ABSTRACT
Accurate quantitative evaluation of the greenhouse effects of methane(CH4) is the foundation for developing effective mitigation strategies. This study was the first to quantitatively evaluate the warming effects of the CH4 emissions from animal husbandry in China using the recently proposed climate metric GWP-star(GWP*), which is designed for short-lived climate pollutants(SLCP), and to compare the results with the commonly used climate metric global warming potential(GWP). The results showed:CH4emissions from animal husbandry in China decreased from 957.0×105 t in 2000 to 764.0×105 t. The GWP results showed that the greenhouse effect of CH4 emissions from animal husbandry in China was increasing between 2015 and 2019, and the GWP* results showed that it decreased compared to that 20 years ago. The amount of reduction was equivalent to removing the warming of 2.1×108 t of carbon dioxide. Under the GWP evaluation system, achieving carbon neutrality in the livestock industry in China requires eliminating or offsetting stable annual CH4 emissions from increased carbon sinks. Instead, under the GWP* evaluation system, China's livestock industry could achieve its carbon neutrality in the short term by effectively reducing CH4 emissions by only 0.3% per year. In the case that the livestock industry in China continues to take effective emission reduction measures, the reduction target under the GWP* metric will be reached earlier than that under GWP. Still, the choice of GWP or GWP* requires careful consideration of the objectives of evaluation, the time scale of assessment, and practical operability.
ABSTRACT
In order to comprehensively assess the emission status of air pollutes from domestic waste treatment plants in mainland China, the basic statistical information of 31 provinces and cities in China was systematically collected and collated. The emission factor method was adopted to establish the 2016 list of air pollutants for the harmless treatment of domestic garbage in mainland China. The results showed that in 2016, the total amount of CH4, VOCs, NH3, TSP, PM10, and PM2.5 gaseous pollutants discharged from domestic waste landfills was 3472084.50, 185117.10, 66.45, 54.94, 25.99, and 3.92 t, respectively. The total amount of CH4, SO2, NOx, NH3, VOCs, CO, TSP, PM10,PM2.5, and BC of gaseous pollutants discharged from incineration facilities was 25389.10, 6419.30, 70923.84, 221.36, 435.33, 3025.19, 221.36, 221.36, 2.21, and 2.86 t, respectively. Through the analysis of solid waste treatment sources, partial, and temporal distribution characteristics of air pollutants, and the proportion of incineration plants in the provinces and municipalities to the number of household harmless waste treatment plants, it was determined that the total amount of gaseous pollutants discharged from domestic waste incineration sources and landfill sources had an upward trend during the period 2010-2016. In 2016, domestic landfill treatment was the most important waste treatment method in China, and mainly concentrated in areas with moderate population density and large land resources, such as central and western regions. Domestic waste incineration treatment facilities are mainly concentrated in developed cities in the Yangtze River Delta, Pearl River Delta, and the Beijing-Tianjin-Hebei Region.
