Identifying hotspots based on high-resolution emission inventory of volatile organic compounds: A case study in China

The emission of volatile organic compounds (VOCs) makes a substantial contribution in the formation of secondary organic aerosols (SOAs) and ground-level ozone, which could deteriorate air quality and cause damage to human health. To help inform local VOCs management decisions, we compiled a speciated and high spatial resolution anthropogenic VOCs emission inventory for Huai'an City in 2017, using investigated human activity data and the latest emission factors. Furthermore, the ozone formation potential (OFP) was estimated to understand the contributions of different VOC species to ozone formation. The results show that Huai'an City emitted about 36 kt of VOCs in 2017, mainly from industrial processes, e.g. petroleum refining and iron & steel industry, and solvent use, e.g. pesticide use and asphalt paving, accounting for 41% and 32% of the total emissions, respectively. The high emissions were spatially located in the areas where there is an intensive cluster of industrial enterprises, with the top 20 VOCs emitting enterprises contributing to 43% of the city's total. These anthropogenic VOCs emissions, especially m/p-xylene, ethylene, propene, toluene, have the potential to form about 102 kt ozone in the lower atmosphere. Different from the hotspots identified based on physical weights, solvent use became the largest constituent and m/p-xylene was the leading VOC species. By investigating the spatial distribution of anthropogenic VOCs emissions and the OFP, this work highlights the necessity to consider VOC species and different effects they might have on ozone formation in future hotpot identification, which could lay a more scientific basis for local VOCs emission mitigation strategies.