scholarly journals Chemical composition of ambient PM<sub>2. 5</sub> over China and relationship to precursor emissions during 2005–2012

2017 ◽  
Vol 17 (14) ◽  
pp. 9187-9203 ◽  
Author(s):  
Guannan Geng ◽  
Qiang Zhang ◽  
Dan Tong ◽  
Meng Li ◽  
Yixuan Zheng ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Power Plants ◽  
Emission Inventory ◽  
Driving Forces ◽  
Measurement Data ◽  
Control Measures ◽  
Nox Emissions ◽  
Weighted Mean ◽  
National Population

Abstract. In this work, we presented the characteristics of PM2. 5 chemical composition over China for the period of 2005–2012 by synthesis of in situ measurement data collected from literatures and satellite-based estimates using aerosol optical depth (AOD) data and the GEOS-Chem chemical transport model. We revealed the spatiotemporal variations in PM2. 5 composition during 2005–2012 and investigated the driving forces behind the variations by examining the changes in precursor emissions using a bottom-up emission inventory. Both in situ observations and satellite-based estimates identified that secondary inorganic aerosols (i.e., sulfate, nitrate, and ammonium; SNA) ranked as the highest fraction of dust-free PM2. 5 concentrations, followed by organic matter (OM) and black carbon (BC). For instance, satellite-based estimates found that SNA, OM, and BC contributed to 59, 33, and 8 %, respectively, of national population-weighted mean dust-free PM2. 5 concentrations during 2005–2012. National population-weighted mean PM2. 5 concentration increased from 63.9 µg m−3 in 2005 to 75.2 µg m−3 in 2007 and subsequently decreased to 66.9 µg m−3 from 2007 to 2012. Variations in PM2. 5 concentrations are mainly driven by the decrease in sulfate and the increase in nitrate. Population-weighted mean sulfate concentration decreased by 2.4 % yr−1 during 2005–2012 (from 14.4 to 12.9 µg m−3), while population-weighted mean nitrate concentration increased by 3.4 % yr−1 during 2005–2012 (from 9.8 to 12.2 µg m−3), largely offsetting the decrease in sulfate concentrations. By examining the emission data from the Multi-resolution Emission Inventory for China (MEIC), we found that the changes in sulfate and nitrate concentrations were in line with the decrease in SO2 emissions and the increase in NOx emissions during the same period. The desulfurization regulation in power plants enforced around 2005 has been the primary contributor to the SO2 emission reduction since 2006. In contrast, growth of energy consumption and lack of control measures for NOx resulted in a persistent increase in NOx emissions until the installation of denitrification devices on power plants late in 2011, which began to take effect in 2012. The results of this work indicate that the synchronized abatement of emissions for multipollutants is necessary for reducing ambient PM2. 5 concentrations over China.

scholarly journals Chemical composition of ambient PM<sub>2.5</sub> over China and relationship to precursor emissions during 2005–2012

2017 ◽  
Author(s):  
Guannan Geng ◽  
Qiang Zhang ◽  
Dan Tong ◽  
Meng Li ◽  
Siwen Wang ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Power Plants ◽  
Emission Inventory ◽  
Nitrate Concentration ◽  
Control Measures ◽  
Nox Emissions ◽  
Sulfate Concentration ◽  
Weighted Mean ◽  
Nitrate Concentrations ◽  
Pm2.5 Concentration

Abstract. We estimated the changes in chemical composition of ambient PM2.5 over China during 2005–2012 using satellite-based aerosol optical depth (AOD) data and the GEOS-Chem chemical transport model, and investigated the driving forces behind the changes by examining the changes in precursor emissions using a bottom-up emission inventory. We found that the national population-weighted mean PM2.5 concentration increased from 63.9 μg/m3 in 2005 to 75.2 μg/m3 in 2007 (+18.19 % per year), and subsequently decreased to 66.9 μg/m3 from 2007 to 2012 (−2.67 % per year), composing a flat trend of population-weighted mean PM2.5 concentration during 2005–2012. Variations in PM2.5 concentrations are mainly driven by the changes in sulfate and nitrate concentrations. Population-weighted mean sulfate concentration increased by 10.72 % from 2005–2006 (from 14.4 μg/m3 to 15.9 μg/m3) and then decreased by 4.30 % per year from 2006–2012, dominating the variations of total PM2.5 concentrations. The decrease of sulfate concentration is partly offset by the increase of nitrate concentration: population-weighted mean nitrate concentration increased by 3.39 % per year during 2005–2012 (from 9.8 μg/m3 to 12.2 μg/m3). The changes in sulfate and nitrate concentrations were in line with the changes in SO2 and NOx emissions during the same period. By examining the emission data from the MEIC emission inventory, we found that the desulfurization regulation enforced around 2005 in power plants was the primary contributor to the SO2 emissions reduction since 2006. In contrast, growth of energy consumption and lack of control measures for NOx resulted in persistent increase in NOx emissions until the installation of denitrification devices on power plants late in 2011, which began to take effect in 2012. The results of this work indicate that the synchronized abatement of emissions for multi-pollutants are necessary for reducing ambient PM2.5 concentrations over China.

scholarly journals Growth in NOx emissions from power plants in China: bottom-up estimates and satellite observations

2012 ◽  
Vol 12 (10) ◽  
pp. 4429-4447 ◽  
Author(s):  
S. W. Wang ◽  
Q. Zhang ◽  
D. G. Streets ◽  
K. B. He ◽  
R. V. Martin ◽  
...  
Keyword(s):  
Power Plant ◽  
Power Plants ◽  
Emission Inventory ◽  
Transport Model ◽  
Nox Emission ◽  
Nox Emissions ◽  
Large Power ◽  
Power Plant Emissions ◽  
Tropospheric No2 ◽  
Plant Emissions

Abstract. Using OMI (Ozone Monitoring Instrument) tropospheric NO2 columns and a nested-grid 3-D global chemical transport model (GEOS-Chem), we investigated the growth in NOx emissions from coal-fired power plants and their contributions to the growth in NO2 columns in 2005–2007 in China. We first developed a unit-based power plant NOx emission inventory for 2005–2007 to support this investigation. The total capacities of coal-fired power generation have increased by 48.8% in 2005–2007, with 92.2% of the total capacity additions coming from generator units with size ≥300 MW. The annual NOx emissions from coal-fired power plants were estimated to be 8.11 Tg NO2 for 2005 and 9.58 Tg NO2 for 2007, respectively. The modeled summer average tropospheric NO2 columns were highly correlated (R2 = 0.79–0.82) with OMI measurements over grids dominated by power plant emissions, with only 7–14% low bias, lending support to the high accuracy of the unit-based power plant NOx emission inventory. The ratios of OMI-derived annual and summer average tropospheric NO2 columns between 2007 and 2005 indicated that most of the grids with significant NO2 increases were related to power plant construction activities. OMI had the capability to trace the changes of NOx emissions from individual large power plants in cases where there is less interference from other NOx sources. Scenario runs from GEOS-Chem model suggested that the new power plants contributed 18.5% and 10% to the annual average NO2 columns in 2007 in Inner Mongolia and North China, respectively. The massive new power plant NOx emissions significantly changed the local NO2 profiles, especially in less polluted areas. A sensitivity study found that changes of NO2 shape factors due to including new power plant emissions increased the summer average OMI tropospheric NO2 columns by 3.8–17.2% for six selected locations, indicating that the updated emission information could help to improve the satellite retrievals.

scholarly journals NO<sub><i>x</i></sub> emission trends over Chinese cities estimated from OMI observations during 2005 to 2015

2017 ◽  
Vol 17 (15) ◽  
pp. 9261-9275 ◽  
Author(s):  
Fei Liu ◽  
Steffen Beirle ◽  
Qiang Zhang ◽  
Ronald J. van der A ◽  
Bo Zheng ◽  
...  
Keyword(s):  
Power Plants ◽  
Emission Control ◽  
Control Measures ◽  
Nox Emissions ◽  
Ozone Monitoring Instrument ◽  
Emission Data ◽  
Bottom Up ◽  
Chinese Cities ◽  
Emission Changes ◽  
Urban Emissions

Abstract. Satellite nitrogen dioxide (NO2) observations have been widely used to evaluate emission changes. To determine trends in nitrogen oxides (NOx) emission over China, we used a method independent of chemical transport models to quantify the NOx emissions from 48 cities and seven power plants over China, on the basis of Ozone Monitoring Instrument (OMI) NO2 observations from 2005 to 2015. We found that NOx emissions over 48 Chinese cities increased by 52 % from 2005 to 2011 and decreased by 21 % from 2011 to 2015. The decrease since 2011 could be mainly attributed to emission control measures in power sector; while cities with different dominant emission sources (i.e., power, industrial, and transportation sectors) showed variable emission decline timelines that corresponded to the schedules for emission control in different sectors. The time series of the derived NOx emissions was consistent with the bottom-up emission inventories for all power plants (r = 0. 8 on average), but not for some cities (r = 0. 4 on average). The lack of consistency observed for cities was most probably due to the high uncertainty of bottom-up urban emissions used in this study, which were derived from downscaling the regional-based emission data to city level by using spatial distribution proxies.

scholarly journals Trends in China's anthropogenic emissions since 2010 as the consequence of clean air actions

2018 ◽  
Author(s):  
Bo Zheng ◽  
Dan Tong ◽  
Meng Li ◽  
Fei Liu ◽  
Chaopeng Hong ◽  
...  
Keyword(s):  
Power Plants ◽  
Driving Forces ◽  
Decomposition Analysis ◽  
Control Measures ◽  
Mitigation Measures ◽  
Anthropogenic Emissions ◽  
Index Decomposition ◽  
Clean Air ◽  
New Policies ◽  
Relative Change

Abstract. To tackle the problem of severe air pollution, China has implemented active clean air policies in recent years. As a consequence, the emissions of major air pollutants have decreased and the air quality has substantially improved. Here, we quantified China's anthropogenic emission trends from 2010–2017 and identified the major driving forces of these trends by using a combination of bottom-up emission inventory and Index Decomposition Analysis (IDA) approaches. The relative change rates of China's anthropogenic emissions during 2010–2017 are estimated as follows: −62 % for SO2, −17 % for NOx, &amp;plus;11 % for NMVOC, &amp;plus;1 % for NH3, −27 % for CO, −38 % for PM10, −35 % for PM2.5, −27 % for BC, −35 % for OC, and &amp;plus;18 % for CO2. The IDA results suggest that emission control measures are the main drivers of this reduction, in which the pollution controls on power plants and industries are the most effective mitigation measures. The emission reduction rates markedly accelerated after the year 2013, confirming the effectiveness of China's Clean Air Action that was implemented in 2013. We estimated that during 2013–2017, China's anthropogenic emissions decreased by 59 % for SO2, 21 % for NOx, 23 % for CO, 36 % for PM10, 33 % for PM2.5, 28 % for BC, and 32 % for OC. NMVOC emissions increased by 11 % and NH3 emissions remained stable from 2010–2017, representing the absence of effective mitigation measures for NMVOC and NH3 in current policies. The relative contributions of different sectors to emissions have significantly changed after several years' implementation of clean air policies, indicating that it is paramount to introduce new policies to enable further emission reductions in the future.

scholarly journals Trends in China's anthropogenic emissions since 2010 as the consequence of clean air actions

2018 ◽  
Vol 18 (19) ◽  
pp. 14095-14111 ◽  
Author(s):  
Bo Zheng ◽  
Dan Tong ◽  
Meng Li ◽  
Fei Liu ◽  
Chaopeng Hong ◽  
...  
Keyword(s):  
Power Plants ◽  
Driving Forces ◽  
Decomposition Analysis ◽  
Control Measures ◽  
Mitigation Measures ◽  
Anthropogenic Emissions ◽  
Index Decomposition ◽  
Clean Air ◽  
New Policies ◽  
Relative Change

Abstract. To tackle the problem of severe air pollution, China has implemented active clean air policies in recent years. As a consequence, the emissions of major air pollutants have decreased and the air quality has substantially improved. Here, we quantified China's anthropogenic emission trends from 2010 to 2017 and identified the major driving forces of these trends by using a combination of bottom-up emission inventory and index decomposition analysis (IDA) approaches. The relative change rates of China's anthropogenic emissions during 2010–2017 are estimated as follows: −62 % for SO2, −17 % for NOx, +11 % for nonmethane volatile organic compounds (NMVOCs), +1 % for NH3, −27 % for CO, −38 % for PM10, −35 % for PM2.5, −27 % for BC, −35 % for OC, and +16 % for CO2. The IDA results suggest that emission control measures are the main drivers of this reduction, in which the pollution controls on power plants and industries are the most effective mitigation measures. The emission reduction rates markedly accelerated after the year 2013, confirming the effectiveness of China's Clean Air Action that was implemented since 2013. We estimated that during 2013–2017, China's anthropogenic emissions decreased by 59 % for SO2, 21 % for NOx, 23 % for CO, 36 % for PM10, 33 % for PM2.5, 28 % for BC, and 32 % for OC. NMVOC emissions increased and NH3 emissions remained stable during 2010–2017, representing the absence of effective mitigation measures for NMVOCs and NH3 in current policies. The relative contributions of different sectors to emissions have significantly changed after several years' implementation of clean air policies, indicating that it is paramount to introduce new policies to enable further emission reductions in the future.

scholarly journals NO<sub>x</sub> emissions in China: historical trends and future perspectives

2013 ◽  
Vol 13 (6) ◽  
pp. 16047-16112 ◽  
Author(s):  
B. Zhao ◽  
S. X. Wang ◽  
J. Y. Xu ◽  
K. Fu ◽  
Z. Klimont ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Emission Reduction ◽  
Power Plants ◽  
Ambient Air ◽  
Control Measures ◽  
Nox Emission ◽  
Nox Emissions ◽  
Emission Scenarios ◽  
Emission Reductions ◽  
Stringent Control

Abstract. Nitrogen oxides (NOx) are key pollutants for the improvement of ambient air quality. Within this study we estimated the historical NOx emissions in China for the period 1995–2010, and calculated future NOx emissions every five years until 2030 under six emission scenarios. Driven by the fast growth of energy consumption, we estimate the NOx emissions in China increased rapidly from 11.0 Mt in 1995 to 26.1 Mt in 2010. Power plants, industry and transportation were major sources of NOx emissions, accounting for 28.4, 34.0, and 25.4% of the total NOx emissions in 2010, respectively. Two energy scenarios, a business as usual scenario (BAU) and an alternative policy scenario (PC), were developed to project future energy consumption. In 2030, total energy consumption is projected to increase by 64 and 27% from 2010 level respectively. Three sets of end-of-pipe pollution control measures, including baseline, progressive, and stringent control case, were developed for each energy scenario, thereby constituting six emission scenarios. By 2030, the total NOx emissions are projected to increase (compared to 2010) by 36% in the baseline while policy cases result in reduction up to 61% in the most ambitious case with stringent control measures. More than a third of the reduction achieved by 2030 between least and most ambitious scenario comes from power sector and more than half is distributed equally between industry and transportation sectors. Selective Catalytic Reduction dominates the NOx emission reductions in power plants, while life style changes, control measures for industrial boilers and cement production are major contributors to reductions in industry. Timely enforcement of legislation on heavy duty vehicles would contribute significantly to NOx emission reductions. About 30% of the NOx emission reduction in 2020, and 40% of the NOx emission reduction in 2030 could be treated as the ancillary benefit of energy conservation. Sensitivity analysis was conducted to explore the impact of key factors on future emissions.

scholarly journals High-resolution inventory of technologies, activities, and emissions of coal-fired power plants in China from 1990 to 2010

2015 ◽  
Vol 15 (23) ◽  
pp. 13299-13317 ◽  
Author(s):  
F. Liu ◽  
Q. Zhang ◽  
D. Tong ◽  
B. Zheng ◽  
M. Li ◽  
...  
Keyword(s):  
High Resolution ◽  
Power Plant ◽  
Power Plants ◽  
Emission Inventory ◽  
Control Measures ◽  
Growth Trend ◽  
Large Power ◽  
Unit Level ◽  
Power Plant Emissions ◽  
Plant Emissions

Abstract. This paper, which focuses on emissions from China's coal-fired power plants during 1990–2010, is the second in a series of papers that aims to develop a high-resolution emission inventory for China. This is the first time that emissions from China's coal-fired power plants were estimated at unit level for a 20-year period. This inventory is constructed from a unit-based database compiled in this study, named the China coal-fired Power plant Emissions Database (CPED), which includes detailed information on the technologies, activity data, operation situation, emission factors, and locations of individual units and supplements with aggregated data where unit-based information is not available. Between 1990 and 2010, compared to a 479 % growth in coal consumption, emissions from China's coal-fired power plants increased by 56, 335, and 442 % for SO2, NOx, and CO2, respectively, and decreased by 23 and 27 % for PM2.5 and PM10 respectively. Driven by the accelerated economic growth, large power plants were constructed throughout the country after 2000, resulting in a dramatic growth in emissions. The growth trend of emissions has been effectively curbed since 2005 due to strengthened emission control measures including the installation of flue gas desulfurization (FGD) systems and the optimization of the generation fleet mix by promoting large units and decommissioning small ones. Compared to previous emission inventories, CPED significantly improved the spatial resolution and temporal profile of the power plant emission inventory in China by extensive use of underlying data at unit level. The new inventory developed in this study will enable a close examination of temporal and spatial variations of power plant emissions in China and will help to improve the performances of chemical transport models by providing more accurate emission data.

scholarly journals NO<sub><i>x</i></sub> emission trends over Chinese cities estimated from OMI observations during 2005 to 2015

2017 ◽  
Author(s):  
Fei Liu ◽  
Steffen Beirle ◽  
Qiang Zhang ◽  
Ronald J. van der A ◽  
Bo Zheng ◽  
...  
Keyword(s):  
Power Plants ◽  
Emission Control ◽  
Control Measures ◽  
Nox Emissions ◽  
Ozone Monitoring Instrument ◽  
Power Sector ◽  
Emission Data ◽  
Chinese Cities ◽  
Emission Changes ◽  
Urban Emissions

Abstract. Satellite NO2 observations have been widely used to evaluate emission changes. To determine trends in NOx emission over China, we used a method independent of chemical transport models to quantify the NOx emissions from 48 cities and 7 power plants over China, on the basis of Ozone Monitoring Instrument (OMI) NO2 observations during 2005 to 2015. We found that NOx emissions over 48 Chinese cities increased by 52 % from 2005 to 2011 and decreased by 21 % from 2011 to 2015. The decrease since 2011 could be mainly attributed to emission control measures in power sector; while cities with different dominant emission sources (i.e. power, industrial and transportation sectors) showed variable emission decline timelines that corresponded to the schedules for emission control in different sectors. The time series of the derived NOx emissions was consistent with the bottom-up emission inventories for all power plants (r = 0.8 on average), but not for some cities (r = 0.4 on average). The lack of consistency observed for cities was most probably due to the high uncertainty of bottomup urban emissions used in this study, which were derived from downscaling the regional-based emission data to cities by using spatial distribution proxies.

scholarly journals High-resolution inventory of technologies, activities, and emissions of coal-fired power plants in China from 1990 to 2010

2015 ◽  
Vol 15 (13) ◽  
pp. 18787-18837 ◽  
Author(s):  
F. Liu ◽  
Q. Zhang ◽  
D. Tong ◽  
B. Zheng ◽  
M. Li ◽  
...  
Keyword(s):  
High Resolution ◽  
Power Plant ◽  
Power Plants ◽  
Emission Inventory ◽  
Control Measures ◽  
Growth Trend ◽  
Large Power ◽  
Unit Level ◽  
Power Plant Emissions ◽  
Plant Emissions

Abstract. This paper, which focuses on emissions from China's coal-fired power plants during 1990–2010, is the second in a series of papers that aims to develop high-resolution emission inventory for China. This is the first time that emissions from China's coal-fired power plants were estimated at unit level for a 20 year period. This inventory is constructed from a unit-based database compiled in this study, named the China coal-fired Power plant Emissions Database (CPED), which includes detailed information on the technologies, activity data, operation situation, emission factors, and locations of individual units and supplements with aggregated data where unit-based information is not available. Between 1990 and 2010, compared to a 479 % growth in coal consumption, emissions from China's coal-fired power plants increased by 56, 335 and 442 % for SO2, NOx and CO2, respectively, and decreased by 23 % for PM2.5. Driven by the accelerated economy growth, large power plants were constructed throughout the country after 2000, resulting in dramatic growth in emissions. Growth trend of emissions has been effective curbed since 2005 due to strengthened emission control measures including the installation of flue-gas desulfurization (FGD) systems and the optimization of the generation fleet mix by promoting large units and decommissioning small ones. Compared to previous emission inventories, CPED significantly improved the spatial resolution and temporal profile of power plant emission inventory in China by extensive use of underlying data at unit level. The new inventory developed in this study will enable a close examination for temporal and spatial variations of power plant emissions in China and will help to improve the performances of chemical transport models by providing more accurate emission data.

scholarly journals NOx emissions in China: historical trends and future perspectives

2013 ◽  
Vol 13 (19) ◽  
pp. 9869-9897 ◽  
Author(s):  
B. Zhao ◽  
S. X. Wang ◽  
H. Liu ◽  
J. Y. Xu ◽  
K. Fu ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Emission Reduction ◽  
Power Plants ◽  
Ambient Air ◽  
Control Measures ◽  
Nox Emission ◽  
Nox Emissions ◽  
Emission Scenarios ◽  
Emission Reductions ◽  
Stringent Control

Abstract. Nitrogen oxides (NOx) are key pollutants for the improvement of ambient air quality. Within this study we estimated the historical NOx emissions in China for the period 1995–2010, and calculated future NOx emissions every five years until 2030 under six emission scenarios. Driven by the fast growth of energy consumption, we estimate the NOx emissions in China increased rapidly from 11.0 Mt in 1995 to 26.1 Mt in 2010. Power plants, industry and transportation were major sources of NOx emissions, accounting for 28.4%, 34.0%, and 25.4% of the total NOx emissions in 2010, respectively. Two energy scenarios, a business as usual scenario (BAU) and an alternative policy scenario (PC), were developed to project future energy consumption. In 2030, total energy consumption is projected to increase by 64% and 27% from 2010 level respectively. Three sets of end-of-pipe pollution control measures, including baseline, progressive, and stringent control case, were developed for each energy scenario, thereby constituting six emission scenarios. By 2030, the total NOx emissions are projected to increase (compared to 2010) by 36% in the baseline while policy cases result in reduction up to 61% in the most ambitious case with stringent control measures. More than a third of the reduction achieved by 2030 between least and most ambitious scenario comes from power sector, and more than half is distributed equally between industry and transportation sectors. Selective catalytic reduction dominates the NOx emission reductions in power plants, while life style changes, control measures for industrial boilers and cement production are major contributors to reductions in industry. Timely enforcement of legislation on heavy-duty vehicles would contribute significantly to NOx emission reductions. About 30% of the NOx emission reduction in 2020 and 40% of the NOx emission reduction in 2030 could be treated as the ancillary benefit of energy conservation. Sensitivity analysis was conducted to explore the impact of key factors on future emissions.

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