Diffusion simulation, health risks, ozone and secondary organic aerosol formation potential of gaseous pollutants from rural comprehensive waste treatment plant

Abstract

Comprehensive waste treatment plants (CWTPs) are significant sources of gaseous pollutants such as odors, volatile organic compounds (VOCs) and nitrogen oxides (NOx), polluting the environment and endangering human health. This study conducted on-site investigations on gaseous pollutants emissions from different areas of a CWTP. A total of 10 pollutants were identified of which ammonia (11.32 mg/m³ in average) was the main odorous substance, and benzene (19.51 mg/m³ in average) and toluene (42.07 mg/m³ in average) were the main VOCs. The feeding workshop (FW) was considered the main source of gaseous pollutants. The Gaussian plume model demonstrated that the pollution became more serious after spreading in the southeast downwind direction. Occupational exposure risks of on-site workers were mainly attributed to hydrogen sulfide, ammonia, benzene, and toluene, as their hazard index (HI) and lifetime cancer risk (CR) exceeded the recommended occupational safety limits. The gaseous pollutants diffused from CWTP may still pose a potential health risk to residents within a range of up to 7.5 km. The emulation and quantification of ozone formation potential by methods of Propyl-Equiv and MIR demonstrated that the contribution rate of toluene presented in each stage of CWTP exceed 80 %. Toluene was also the largest contributor to secondary organic aerosol with the contribution rate reached 56.34–85.14 %, followed by benzene (14.72–38.52 %). This research provides a basis for the reduction and control of gaseous pollutants in the treatment and disposal of rural domestic waste.