Significant contributions of the petroleum industry to volatile organic compounds and ozone pollution: Insights from year-long observations in the Yellow River Delta

Abstract

The petroleum industry is a significant source of anthropogenic volatile organic compounds (VOCs), but up to now, its exact impact on urban VOCs and ozone (O3) remains unclear. This study conducted year-long VOC observations in Dongying, China, a petroleum industrial region. The VOCs from the petroleum industry (oil and gas volatilization and petrochemical production) were identified by employing the positive matrix factorization model, and their contribution to O3 formation was quantitatively evaluated using an observation-based chemical box model. The observed annual average concentration of VOCs was 68.6 ± 63.5 ppbv, with a maximum daily average of 335.3 ppbv. The petroleum industry accounted for 66.5% of total VOCs, contributing 54.9% from oil and gas evaporation and 11.6% from petrochemical production. Model results indicated that VOCs from the petroleum industry contributed to 31% of net O3 production, with 21.3% and 34.2% contributions to HO2+NO and RO2+NO pathways, respectively. The larger impact on the RO2 pathway is primarily due to the fact that OH+VOCs account for 86.9% of the primary source of RO2. This study highlights the critical role of controlling VOCs from the petroleum industry in urban O3 pollution, especially those from previously overlooked low-reactivity alkanes.