Emissions Of Major Air Pollutants Research Articles

Low-carbon energy policies benefit climate change mitigation and air pollutant reduction in megacities: An empirical examination of Shenzhen, China

The low-carbon transformation of energy system has great significance for megacities to mitigate climate change, which brings co-benefits to improve urban air quality. Taking China's megacity, Shenzhen, as an example, this study examines the potential of wide-ranging energy policies in urban GHG emission reduction and the associated synergistic effect on decreasing major air pollutant emissions. Based on the low emissions analysis platform (LEAP) model, the major results show that an effective implementation of newly emerging energy policies could help cap GHG emissions of Shenzhen in 2025 and nearly halve them by 2035, which would contribute substantially to reducing urban air pollutant emissions. At the sectoral level, the synergistic effect of emission reduction would be the strongest in the transportation sector, followed by the electricity and manufacturing sectors, while it is not significant in the building sector. Moreover, all policies on energy efficiency improvement and demand management that reduce fossil energy consumption show synergistic effects on decreasing air pollutants, while policies on energy structural optimization show differentiated impacts across SO2, NOx, VOCs, and PM2.5. Urban managers should prioritize energy policies with strong synergistic effects and specifically promote the wide application of rooftop PV system and deep electrification of road transportation.

Spatiotemporal Dynamic Correlation Characteristics and Driving Factors of Major Air Pollutant Emissions in China

Air pollution is closely associated with human health and the economy. Therefore, it is important to understand variations in the spatiotemporal and sectoral emission distributions of major air pollutants and their drivers. The policies (APAPPC) promulgated by China in 2013 have also achieved remarkable results. Rate of change, trend analysis, and a geographically and temporally weighted regression model were used to study the effects of socioeconomic factors on NOx, SO2, and dust emissions in China during 2011–2017. During the study period, annual average emissions of NOx, SO2, and dust decreased by 11.45, 13.42, and 4.82 Mt (−47.64, −60.53, and −39.05%), respectively. Pollutant emissions were concentrated in North China, with Shandong and Hebei provinces exhibiting the highest NOx and SO2 and dust emissions, respectively. Pollutant emissions from the power and industrial sectors were mainly distributed in East (27.08 and 28.00%, respectively) and North China (23.57 and 20.04%, respectively), whereas emissions from the residential sector were mainly concentrated in North (22.48%) and Southwest China (20.07%). Pollutant emissions were positively correlated with electricity generation, urban population density, urban green spaces, private car ownership, the secondary industry as a share of regional GDP, and steel production and negatively correlated with disposable income and gross construction output. Per capita disposable income was the dominant driving factor.

Coordinated effects of energy transition on air pollution mitigation and CO2 emission control in China

China has made progress in energy transition to improve air quality, but still confronts challenges including further ambient PM2.5 reduction, O3 pollution mitigation, and CO2 emission control. To explore the coordinated effects of energy transition on air quality and carbon emission in the near term in China, we designed 4 scenarios in 2025 based on different projections of energy transition progress with varying end-of-pipe control level, in each of which we calculated emissions of major air pollutants and CO2, and simulated ambient PM2.5 and O3 concentrations. Results show that energy transition has disparate effects on emission reduction of different air pollutants and sectors, which largely depends on their current end-of-pipe control levels. The different effects on emission reduction may result in opposite variation tendencies of ambient PM2.5 and O3 concentration in a future scenario with aggressive energy transition policies and end-of-pipe control level in 2018. With the end-of-pipe control level strengthened in 2025, PM2.5 and O3 concentration could both reduce on the national scale, but the reduction of ambient O3 lags behind PM2.5, indicating the difficulty of O3 pollution control. As to CO2, national emission would go up in 2025 either implementing current or aggressive energy transition policies due to growing needs of electricity and on-road transportation, but emissions in most provinces could decline to below the 2018 level with aggressive energy transition policies because of substitution of clean energy in industrial, residential and off-road transportation sectors. The study results suggest strictly implementing restrictive end-of-pipe control measures along with energy transition to simultaneously reduce ambient PM2.5 and O3 concentration, and accelerating substitution of renewable energy in power sectors where electricity generation grows rapidly to synergistically control air pollution and CO2 emissions. Furthermore, the projection of CO2 emissions could provide references for short-term emission control targets from the perspective of air quality improvement.

Urban residential energy switching in China between 1980 and 2014 prevents 2.2 million premature deaths

Urban residential energy switching in China between 1980 and 2014 prevents 2.2 million premature deaths

A data-driven method of traffic emissions mapping with land use random forest models

The development of intelligent approaches to quantify and mitigate on-road emissions is essential for urban and transportation sustainability for global megacities. Here, we utilize high-density traffic monitoring data and land use data to train random forest models capable of accurately predicting dynamic, link-level vehicle emissions. A total of 272 predicting indicators, including road features, population density, and land use information, were included in model training. Our model performed well, with a spatial generalization R2 > 0.8 for both volume and speed simulations. Dynamic link-based emissions of major air pollutants and carbon dioxide (CO2) were estimated for the whole road network of Chengdu, a populous city with the second greatest vehicle population in China. We adopted a generalized additive model to identify the drivers of spatial heterogeneity of on-road emissions and energy consumption, and nonlinear relationships between emissions, demographic and land use variables were found. Fine-grained assessments of emission reductions from potential Low Emission Zone policies are explored based on the high-resolution vehicle emission mapping tool. With high computational efficiency, the method is promising for handling traffic data streams in a real-time fashion, thus offering the potential for more precise vehicle emission management and carbon footprint tracking.

Field-based measurements of major air pollutant emissions from typical porcelain kiln in China

China has been famous for its porcelains for millennia, and the combustion processes of porcelain production emit substantial amounts of air pollutants, which have not been well understood. This study provided firsthand data of air pollutant emissions from biomass porcelain kilns. The emission factor of PM2.5 was 0.95 ± 1.23 g/kg during the entire combustion cycle, lower than that of biomass burning in residential stoves and coal burning in brick kilns, attributed to the removal effects of the long-distance transport in dragon kilns. The temporal trend of particle pollutants, including particulate matters (PMs) and particulate polycyclic aromatic hydrocarbons (PAHs) (low at ignition phase and high at the end) again indicated the removal effects of the special structure, while gaseous pollutants, such as gaseous PAHs, exhibited the opposite result. The GWC100 was estimated as 1.4 × 106 and 0.5 × 106 kg CO2e/yr for the scenarios in which 50% and 100% of the wood was renewable, respectively. The GWC100 of dragon kilns is nearly equal to that of 745 households using wood-fueled stoves. These results indicate the necessity of pollution controls for biomass porcelain kilns to estimate the emission inventory and climate change.

Mapping the drivers of formaldehyde (HCHO) variability from 2015 to 2019 over eastern China: insights from Fourier transform infrared observation and GEOS-Chem model simulation

Abstract. The major air pollutant emissions have decreased, and the overall air quality has substantially improved across China in recent years as a consequence of active clean air policies for mitigating severe air pollution problems. As key precursors of formaldehyde (HCHO) and ozone (O3), the volatile organic compounds (VOCs) in China are still increasing due to the lack of mitigation measures for VOCs. In this study, we investigated the drivers of HCHO variability from 2015 to 2019 over Hefei, eastern China, by using ground-based high-resolution Fourier transform infrared (FTIR) spectroscopy and GEOS-Chem model simulation. Seasonal and interannual variabilities of HCHO over Hefei were analyzed and hydroxyl (OH) radical production rates from HCHO photolysis were evaluated. The relative contributions of emitted and photochemical sources to the observed HCHO were analyzed by using ground-level carbon monoxide (CO) and Ox (O3 + nitrogen oxide (NO2)) as tracers for emitted and photochemical HCHO, respectively. Contributions of emission sources from various categories and geographical regions to the observed HCHO summertime enhancements were determined by using a series of GEOS-Chem sensitivity simulations. The column-averaged dry air mole fractions of HCHO (XHCHO) reached a maximum monthly mean value of 1.1 ± 0.27 ppbv in July and a minimum monthly mean value of 0.4 ± 0.11 ppbv in January. The XHCHO time series from 2015 to 2019 over Hefei showed a positive change rate of 2.38 ± 0.71 % per year. The photochemical HCHO is the dominant source of atmospheric HCHO over Hefei for most of the year (68.1 %). In the studied years, the HCHO photolysis was an important source of OH radicals over Hefei during all sunlight hours of both summer and winter days. The oxidations of both methane (CH4) and nonmethane VOCs (NMVOCs) dominate the HCHO production over Hefei and constitute the main driver of its summertime enhancements. The NMVOC-related HCHO summertime enhancements were dominated by the emissions within eastern China. The observed increasing change rate of HCHO from 2015 to 2019 over Hefei was attributed to the increase in photochemical HCHO resulting from increasing change rates of both CH4 and NMVOC oxidations, which overwhelmed the decrease in emitted HCHO. This study provides a valuable evaluation of recent VOC emissions and regional photochemical capacity in China. In addition, understanding the sources of HCHO is a necessary step for tackling air pollution in eastern China and mitigating the emissions of pollutants.

Contributors to Air Pollutant Emission Changes in Autumn and Winter in Beijing-Tianjin-Hebei and Surrounding Areas

Based on the air pollution emission inventory technical methodology, this study conducted a quantitative analysis on the changes in major air pollutant emissions in Beijing-Tianjin-Hebei and its surrounding areas from the 'New Year Haze' in the autumn and winter of 2016-2017 to the 'Pandemic Haze' in the autumn and winter of 2019-2020. The contributions of the implementation of air pollution prevention and control policies and the COVID-19 pandemic to major air pollutant emission reductions were studied, and their impacts on the regional air quality under adverse meteorological conditions were simulated using an air quality model. The results showed that from the 'New Year Haze' in Dec 2016-Jan 2017 to the 'Pandemic Haze' in Jan-Feb 2020, the major air pollutant emissions in the region had dropped by approximately 50%, and the average concentration of PM2.5 was potentially reduced by more than 40% under adverse meteorological conditions. The most effective emission reduction measures included the clean heating project and raising the standards in key industrial sectors, such as the iron and steel industry, coal-fired boilers, and power plants, which contributed 67.1% and 53.4% of the emission reductions in SO2 and PM2.5, respectively. The COVID-19 pandemic predominantly affected the mobile sources and light industry, which contributed 71.9% and 68.2% of the emission reductions in NOx and VOCs, respectively. The implementation of air pollution prevention and control policies contributed substantially to the improvement of regional air quality, which effectively reduced the intensity and extent of the heavy pollution process under unfavorable meteorological conditions. The regional average PM2.5 concentration was reduced by 26%, and the number of days experiencing heavy pollution decreased by 44%. Due to the impacts of the COVID-19 pandemic, the average PM2.5 concentration in the region was reduced by an additional 24%, and the duration and extent of heavy pollution decreased even further.

Emissions of air pollutants from sintering flue gas in the Beijing-Tianjin-Hebei area and proposed reduction measures

Iron and steel manufacturing, especially the sintering process, is highly energy- and pollution-intensive, and is responsible for substantial emissions of major air pollutants in China, including particulate matter (PM), sulfur dioxide (SO2), and nitrogen oxides (NOx), which poses challenges to air quality improvement in the country. In this study, we carried out a comprehensive analysis of the temporal and spatial characteristic of SO2, NOx, and PM emission concentrations, quantified the standard-reaching rate and air pollutant emissions factors, as well as discussed the spatial distribution and potential reduction measures of emission amounts based on the hourly online monitoring data and basic information collected from sintering head process in the Beijing-Tianjin-Hebei region (BTH) in 2017. We found that there was a downward trend of monthly emission concentrations during September to December 2017, in response to the emission control policies. By comparing with the emission standard implemented in 2017, the standard-reaching rate of PM, NOx, and SO2 were 74.7%, 23.5%, and 62.5% respectively, higher relative to the ultra-low emission standard. The emission factors of PM, NOx, and SO2 were calculated at different sintering machine scales, and were found to be lower than previous estimates. The emissions of SO2, NOx, and PM from sintering machine heads in the BTH region amounted to 14.2 kt, 143.2 kt and 46.3 kt respectively, Tangshan and Handan accounted for over 60% of the total emission amounts. The most popular technologies applied for PM and SO2 removals are electrostatic precipitators and limestone-gypsum flue gas desulfurization with an average removal efficiency of 71.8% and 90.3%. The potential of NOx reduction is huge, more effective technical measures shall be adopted to further reduce the NOx emission amount during the sintering process.

A data-driven study of IMO compliant fuel emissions with consideration of black carbon aerosols

The shipping industry has been facing increasing pressure to reduce environmental emissions. For instance, starting in 2020 the International Maritime Organization (IMO) required a reduction of the global sulfur limit for shipping fuels outside designated Sulfur Emission Control Areas (SECA) from 3.5% to 0.5% on a mass basis. Other pollutants are also being targeted for short-term and long-term reduction.Aiming at providing sustainable fuel solutions for the stage of tank to propeller, this manuscript evaluates various shipping fuel options focusing on quantitatively comparing the fuel consumption and emissions of major air pollutants. A bottom-up emission inventory model is developed by analyzing and optimizing multiple sources of load factors, specific fuel consumption and emission factors. Rather than taking deterministic emission leading values, this work improves the model quality by considering external factors and the latest emission data and processing a detailed ship-by-ship calculation for the ship database collected by the shipboard Automatic Identification System (AIS). The amounts of carbon dioxide for the main engine, auxiliary engine and auxiliary boilier are firstly calculated, and then the fuel consumption per nautical mile are computed by integrating CO2 intensity. Next, ship exhaust gases are calculated for two categories: (i) gases impacting the global warming potential (GWP) and (ii) the non-GWP gases. Besides sustainable solutions within one specific ship fleet, this work firstly establishes a nautical mile-based fuel consumption per unit of capacity bin for major merchant ships to serve as a basis for finding an optimized fuel solution among different ship types. In addition to addressing the typical ship-source pollutants, this work also focuses on negative environmental effects resulting from BCA because it has not been thoroughly considered in the literatures despite its contribution to GWP. To illustrate the value and applicability of the proposed approach, a case study is solved to estimate the cumulative fuel consumption and GWP-related gas emission inventory for a transoceanic trip from Houston to Rotterdam. The results demonstrate that the GWP gas emissions of heavy fuel oil with scrubber are 38% more than those of one LNG dual-engine option. Explicit consideration is also given to BCA emissions. The results indicate that the blended fuel aimed at satisfying the IMO 2020 Sulfur Cap does not perform well in BCA emission control.

Dynamic projection of anthropogenic emissions in China: methodology and 2015–2050 emission pathways under a range of socio-economic, climate policy, and pollution control scenarios

Abstract. Future trends in air pollution and greenhouse gas (GHG) emissions for China are of great concern to the community. A set of global scenarios regarding future socio-economic and climate developments, combining shared socio-economic pathways (SSPs) with climate forcing outcomes as described by the Representative Concentration Pathways (RCPs), was created by the Intergovernmental Panel on Climate Change (IPCC). Chinese researchers have also developed various emission scenarios by considering detailed local environmental and climate policies. However, a comprehensive scenario set connecting SSP–RCP scenarios with local policies and representing dynamic emission changes under local policies is still missing. In this work, to fill this gap, we developed a dynamic projection model, the Dynamic Projection model for Emissions in China (DPEC), to explore China's future anthropogenic emission pathways. The DPEC is designed to integrate the energy system model, emission inventory model, dynamic projection model, and parameterized scheme of Chinese policies. The model contains two main modules, an energy-model-driven activity rate projection module and a sector-based emission projection module. The activity rate projection module provides the standardized and unified future energy scenarios after reorganizing and refining the outputs from the energy system model. Here we use a new China-focused version of the Global Change Assessment Model (GCAM-China) to project future energy demand and supply in China under different SSP–RCP scenarios at the provincial level. The emission projection module links a bottom-up emission inventory model, the Multi-resolution Emission Inventory for China (MEIC), to GCAM-China and accurately tracks the evolution of future combustion and production technologies and control measures under different environmental policies. We developed technology-based turnover models for several key emitting sectors (e.g. coal-fired power plants, key industries, and on-road transportation sectors), which can simulate the dynamic changes in the unit/vehicle fleet turnover process by tracking the lifespan of each unit/vehicle on an annual basis. With the integrated modelling framework, we connected five SSP scenarios (SSP1–5), five RCP scenarios (RCP8.5, 7.0, 6.0, 4.5, and 2.6), and three pollution control scenarios (business as usual, BAU; enhanced control policy, ECP; and best health effect, BHE) to produce six combined emission scenarios. With those scenarios, we presented a wide range of China's future emissions to 2050 under different development and policy pathways. We found that, with a combination of strong low-carbon policy and air pollution control policy (i.e. SSP1-26-BHE scenario), emissions of major air pollutants (i.e. SO2, NOx, PM2.5, and non-methane volatile organic compounds – NMVOCs) in China will be reduced by 34 %–66 % in 2030 and 58 %–87 % in 2050 compared to 2015. End-of-pipe control measures are more effective for reducing air pollutant emissions before 2030, while low-carbon policy will play a more important role in continuous emission reduction until 2050. In contrast, China's emissions will remain at a high level until 2050 under a reference scenario without active actions (i.e. SSP3-70-BAU). Compared to similar scenarios set from the CMIP6 (Coupled Model Intercomparison Project Phase 6), our estimates of emission ranges are much lower than the estimates from the harmonized CMIP6 emissions dataset in 2020–2030, but their emission ranges become similar in the year 2050.

Environmental Effective Assessment of Control Measures Implemented by Clean Air Action Plan (2013–2017) in Beijing, China

The Beijing government initiated the Clean Air Action Plan (CAAP) in 2013. Through a series of actions to control air pollution, the emissions of major atmospheric pollutants are reduced to improve urban air quality. In order to evaluate the effectiveness of control measures taken to mitigate atmospheric pollution, we investigated and analyzed the implementation of the CAAP in Beijing from 2013 to 2017, estimating the corresponding reduction in emissions of major air pollutants. The contribution of different control measures to the improvement of air quality was quantified and the experiences of managing air pollution were summarized, which provided references for the continuous improvement of air quality in Beijing and the surrounding areas. The results showed that the emission of SO2, NOX, PM10, PM2.5, and VOCs from air pollution source have been decreased by 119,924, 116,091, 116,810, 46,652, and 97,267 tons after the implementation of the CAAP. The sum of these five air pollutants emissions have been reduced by 39% in 2017 compared with 2013, the largest decrease in SO2 emissions was 87%, which was related to the vigorous control on coal-fired combustion. The control measure with the greatest contribution to decreasing the ambient PM2.5 concentration was the clean energy transformation of coal-fired power plants, which contributed 27% of the total reduced concentration and 6.1 μg/m3 of the average PM2.5 concentration reduction in Beijing. Clean Residential coal use also significantly decreased the PM2.5 concentration by 5.4 μg/m3, which was 23% of the total reduction. In addition, the industrial restructuring and the management of automotive vehicle use and dust could also contribute to efficiently reducing the PM2.5 concentration by 4.0, 3.2, and 2.3 μg/m3, or 17%, 14%, and 10% of the total reduction, respectively. Due to the implementation of control measures of Clean Air Action Plan, the energy and industrial structure of Beijing have been adjusted and optimized, leading to the reduction of pollutant emissions, which is the secret of urban long-term air quality improvement.

Decomposition Analysis of Factors that Drive the Changes of Major Air Pollutant Emissions in China at a Multi-Regional Level

The regional emission reduction determines the national emission reduction for one country, and the differences in regional economic characteristics may result in regional differences in air pollutant emissions (APEs). In this regard, this study constructs a regional contribution index of different factors through an extended LMDI (Logarithmic Mean Divisia Index) method and investigates regional differences in factors driving the changes of China’s major APEs (SO2, NOx, and PM2.5). It reveals that the regional emission efficiency effect was a key inhibitory factor on APEs, which was more obvious in the eastern and northern regions. The regional energy intensity had greater inhibitory effects on SO2 and NOx than on PM2.5, and these inhibitory effects were more obvious in the eastern region. The regional population structure promoted APEs for northern, southern, northeastern, and eastern regions, and inhibited APEs for central, southwestern, and northwestern regions. The regional relative income had a slight effect, which curbed APEs for northern, eastern, southern, and northern regions. The national economic growth effect was the key factor in promoting APEs, which was obvious in eastern and northern regions, followed by southern, central, and southwestern regions. Policy implications are put forward based on empirical results.

Energy and air pollution benefits of household fuel policies in northern China

In addition to many recent actions taken to reduce emissions from energy production, industry, and transportation, a new campaign substituting residential solid fuels with electricity or natural gas has been launched in Beijing, Tianjin, and 26 other municipalities in northern China, aiming at solving severe ambient air pollution in the region. Quantitative analysis shows that the campaign can accelerate residential energy transition significantly, and if the planned target can be achieved, more than 60% of households are projected to remove solid fuels by 2021, compared with fewer than 20% without the campaign. Emissions of major air pollutants will be reduced substantially. With 60% substitution realized, emission of primary PM2.5 and contribution to ambient PM2.5 concentration in 2021 are projected to be 30% and 41% of those without the campaign. With 60% substitution, average indoor PM2.5 concentrations in living rooms in winter are projected to be reduced from 209 (190 to 230) μg/m3 to 125 (99 to 150) μg/m3 The population-weighted PM2.5 concentrations can be reduced from 140 μg/m3 in 2014 to 78 μg/m3 or 61 μg/m3 in 2021 given that 60% or 100% substitution can be accomplished. Although the original focus of the campaign was to address ambient air quality, exposure reduction comes more from improved indoor air quality because ∼90% of daily exposure of the rural population is attributable to indoor air pollution. Women benefit more than men.

The impacts of China's provincial energy policies on major air pollutants: A spatial econometric analysis

The production and consumption of energy is the predominant source of air pollution worldwide. Thus, governmental energy control policies may lead to large reductions in air pollutant emissions. Energy policies can be broadly categorized into two types based on their policy goals. First are emission reduction policies, identified as throttling measures, which aim to reduce emissions from the source; second are renewable energy policies, which are dedicated to the development and promotion of renewable energy. This paper employs a spatial econometric method to empirically test the effects of these two types of energy policies on China's emissions of major air pollutants, namely PM10, PM2.5, and SO2, using panel data from 27 provinces and four direct-controlled municipalities over the period from 2003 to 2016. The results offer evidence that provincial emission reduction policies have positive impacts on reduction of PM10, whereas provincial renewable energy policies have positive impacts on the reduction of SO2 and PM2.5. The results also show that energy policies in one province can influence emissions of pollutants in neighbouring provinces due to policy spillover effects. Several policy implications are made based on the research findings.

Carbon dioxide mitigation co-benefit analysis of energy-related measures in the Air Pollution Prevention and Control Action Plan in the Jing-Jin-Ji region of China

Abstract To improve air quality and protect public health, the State Council of China issued the National Air Pollution Prevention and Control Action Plan (‘the Action Plan’) in 2013. Specific measures were designed in the Action Plan to reduce emissions of atmospheric pollutants, with core contents in energy related measures. Implementing these measures would potentially have significant co-benefits on carbon dioxide (CO2) emissions. This study quantitatively analyzes the impacts of the different measures in the Action Plan on the emissions of major air pollutants of sulfur dioxide (SO2), nitrogen oxides (NOX), particulate matter (PM) and CO2 in the Jing-Jin-Ji (JJJ, i.e., Beijing-Tianjin-Hebei) region using the Greenhouse Gas and Air Pollution Interactions and Synergies model (GAINS)-China model. The results show that the Action Plan in JJJ would reduce 47.3 ± 0.8% of SO2, 32.5 ± 2.6% of NOx, 15.2 ± 0.2% of PM2.5, and 39.9 ± 5.3% CO2 emissions, compared to the emissions in 2012. PM2.5 emission reduction has the highest co-benefit for CO2 reduction in JJJ, and also in Tianjin and Hebei. In Beijing, NOx emission reduction has high co-benefit for CO2 reduction, when considering the relative degree of co-benefit. Among the different source sectors, industrial and residential sectors are identified to be the source sectors that contribute the most to the co-benefit of CO2 emission reduction in JJJ. The results suggest that implementing energy replacement in the industrial and residential sectors in JJJ can not only generate large amounts of air pollutants emission reduction, but also can lead to significant CO2 emission reduction.

Tracing Air Pollutant Emissions in China: Structural Decomposition and GVC Accounting

The depth and breadth of China’s participation in global value chains have an important impact on the emissions of air pollutants from the production side, consumption side, and trade implications in China’s industries. Based on the global value chain accounting framework, this paper examines the path of China’s major air pollutant emissions in production and consumption during 1995–2009 and structurally decomposes the factors affecting air pollutant emissions. The results show that, firstly, both the air pollutant emissions on the production side and the air pollution emissions on the consumption side have increased significantly, and the production-side emissions have been higher than the consumption-side emissions. Secondly, the export of intermediate products shows a trend of “high pollution”, and this trend was more obvious after China’s accession to the world trade organization (WTO). Thirdly, the expansion of economic growth was the most important factor in the rapid emission of air pollutants in China and the reduction of pollution efficiency in Chinese industries depends on the increase in service inputs.

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

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.

Permitted emissions of major air pollutants from coal-fired power plants in China based on best available control technology

Based on the activity level and technical information of coal-fired power-generating units (CFPGU) obtained in China from 2011 to 2015, we, 1) analyzed the time and spatial distribution of SO2 and NOx emission performance of CFPGUs in China; 2) studied the impact of installed capacity, sulfur content of coal combustion, and unit operation starting time on CFPGUs’ pollutant emission performance; and 3) proposed the SO2 and NOx emission performance standards for coal-fired power plants based on the best available control technology. Our results show that: 1) the larger the capacity of a CFPGU, the higher the control level and the faster the improvement; 2) the CFPGUs in the developed eastern regions had significantly lower SO2 and NOx emission performance values than those in other provinces due to better economic and technological development and higher environmental management levels; 3) the SO2 and NOx emission performance of the Chinese thermal power industry was significantly affected by the single-unit capacity, coal sulfur content, and unit operation starting time; and 4) based on the achievability analysis of best available pollution control technology, we believe that the CFPGUs’ SO2 emission performance reference values should be 0.34 g/kWh for active units in general areas, 0.8 g/kWh for active units in high-sulfur coal areas, and 0.13 g/kWh for newly built units and active units in key areas. In addition, the NOx emission performance reference values should be 0.35 g/kWh for active units in general areas and 0.175 g/kWh for new units and active units in key areas.

Quantifying the rural residential energy transition in China from 1992 to 2012 through a representative national survey

Rural household energy use for cooking and heating is an important source of air pollutants in China, as it affects both human health and climate change. However, the magnitude of rural household energy use, especially during the recent rapid socioeconomic transition period, has not been well quantified. Here, we present first-hand nationwide data from a 34,489-household energy-mix survey and a 1,670-household fuel-weighing campaign. We found that the consumption of wood and crop residues in rural China decreased by 63% and 51%, respectively, from 1992 to 2012, and these decreases were much greater than the 15% and 8%, respectively, reported by the International Energy Agency and Food and Agriculture Organization. The rapid residential energy transition over these two decades was primarily driven by the rapid socioeconomic development. One important implication of this transition is the significant reduction in the emissions of major air pollutants, especially incomplete combustion products leading to significant impacts on health and climate. Use of wood and crop residue for cooking and heating in rural China is a significant source of carbon emissions and air pollution. Using a survey of more than 34,000 households, researchers show that between 1992 and 2012 usage of these fuels decreased by much more than previous estimates, due primarily to rising incomes.