A systematic assessment of city-level climate change mitigation and air quality improvement in China.

China is facing dual challenges of air pollution and climate change. By using city-level data, we comprehensively assessed air quality and CO2 emission changes from 2015 to 2019 for 335 Chinese cities. We selected important regions for air pollution control and categorized all cities into different classes according to their development levels. Our novel approach revealed new insights on different patterns of changes of PM2.5, O3, and CO2 by region and city class. We found that PM2.5 concentrations decreased remarkably due to mandatory city-level reduction targets, especially in the Beijing-Tianjin-Hebei (-27%) region. Nonetheless, O3 concentrations and CO2 emissions increased in 91% and 69% of Chinese cities, respectively. Observed CO2 emission reductions in more developed cities were mainly due to prominent energy intensity reduction and energy structure improvement. Our study indicates a lack of synergy in air pollution control and CO2 mitigation under current policies in China. To address both challenges holistically, we suggest setting mandatory city-level CO2 emission reduction targets and reinforcing clean energy and energy efficiency measures.

Air pollution emissions from Chinese power plants based on the continuous emission monitoring systems network.

To meet the growing electricity demand, China's power generation sector has become an increasingly large source of air pollutants. Specific control policymaking needs an inventory reflecting the overall, heterogeneous, time-varying features of power plant emissions. Due to the lack of comprehensive real measurements, existing inventories rely on average emission factors that suffer from many assumptions and high uncertainty. This study is the first to develop an inventory of particulate matter (PM), SO2 and NOX emissions from power plants using systematic actual measurements monitored by China's continuous emission monitoring systems (CEMS) network over 96-98% of the total thermal power capacity. With nationwide, source-level, real-time CEMS-monitored data, this study directly estimates emission factors and absolute emissions, avoiding the use of indirect average emission factors, thereby reducing the level of uncertainty. This dataset provides plant-level information on absolute emissions, fuel uses, generating capacities, geographic locations, etc. The dataset facilitates power emission characterization and clean air policy-making, and the CEMS-based estimation method can be employed by other countries seeking to regulate their power emissions.

[Contribution of Emissions from Cement to Air Quality in China].

This study analyzed the concentrations of exhaust gas in the process (kiln head and kiln tail) of China's cement industry, based on data from continuous emission monitoring systems network in 2018. The cement emission inventory for China with high resolution (high resolution cement emission inventory for China, HCEC), using the bottom-up approach, was established. The results indicated that during 2018, the total emissions of PM, SO2, and NOx were 72893, 92568, and 878394 t, respectively. In terms of temporal evolution, the exhaust concentration of flue gas in the main process gradually decreased, with obvious emission reduction from the Blue Sky Protection Campaign. Regionally, the exhaust concentrations of flue gas of the kiln head and kiln tail in Beijing-Tianjin-Hebei and surrounding areas, and the Yangtze River Delta and Fenwei Plain, showed a considerable decline, with a high to average level in China. The flu concentrations of each city differed; the cement industry in Anhui Province generated the largest emission in the country, while Beijing and Tianjin showed the highest emission intensity per unit area.

[Inventory and Distribution Characteristics of China's Thermal Power Emissions Under Ultra-Low Reconstruction].

This study updates a bottom-up high-resolution emission inventory and estimates the concentrations, emission factors, emissions, and performance values of China's power plants, based on the data from continuous emission monitoring systems and environmental statistics in 2018. The results show that the ultra-low emission policy has significant effects: the average concentrations of SO2, NOx, and PM in thermal power plants were 37.57, 56.71, and 7.41 mg ·m-3, respectively in 2018, which were 58.71%, 43.12%, and 60.79% lower than those in 2015. The average emission factors of SO2, NOx, and PM from coal-fired units in China were 0.3, 0.48, and 0.06 g ·kg-1, respectively, which were 55.2%, 36.84%, and 62.5% lower than those in 2015. The total emissions of SO2, NOx, PM, and PM2.5in thermal power plants were 721.4, 1183.8, 149.0, and 135.9 kt ·a-1, respectively, down by 41.32%, 19.29%, 48.12%, and 40.39% from 2015.

Graphitic carbon nitride-doped sewage sludge as a novel material for photodegradation of Eriochrome Black T.

The bio-resource utilization of sewage sludge is presented by preparation of novel waste sludge-doped graphite carbon nitride (g-C3N4) photocatalyst. The sludge flocs which constitute bacteria and organic substances served as a pore-forming framework in the catalyst, while the inorganic fractions including those transition metals and crustal metals can function as dopants for sludge-based g-C3N4 composite. The physicochemical properties of as-prepared catalyst were well analyzed by multiple characterizations. The composite catalyst showed higher surface area (50 m2/g) and more mesoporous structures (8.9 × 10-2 cm3/g) as compared with pristine g-C3N4 (8.4 m2/g and 6.6 × 10-2 cm3/g, respectively). The photoelectrochemical results showed that introduced sewage sludge impurities lowered down the photocarriers recombination efficiency and enhanced more efficient electron-hole separation by about 100 times. The photocatalytic activity was tested by degradation of typical dye Eriochrome Black T (EBT). The optimal sample improved removal of EBT by 56% in 90 min under ultraviolet irradiation (λ = 254 nm). According to the results of main metal ion leaching concentration and reuse tests, the composite catalyst exhibited excellent stability and repeatability.

The valuation of China's environmental degradation from 2004 to 2017.

This paper aims to evaluate the cost of environmental degradation by adopting the conventional environmental economic methodology in China from 2004 to 2017 and summarize the change in both the causes and costs of China's environmental degradation. Results from this study revealed the following: i. The environmental degradation cost in China increased from 511 billion yuan to 1,892 billion yuan from 2004 to 2017, and its share in the GDP decreased from 3.05% to 2.23%; ii. The environmental degradation cost growth rate was lower than the GDP growth rate. The environmental degradation cost growth rate decreased sharply, by dropping from 10% in 2014 to 2% in 2017. The environmental benefits of industrial transformation have emerged; iii. The provinces of Shandong, Hebei, Jiangsu, Henan, and Guangdong had the highest environmental degradation costs. The annual average growth rate of the environmental degradation costs in Jiangsu, Guangdong, and Zhejiang were lower than their growth rate of the GDP respectively; iv. Consideration of environmental degradation cost in decision-making could contribute to the high-quality development of China.

Spatial-temporal characteristics of phosphorus in non-point source pollution with grid-based export coefficient model and geographical information system.

In this paper, the spatial changes and trends in non-point source (NPS) total phosphorus (TP) pollution were analyzed by land and non-land uses in the Songliao River Basin from 1986 to 2000 (14 years). A grid-based export coefficient model was used in the process of analysis based on to a geographic information system. The Songliao Basin is divided in four regions: Liaoning province, Jilin province (JL), Heilongjiang province and the eastern part of the Inner Mongolia (IM) Autonomous Region. Results indicated that the NPS phosphorus load caused by land use and non-land use increased steadily from 3.11×10(4) tons in 1986 to 3.49×10(4) tons in 2000. The southeastern region of the Songliao Plain was the most important NPS pollution contributor of all the districts. Although the TP load caused by land use decreased during the studied period in the Songliao River Basin, the contribution of land use to the TP load was dominant compared to non-land uses. The NPS pollution caused by non-land use steadily increased over the studied period. The IM Autonomous Region and JL province had the largest mean annual rate of change among all districts (more than 30%). In this area, livestock and poultry breeding had become one of the most important NPS pollution sources. These areas will need close attention in the future.