This article analyzed the control progress and current status of air quality,identified the major air pollution issues and challenges in future,proposed the long-term air pollution control ...targets,and suggested the options for better air quality in China.With the continuing growth of economy in the next 10–15 years,China will face a more severe situation of energy consumption,electricity generation and vehicle population leading to increase in multiple pollutant emissions.Controlling regional air pollution especially fine particles and ozone,as well as lowering carbon emissions from fossil fuel consumption will be a big challenge for the country.To protect public health and the eco-system,the ambient air quality in all Chinese cities shall attain the national ambient air quality standards （NAAQS） and ambient air quality guideline values set by the World Health Organization （WHO）.To achieve the air quality targets,the emissions of SO 2,NOx,PM 10,and volatile organic compounds （VOC） should decrease by 60%,40%,50%,and 40%,respectively,on the basis of that in 2005.A comprehensive control policy focusing on multiple pollutants and emission sources at both the local and regional levels was proposed to mitigate the regional air pollution issue in China.The options include development of clean energy resources,promotion of clean and efficient coal use,enhancement of vehicle pollution control,implementation of synchronous control of multiple pollutants including SO 2,NOx,VOC,and PM emissions,joint prevention and control of regional air pollution,and application of climate friendly air pollution control measures.
Background: In 2013, China released the Air Pollution Prevention and Control Action Plan (Action Plan), which set the roadmap for national air pollution control actions for the period of 2013 to ...2017. A decrease in the fine particulate matter with aerodynamic diameter ≤ 2.5μ m (PM 2.5 ) concentration may lead to a substantial benefit for human health. Objective: We aimed to quantify the relative contributions four factors: emission reductions, changed meteorology, population growth, and a change in baseline mortality rates to the reducedPM 2.5 -related mortality (PM 2.5 -mortality) during the 2013–2017 period and evaluate the importance of emission controls for human health protection in China. Methods: The integrated exposure–response function was adopted to estimate the chronic health effects ofPM 2.5 . The annualPM 2.5 concentrations were estimated from chemical transport model simulations combined with surface observations for 2013 and 2017. Relative contributions toPM 2.5 -mortality from emission reductions and the three factors were individually quantified through scenario analysis. Results: The estimated totalPM 2.5 -mortality in China was 1.389 million 95% confidence interval (CI): 1.005 million, 1.631 million in 2013 but was substantially reduced to 1.102 million (95% CI: 0.755 million, 1.337 million) in 2017. Emission controls contributed 88.7% to this reduction inPM 2.5 -mortality, while changed meteorology, the change in baseline mortality rates, and population growth during 2013–2017 contributed 9.6, 3.8, and − 2.2 % , respectively. Conclusions: The implementation of the Action Plan has significantly reduced thePM 2.5 concentration in regions of China where population density is high, dominating the decline inPM 2.5 -mortality during 2013–2017. However, the health burden ofPM 2.5 pollution in China is still extremely high compared with that in other developed countries. An aggressive air pollution control strategy should be implemented in densely populated areas to further reduce the health burden.
In order to cope with heavy haze pollution in China, the Air Pollution Prevention and Control Action Plan including phased goals of the fine particulate matter (PM2.5) was issued in 2013. In this ...study, China's emission inventories in the baseline 2012 and the future scenarios of 2017 and 2020 have been developed based on this Action Plan. Beijing-Tianjin-Hebei (Jing-Jin-Ji) region, one of the most polluted regions in China, was taken as a case to assess the impact of phased emission control measures on PM2.5 concentration reduction using WRF-CMAQ model system. With the implementation of the Action Plan, the emissions of sulfur dioxide (SO2), nitrogen oxides (NOX), PM2.5, non-methane volatile organic compound (NMVOC), and ammonia (NH3) in 2017 will decrease by36%, 31%, 30%,12%, and −10% from the 2012 levels in Jing-Jin-Ji, respectively. In 2020, the emissions of SO2, NOX, PM2.5, NMVOC, and NH3 will decrease by 40%, 44%, 40%, 22%, and −3% from the 2012 levels in Jing-Jin-Ji, respectively. Consequently, the ambient annual PM2.5 concentration under the scenarios of 2017 and 2020 will be 28.3% and 37.8% lower than those in 2012, respectively. The Action Plan provided an effective approach to alleviate PM2.5 pollution level in Jing-Jin-Ji region. However, emission control of NMVOC and NH3 should be paid more attention and be strengthened in future. Meanwhile, emission control of NOx, SO2, NH3 and NMVOC synergistically are highly needed in the future because multiple pollutants impact on PM2.5 and O3 concentrations nonlinearly.
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•Multiple-pollutants emission inventory for 2012 and two scenarios for 2017 and 2020 are developed based on the Action Plan.•WRF-CMAQ model system is used to simulate PM2.5 concentrations in Jing-Jin-Ji region during 2012-2020.•PM2.5 concentrations under the scenarios of 2017 and 2020 will be 28.3% and 37.8% lower than those in 2012, respectively.•NMVOC and NH3 should be strictly controlled in the future.
Volatile organic compounds （VOCs） are major precursors for ozone and secondary organic aerosol （SOA）, both of which greatly harm human health and significantly affect the Earth＇s climate. We ...simultaneously estimated ozone and SOA formation from anthropogenic VOCs emissions in China by employing photochemical ozone creation potential （POCP） values and SOA yields. We gave special attention to large molecular species and adopted the SOA yield curves from latest smog chamber experiments. The estimation shows that alkylbenzenes are greatest contributors to both ozone and SOA formation （36.0% and 51.6%, respectively）, while toluene and xylenes are largest contributing individual VOCs. Industry solvent use, industry process and domestic combustion are three sectors with the largest contributions to both ozone （24.7%, 23.0% and 17.8%, respectively） and SOA （22.9%, 34.6% and 19.6%, respectively） formation. In terms of the formation potential per unit VOCs emission, ozone is sensitive to open biomass burning, transportation, and domestic solvent use, and SOA is sensitive to industry process, domestic solvent use, and domestic combustion. Biomass stoves, paint application in industrial protection and buildings, adhesives application are key individual sources to ozone and SOA formation, whether measured by total contribution or contribution per unit VOCs emission. The results imply that current VOCs control policies should be extended to cover most important industrial sources, and the control measures for biomass stoves should be tightened. Finally, discrepant VOCs control policies should be implemented in different regions based on their ozone/aerosol concentration levels and dominant emission sources for ozone and SOA formation potential.
Beijing, the capital of China, has experienced rapid industrialization, urbanization and motorization in recent decades. Consequently, air pollution in Beijing, especially fine particulate matter ...(PM2.5) pollution, has gradually become a severe environmental issue, due to the continuing growth in energy consumption and the resulting multiple pollutant emissions. In response to the increasingly serious PM2.5 pollution, Beijing's government implemented a series of policies, measures and regulations on air pollution prevention and control and took some concrete actions to improve air quality. In this paper, firstly, we summarize China's ambient air quality standards, China's policies and regulations on air pollution prevention and control. Secondly, we illustrate historical evolution and current status of air pollution in Beijing. Finally, we introduce control measures and actions in Beijing and its surrounding areas. The paper aims to help environmental scientists and policy makers around the world understand the past and current air pollution in Beijing and control strategies and actions taken by Beijing's government. Display omitted
Water-soluble inorganic ions (WSI), a major component of PM2.5, often increased rapidly during the haze event in Beijing. Sulfate (SO42−), Nitrate (NO3−), and Ammonium (NH4+) are three main ...components of WSI. Since year 2015, sulfate concentrations in PM2.5 has gradually decreased owing to the effective control of SO2 emissions. However, the contribution of nitrate to PM2.5 has significantly increased during haze events in Beijing at the same time. In this study, a highly time-resolved online analyzer (Monitor for Aerosols and Gases, MARGA) was employed to measure the WSI in PM2.5 in Beijing from 5 February to 15 November 2017. Three typical haze events during this sampling period were investigated. During heavy pollution episodes in winter, nitrate concentrations increased from 7.5 μg/m3 to 45.6 μg/m3 (45.0% of WSI), while sulfate increased from 4.2 μg/m3 to 20.1 μg/m3 (19.8% of WSI). This indicated that nitrate is more important than sulfate as a driver for the growth of PM2.5 during the period of heavy air pollution in winter. Nitrate also dominates the increase of WSI in the pollution episodes in autumn, with an average concentration of 52.5 μg/m3, and contributed up to 67% of WSI. The average concentration ratio of NH4+ to SO42− was higher in autumn (1.02) than that in summer (0.74) and close to that in winter (1.00). This is mainly because the emission control of coal combustion in Beijing and surrounding areas results in an NH3-rich and SO2-lean atmosphere, which promoted the formation of ammonium nitrate. Our study indicates that nitrate has become the most important component of WSI in PM2.5 and is driving the rapid growth of PM2.5 concentrations during heavy pollution episodes in Beijing. Therefore, more efforts shall be made to reduce the nitrogen oxide and ammonia emissions in Beijing and surrounding areas.
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•Nitrate become the main component of PM2.5 than sulfate during the haze events in Beijing.•High NOx emission, low temperature and low aerosol acidity are the key factors to promote nitrate formation in Beijing.•Molar ratio of NH4+ to SO42- increased from 1.5 (before 2013) to 3.33 (2017) due to ammonia-rich atmosphere in Beijing.
The removal of NOₓ by catalytic technology at low temperatures (100–300°C) is significant for flue gas of industry and exhaust gas of diesel engine; however, to develop the low-temperature catalyst ...(LTC) for selective catalytic reduction of NOₓ with ammonia (NH₃-SCR) is still a challenge especially at temperature below 200°C. This study reviews two types of LTC, the metal oxide catalyst and metal exchanged zeolite catalyst. The performances of Mn-based metal oxide with and without supports have been attempted to correlate with preparation method, precursor, and various supports. The role of manganese oxides with different phases as the most effective low temperature active component and the limitation of stability in the presence of H₂O and SO₂ are discussed. Fe, Cu exchanged zeolites as potential real application catalysts in diesel engine have been investigated for NH₃-SCR of NOₓ in the past decades, the activity, selectivity and thermal stability related to types of metal, and zeolite, and reaction conditions are reviewed. The research progress in active sites and reaction mechanisms of Mn-based catalyst and Fe–zeolite catalysts are described and compared. Finally, future research directions in the developing LTC for removal of NOₓ are proposed.
PM2.5 and its major chemical compositions were sampled and analyzed in January, April, July and October of 2014 at Beijing (BJ), Tianjin (TJ), Langfang (LF) and Baoding (BD) in order to probe the ...temporal and spatial characteristics as well as source apportionment of PM2.5 in the Beijing-Tianjin-Hebei (BTH) region. The results showed that PM2.5 pollution was severe in the BTH region. The average annual concentrations of PM2.5 at four sampling sites were in the range of 126–180 μg/m3, with more than 95% of sampling days exceeding 35 μg/m3, the limit ceiling of average annual concentration of PM2.5 regulated in the Chinese National Ambient Air Quality Standards (GB3095-2012). Additionally, concentrations of PM2.5 and its major chemical species were seasonally dependent and demonstrated spatially similar variation characteristics in the BTH region. Concentration of toxic heavy metals, such as As, Cd, Cr, Cu, Mn, Ni, Pb, Sb, Se, and Zn, were higher in winter and autumn. Secondary inorganic ions (SO42−, NO3−, and NH4+) were the three-major water-soluble inorganic ions (WSIIs) of PM2.5 and their mass ratios to PM2.5 were higher in summer and autumn. The organic carbon (OC) and elemental carbon (EC) concentrations were lower in spring and summer than in autumn and winter. Five factors were selected in Positive Matrix Factorization (PMF) model analysis, and the results showed that PM2.5 pollution was dominated by vehicle emissions in Beijing, combustion emissions including coal burning and biomass combustion in Langfang and Baoding, and soil and construction dust emissions in Tianjin, respectively. The air mass that were derived from the south and southeast local areas around BTH regions reflected the features of short-distant and small-scale air transport. Shandong, Henan, and Hebei were identified the major potential sources-areas of secondary aerosol emissions to PM2.5.
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•We present the temp-spatial PM2.5 variations at four cities in BTH region of China.•PM2.5 concentrations and its species show spatially similar variation in BTH region.•PMF results indicate PM2.5 pollution is dominated by vehicle emissions in Beijing.•Coal combustion plays a significant contribution on PM2.5 in LangFang and Baoding.•Soil and construction dust constitute most important components of PM2.5 in TianJin.
PM2.5 mass and its major chemical composition in the BTH region were seasonally dependent and demonstrated spatially similar variation characteristics. PMF results indicated that PM2.5 was dominated by vehicle emissions in Beijing, coal and biomass combustion emissions in Langfang and Baoding, and soil and construction dust emissions in Tianjin, respectively.
Mercury pollution control has become a global goal. The accurate estimate of long-term mercury emissions in China is critical to evaluate the global mercury budget and the emission reduction ...potentials. In this study, we used a technology-based approach to compile a consistent series of China's atmospheric mercury emissions at provincial level from 1978 to 2014. China totally emitted 13 294 t of anthropogenic mercury to air during 1978-2014, in which gaseous elemental mercury, gaseous oxidized mercury, and particulate-bound mercury accounted for 58.2%, 37.1%, and 4.7%, respectively. The mercury removed during this period were 2085 t in coal-fired power plants (counting 49% of mercury input), 7259 t in Zn smelting (79%), 771 t in coal-fired industrial boilers (25%), and 658 t in cement production plants (27%), respectively. Annual mercury emissions increased from 147 t in 1978 to 530 t in 2014. Both sectoral and spatial emissions of atmospheric mercury experienced significant changes. The largest mercury emission source evolved from coal-fired industrial boilers before 1998, to zinc smelting during 1999-2004, coal-fired power plants during 2005-2008, finally to cement production after 2009. Coal-fired industrial boilers and cement production have become critical hotpots for China's mercury pollution control.
In this study, a systematic overview of inhalable particulate matter (PM10) pollution in China was conducted based on the dataset from national monitoring network from 2001 to 2011. The long-term ...trend, spatial and temporal distributions, and health impacts of PM10 pollution were evaluated. It was found that the annual PM10 concentration decreased from 116.0 μg m−3 in 2001 to 85.3 μg m−3 in 2011. The days with PM10 concentration above the new Chinese ambient air quality standard dropped from 66 (18%) in 2001 to 28 (7.8%) in 2011, while the days exceeding the World Health Organization (WHO) guideline decreased from 294 (80.5%) in 2001 to 250 (68.5%) in 2011. PM10 pollution in northern China is much worse than that in southern China. Six of nine most polluted cities (>110 μg m−3) are in the north, while six cleanest cities (<50 μg m−3) are all in the south. The seasonal average PM10 concentrations in 2001–2011 for all cities are 104.4 μg m−3 (spring), 75.3 μg m−3 (summer), 94.7 μg m−3 (autumn), and 118.4 μg m−3 (winter), respectively, indicating that winter and spring are the most polluted seasons. Different health endpoints due to PM10 pollution show similar trends. Taking premature mortality between 2001 and 2011 as an example, the ratio of deaths due to PM10 pollution to all causes of deaths dropped from 13.5% to 11.6% and 511,000 deaths are avoided due to the concentration reduction, though the absolute damage number due to PM10 pollution increased from 418,000 to 514,000 because of increasing urban population. These results indicate that PM10 pollution in China has been eased significantly over the last decade, mainly due to the application of emission control measures. However, the PM10 concentration remains at a high level comparing with the WHO guideline and its health impacts are still significant.
► Characteristics and health impacts of PM10 pollution in China were evaluated. ► PM10 pollution in China has been reduced during the last decade. ► PM pollution (especially fine particles) is still a severe environmental problem. ► Great health benefit is achieved due to PM10 reduction. ► The absolute damage cases are increasing due to the increase in urban population.
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