[Dual-Perspective Analysis of the Warming Effect of the Methane Emissions from Animal Husbandry in China].

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.

[Emission Inventory of Air pollutants for the Harmless Treatment of Municipal Solid Waste].

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.

[Comparative Analysis and Inspiration of Air Quality Index Between China and America].

Research on the differences of air quality index (AQI) especially AQI of particulate matters between China and America and analysis of hourly monitored readings from April to December in 2013 released by Environmental Monitoring Station of China indicated that: (1) Although China lagged behind America in formulating and publishing of AQI standards, the AQI standards published in 2012 in China covered more pollutant indexes than before and could objectively reflect the characteristics of air pollution in China, and were more close to the residens's feeling about air quality. (2) The methods adopted for calculation of particulate matter hourly AQI were different in China and America, and the comparison revealed that the calculation method adopted by China using the 24 h average concentration breakpoint of particulate matters to replace the 1 h average concentration breakpoint would enhance the severity of the pollution level. (3) The breakpoint of PM2.5 -24 h in China was less rigorous than that in America when AQI < 200, which led to the inconsistence between the ratio of PM2.5/PM10 and the real situation in China. (4) Analysis on the monitoring readings from station of Beijing Olympic Sports Center showed that when AQI < 50, the ratio of PM2.5/PM10 was less than 0.5 and increased with.the increasing of AQI. Correction and adjustment of particulate matter real-time calculation method and breakpoints of PM2.5 and PM10 were suggested in China.

[Comparative Analysis on the Improvement of Air Quality in Beijing During APEC].

In order to evaluate the effects of the implementation of emission reduction measures and the revolution of air quality of Beijing during APEC, the evolution characteristics of air quality was analyzed based on the hourly monitored readings of Olympic Sports Center from 1 to 15 November 2014 released by Environmental Monitoring Station of China, and compared with that in 2013. The results showed that: (1) PM2.5 was the main pollutant in Beijing. The air quality was good during the period of APEC with three obvious pollution events, and it was better than that in the same period in 2013, indicating that the implementation of emission reduction measures had made significant contribution to the improvement of air quality. (2) During the period of APEC, the concentrations of PM2.5 of 5 days were below the World Health Organization (WHO) standard (25 µg · m⁻³), and the concentration of SO2 met the WHO standard during this time. (3) During the period of APEC, the ratio of PM2.5, and PM10 was less than 0.5 when the air quality was good, and gradually increased with the increasing pollution level. The ratio reached 0.9 when the air was seriously polluted. (4) Compared with the same time in 2013, although the implementation of emission reduction measures made contribution to the reduction of the concentration of PM2.5, its contributions to the reduction of SO2 and CO concentration were much more obvious than that of PM2.5, and it had little impact on the reduction of NO2 concentration, and the reduction order of pollutants emission was SO2 > CO > PM > NO2, indicating that the sources, effects and emission reduction of PM2.5 were complex, and further studies are required.

[Analysis on Regional Characteristics of Air Quality Index and Weather Situation in Beijing and Its Surrounding Cities During the APEC].

Analysis on the revolution and regional characteristics of air quality by hourly monitored readings from 1 to 15 November 2014 released by Environmental Monitoring Station of China and research of the impacts of weather situation and meteorological elements released by China Meteorological Administration towards air quality of Beijing and its surrounding cities during the Asia-Pacific Economic Cooperation (APEC) indicated that: (1) The air quality was good because of the implementation of mitigation measures, while the Air Quality Index (AQI) increased along with the termination of mitigation measures. Thus it can be seen that mitigation measures made a great contribution to the improvement of air quality of Beijing and its surrounding cities. (2) Affected by thermal inversion layer, AQI of Beijing and its surrounding cities increased quickly during the initial of the implemental of reducing measures which proved that pollutants would accumulate in the context of unfavourable weather, hence the influence of weather situation towards air quality could not be ignored. (3) Although affected by thermal inversion layer, the concentration of pollutants of Beijing was not accumulated to a high degree at the end period of reducing measures, while Tianjin, Tangshan, Baoding and Xingtai suffered from moderate and severe pollution at the same time which further illustrated that the implementation of mitigation measures have made a great contribution to the improvement of air quality in Beijing during APEC.