Heterogeneous variations on historical of mercury, dioxins, and CO2 emissions from medical waste incineration process in China: Emission inventory, driving factors, and the impact of COVID-19

Abstract

Medical waste incineration (MWI) is one of the important sources of carbon dioxide (CO₂) and hazardous air pollutants (HAPs), threatening the triple planetary environmental crisis of climate change, biodiversity loss, and environmental pollution. Utilizing the EMEP/EEA air pollutant emission inventory and the IPCC 2006 guidelines, this study develops a comprehensive inventory of anthropogenic mercury (Hg), dioxins (PCDD/Fs), and CO₂ emissions from the MWI process in China among 2014-2023, employing a bottom-up approach at the plant level. The findings indicate that national MWI emissions of Hg, PCDD/Fs, and CO₂ increased by 1.33, 2.23, and 1.17 times, respectively, across Chinese mainland from 2014 to 2023. Notably, the response to the COVID-19 pandemic has led to a sudden increase of both Hg and PCDD/Fs emissions in the MW incineration process in China, particularly in 2022. Random forest model analysis identifies GDP and total population as key determinants of MWI, with feature importance values of 0.617 (P < 0.05) and 0.100 (P < 0.05), respectively. Additionally, a geographical detector analysis reveals that GDP, openness, and urbanization significantly influence pollutant and CO₂ emissions, with temporal variations in significance. These results provide critical insights for formulating medical waste disposal policies, promoting sustainable management practices in China, and enhancing preparedness for future health emergencies.

Keywords: COVID-19 pandemic; Emission inventory; Geographical detector; Medical waste incineration (MWI); Random Forest model.