Non-methane hydrocarbon characteristics and their ozone and secondary organic aerosol formation potentials and sources in the plate and logistics capital of China

Abstract

Non-methane hydrocarbon (NMHC) is an important precursor of ozone (O3) and secondary organic aerosols (SOAs). As the plate and logistics capital of China, the characteristics and sources of NMHC in Linyi may differ from other areas. Therefore, to understand NMHC pollution characteristics and guide future control strategies, samples were collected from April to October 2021–2022 in Linyi to analysis NMHC concentration levels, ozone formation potential (OFP), secondary organic aerosol formation potential (SOAFP), and sources in different seasons. The NMHC concentrations in spring and summer were 100.1 ± 29.5 and 98.4 ± 31.7 μg/m3, respectively, higher than in autumn (83.7 ± 25.1 μg/m3) due to the re-outbreak of COVID-19 in Linyi in autumn. However, no difference was seen in the dominant NMHC contributors—oxygenated volatile organic compounds (OVOCs), alkane, and aromatics—among different seasons. Both the OFP and SOAFP of NMHC showed obvious seasonal variations with summer > spring > autumn. Promoting the use of non-formaldehyde adhesive and reducing 1, 3-diethylbenzene in organic synthesis are crucial for alleviating O3 and SOA pollution, respectively. Vehicle related, liquefied petroleum gas (LPG), natural gas (NG), solvent use, and the plate industry were the main NMHC sources in Linyi. The contribution of vehicle related and LPG/NG in autumn (13.7%) was lower than in spring (32.7%) and summer (29.4%), while the contribution of combustion in summer (5.7%) was lower than in spring (15.6%) and autumn (17.9%), consistent with the results of species-specific diagnostic ratios. Regional pollution transport was also analyzed. Although we encourage joint prevention and control regarding air pollution, the main areas of joint prevention and control should be different in different seasons, which can reduce adverse human effects and the consumption of material and financial resources.