Characteristics of CH4 and VOCs emissions from municipal solid waste landfills in China

To assess the emission status of primary gas emissions such as methane (CH4) and VOCs from municipal solid waste (MSW) landfills in China comprehensively and promote the understandings of the reduction potential of air and greenhouse gas emissions in waste sector, this study collected the fundamental information of waste treatment in 695 cities nationwide. Based on the emission factor method, it calculated the emissions of CH4, VOCs, and other typical air pollutants from urban landfills in China from 2002 to 2022. The results show that the MSW disposed in landfills in China has been decreasing after 2009. The decline rate was lowest in 2021 (1.39%), while highest in 2020 (12.45%). In 2022, the total emissions of CH4, NH3, VOCs, TSP, PM10, and PM2.5 from urban landfills in China were 4.09×106, 17.04, 4.75×104, 14.09, 6.66, and 1.00 ton respectively. In terms of spatial distribution, the regions with significant emissions of CH4 and volatile organic compounds (VOCs) from MSW landfills in China have experienced a southward migration. Since 2018, there has been a sustained reduction in the emissions of these air pollutants, with the rate of decline ranging from a minimum of 2.75% in 2018 to a maximum of 41.57% in 2022. Post-2020, emissions of CH4have followed a similar downward trajectory, with a minimum reduction of 4.53% observed in 2020 and a peak decrease of 13.56% in 2022. Over the past few years, there has been a notable decrease in the CH4 and VOCs emissions from landfills in China. This trend correlates with a reduction in the volume of waste being disposed in the landfills, where the rate of decline for air pollutants has exceeded that observed for CH4 emissions. © 2024 Chinese Society for Environmental Sciences. All rights reserved.