Impact of VOCs emission from iron and steel industry on regional O3 and PM2.5 pollutions

Abstract

Iron and steel industry emission is an important industrial source of air pollution. However, little is known about the relationship between volatile organic compounds (VOCs) emitted and regional air pollution. In this study, VOCs emissions from a typical iron and steel plant in Yangtze River Delta (YRD, China) were monitored from April 2018 to March 2019. The ozone formation potential (OFP) and secondary organic aerosol (SOA) formation of VOCs were calculated to reveal the influence of VOCs emissions on regional ozone and particulate pollution, and the sensitivity analysis approach was performed to explore the qualitative and quantitative relationships between VOCs and O₃, as well as VOCs and PM_2.5. The VOCs concentration was 93.76 ± 266.97 ppbv during the study. The OFP was 760.08 ± 2391.90 μg m⁻³, and aromatics were the predominant precursors, contributing 54.05% of the total OFP. Furthermore, the SOA estimated by fractional aerosol coefficient (FAC) and time-resolved (TR) methods were 6.032 ± 13.347 μg m⁻³ and 0.971 ± 4.650 μg m⁻³, accounting for 8.65–26.39% (13.78 ± 7.46%) and 1.55–4.20% (2.22 ± 1.23%) of the PM_2.5 concentrations, respectively. The results indicated that VOCs were more sensitive to O₃ pollution in high pollution domains, whereas VOCs were more sensitive to PM_2.5 pollution in low pollution domains. We concluded that reducing VOCs emissions might be effective in alleviating photochemical pollution episodes in areas around iron and steel industry, and the haze pollution occurred in these regions may be caused by the primary emission of PM, and the contribution of SOA was relatively small.