This study provides essential basic data for a more comprehensive assessment of the impact of VCP emissions on SOA and ozone in mainland China.