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.

[Contribution of Emissions from the Iron and Steel Industry to Air Quality in China].

Based on the data from a continuous emission monitoring systems network in 2015, this study analyzed the compliance rates of exhaust gas in the processes of China's iron and steel industry, and established a high-resolution steel plant emission inventory for China (HSEC, 2015), based on the bottom-up method. The contribution of emissions from the iron and steel industry to regional air quality was quantitatively simulated using a CAMx model. The results showed that in 2015, the total emissions of SO2, NOx, PM10, PM2.5, PCDD/Fs, VOCs, CO, BC, OC, EC, and F were 374800 t, 720500 t, 334800 t, 150300 t, 1.91 kg, 842900 t, 34788500 t, 6400 t, 8300 t, 800 t, and 7700 t, respectively. From a regional perspective, the iron and steel industry in Shanghai and Tianjin has the highest emission intensity per unit area and contributes a high proportion to regional air pollution. From a process perspective, in 2015, the exhaust concentration of flue gas in the main process gradually decreased, with a high compliance rate, and the emission factor significantly decreased to lower than that in the existing research results. From a species perspective, in 2015, NOx emission from the steel industry contributed the most to regional air quality, and there is therefore a great emission reduction potential for NOx.