How well have China's recent five-year plans been implemented for energy conservation and air pollution control?

The Global Environmental Impacts of China's Accession to the WTO: A 20-Year Review

Robust empirical assessments of the long-term cumulative global effects of free trade and economic globalization on the environment are limited. This account fills this gap by constructing a dynamic computable general equilibrium model to estimate the environmental effects of a milestone in the recent history of trade liberalization: China's 20-year World Trade Organization (WTO) accession. The modeling shows that China's accession could have resulted in an increase in the global cumulative greenhouse gases (GHGs), sulfur dioxide (SO2), and nitrogen oxide (NOx) emissions by roughly 14,000 Mt CO2-eq, 64 Mt, and 46 Mt, respectively. The global production scale effect contributed to most of these estimated increases. The regional total output composition effect also caused higher emissions. Meanwhile, the sectoral output composition effect helped reduce total emissions to a limited extent. Fortunately, a package of emission abatement measures led to a decrease in emission factors and a drop in the global cumulative emissions of GHGs, SO2, and NOx. The findings suggest that to enjoy the free trade and economic globalization benefits and minimize the induced emission increases, it is vitally important to systemically reduce emissions across the entire economy and nurture a low-carbon trade regime.

Does new energy demonstration city policy curb air pollution? Evidence from Chinese cities

China has embarked on realizing a green-oriented energy structure transition with a series of policy tools. In 2014, the National Energy Administration launched a new energy demonstration city (NEDC) policy, but its effect on air pollution mitigation has not been fully examined. By employing the Difference-in-difference strategy, this study examines the effect of the NEDC policy on air pollution mitigation with Chinese prefecture-level city data. The results reveal that the NEDC policy can significantly lead to a 0.13-unit drop in SO2 emissions. The NEDC policy curbs pollution by stimulating green investments, promoting green technology innovation, advancing resource allocation efficiency, and reducing energy consumption. The effect of the NEDC policy appears to be heterogeneous under different conditions. Furthermore, this phenomenon is more conspicuous in prefectures led by older officials, where the age incentives nearing the promotion golden age threshold amplify the effects of air pollution mitigation, while those nearing retirement years exacerbate such effects. Notably, the interaction effect between environmental regulations and the NEDC policy on air pollution mitigation is elucidated. Moreover, positive spatial spillover effects extending to neighboring regions are identified, underscoring the imperative of regional collaboration and technological diffusion. Based on the findings above, several policy implications are proposed.

Can regional joint prevention and control of atmospheric reduce border pollution? Evidence from China's 12th Five-Year Plan on air pollution

Border pollution is usually a difficult problem in environmental governance. Based on the data at the county level in China from 2005 to 2019, this study takes the 12th Five-Year Plan (FYP) for atmospheric pollution as a policy shock, and uses the difference-in-differences (DID) method to explore the impact of regional joint prevention and control (JPC) of atmospheric pollution policy on air pollution of the border regions. Empirical results show that: (1) After implementing the JPC of atmospheric pollution policy, the PM_2.5 concentration in the border regions is reduced by 3.5%. (2) The mechanism analysis shows that there is a spillover effect in the governing behaviors of local governments. In the border areas under low economic growth pressure and high environmental protection pressure, the reduction effect of the JPC of atmospheric pollution policy is more significant on the PM_2.5 concentration of the border regions. The research conclusions have new insights into the role and effect of macro-regional environmental JPC policy and border pollution control, and provide practical guidance for social green governance.

Restricted Anthropogenic Activities and Improved Urban Air Quality in China: Evidence from Real-Time and Remotely Sensed Datasets Using Air Quality Zonal Modeling

The study aims to examine the major atmospheric air pollutants such as NO2, CO, O3, PM2.5, PM10, and SO2 to assess the overall air quality using air quality zonal modeling of 15 major cities of China before and after the COVID-19 pandemic period. The spatio-temporal changes in NO2 and other atmospheric pollutants exhibited enormous reduction due to the imposition of a nationwide lockdown. The present study used a 10-day as well as 60-day tropospheric column time-average map of NO2 with spatial resolution 0.25 × 0.25° obtained from the Global Modeling and Assimilation Office, NASA. The air quality zonal model was employed to assess the total NO2 load and its change during the pandemic period for each specific region. Ground surface monitoring data for CO, NO2, O3, PM10, PM2.5, and SO2 including Air Quality Index (AQI) were collected from the Ministry of Environmental Protection of China (MEPC). The results from both datasets demonstrated that NO2 has drastically dropped in all the major cities across China. The concentration of CO, PM10, PM2.5, and SO2 demonstrated a decreasing trend whereas the concentration of O3 increased substantially in all cities after the lockdown effect as observed from real-time monitoring data. Because of the complete shutdown of all industrial activities and vehicular movements, the atmosphere experienced a lower concentration of major pollutants that improves the overall air quality. The regulation of anthropogenic activities due to the COVID-19 pandemic has not only contained the spread of the virus but also facilitated the improvement of the overall air quality. Guangzhou (43%), Harbin (42%), Jinan (33%), and Chengdu (32%) have experienced maximum air quality improving rates, whereas Anshan (7%), Lanzhou (17%), and Xian (25%) exhibited less improved AQI among 15 cities of China during the study period. The government needs to establish an environmental policy framework involving central, provincial, and local governments with stringent laws for environmental protection.

Effects of acid rain on plant growth: A meta-analysis

Anthropogenic driven acid gases emission has caused acid rain in many regions globally. Although efforts have been made to assess the effects of acid rain on terrestrial ecosystems, a systematic assessment of growth-related traits across plant aboveground and belowground is lacking. Hence, we performed a phylogenetically controlled meta-analysis of 755 observations from 69 independent studies to quantify the effects of acid rain on six growth-related traits of plant. We estimated the inhibitory effects of acid rain on plant growth in general and found that aboveground and belowground plant parts responded differently. The acidity of acid rain and acid rain interval had direct modulation effects on plant growth. We also found that there were interactions between acid rain pH and other acid rain characteristics (i.e., acid rain interval, mole ratio of S:N, and acid rain rate) and experimental characteristics (i.e., initial soil pH and plant exposure part), indicating that there were pH-dependent interaction patterns. Thus, an effective approach to evaluate and predict the effects of acid rain on plant growth is to fully consider the direct effects of acid rain pH and the interactions between acid rain pH and other factors.

Air pollution control efficacy and health impacts: A global observational study from 2000 to 2016

Particulate matter with aerodynamic diameter ≤2.5 μm (PM_2.5) concentrations vary between countries with similar carbon dioxide (CO₂) emissions, which can be partially explained by differences in air pollution control efficacy. However, no indicator of air pollution control efficacy has yet been developed. We aimed to develop such an indicator, and to evaluate its global and temporal distribution and its association with country-level health metrics. A novel indicator, ambient population-weighted average PM_2.5 concentration per unit per capita CO₂ emission (PM_2.5/CO₂), was developed to assess country-specific air pollution control efficacy (abbreviated as APCI). We estimated and mapped the global average distribution of APCI and its changes during 2000-2016 across 196 countries. Pearson correlation coefficients and Generalized Additive Mixed Model (GAMM) were used to evaluate the relationship between APCI and health metrics. APCI varied by country with an inverse association with economic development. APCI showed an almost stable trend globally from 2000 to 2016, with the low-income groups increased and several countries (China, India, Bangladesh) decreased. The Pearson correlation coefficients between APCI and life expectancy at birth (LE), infant-mortality rate (IMR), under-five year of age mortality rate (U5MR) and logarithm of per capita GDP (LPGDP) were -0.57, 0.65, 0.66, -0.59 respectively (all P values < 0.001). APCI could explain international variation of LE, IMR and U5MR. The associations between APCI and LE, IMR, U5MR were independent of per capita GDP and climatic factors. We consider APCI to be a good indicator for air pollution control efficacy given its relation to important population health indicators. Our findings provide a new metric to interpret health inequity across the globe from the point of climate change and air pollution control efficacy.

Morphological, Physiological and Photophysiological Responses of Critically Endangered Acer catalpifolium to Acid Stress

Acid rain deposition (AR) has long-lasting implications for the community stability and biodiversity conservation in southwest China. Acer catalpifolium is a critically endangered species in the rain zone of Western China where AR occurs frequently. To understand the effects of AR on the morphology and physiology of A. catalpifolium, we conducted an acid stress simulation experiment for 1.5 years. The morphological, physiological, and photosynthetic responses of A. catalpifolium to the acidity, composition, and deposition pattern of acid stress was observed. The results showed that simulated acid stress can promote the growth of A. catalpifolium via the soil application mode. The growth improvement of A. catalpifolium under nitric-balanced acid rain via the soil application mode was greater than that of sulfuric-dominated acid rain via the soil application mode. On the contrary, the growth of A. catalpifolium was significantly inhibited by acid stress and the inhibition increased with the acidity of acid stress applied via leaf spraying. The inhibitory impacts of nitric-balanced acid rain via the leaf spraying of A. catalpifolium were greater than that of sulfur-dominant acid rain via leaf spraying. The observations presented in this work can be utilized for considering potential population restoration plans for A. catalpifolium, as well as the forests in southwest China.

Prospects for ozone pollution control in China: An epidemiological perspective

Severe surface ozone pollution has become widespread in China. To protect public health, Chinese scientific communities and government agencies have striven to mitigate ozone pollution. However, makers of pollution mitigation policies rarely consider epidemiological research, and communication between epidemiological researchers and the government is poor. Therefore, this article reviews the current mitigation policies and the National Ambient Air Quality Standard (NAAQS) for ozone from an epidemiological perspective and proposes recommendations for researchers and policy makers on the basis of epidemiological evidence. We review current nationwide ozone control measures for mitigating ozone pollution from four dimensions: the integration of ozone and particulate matter control, ozone precursors control, ozone control in different seasons, and regional cooperation on the prevention of ozone pollution. In addition, we present environmental and epidemiological evidence and propose recommendations and discuss relevant ozone metrics and the criteria values of the NAAQS. We finally conclude that the disease burden attributable to ozone exposure in China may be underestimated and that the epidemiological research regarding the health effects of integrating ozone and particulate matter control is insufficient. Furthermore, atmospheric volatile organic compounds are severely detrimental to health, and related control policies are urgently required in China. We recommend a greater focus on winter ozone pollution and conclude that the health benefits of regional cooperation on ozone control and prevention are salient. We argue that daily average ozone concentration may be a more biologically relevant ozone metric than those currently used by the NAAQS, and accumulating epidemiological evidence supports revision of the standards. This review provides new insight for ozone mitigation policies and related epidemiological studies in China.

CO2 and Air Pollutants Emissions under Different Scenarios Predicted by a Regional Energy Consumption Modeling System for Shanghai, China

About 75% energy demand and emissions all concentrate in urban areas, especially in the metropolises, placing a heavy burden on both the energy supply system and the environment system. To explore low emission pathways and provide policy recommendations for the Shanghai energy system and the environmental system to reach the carbon dioxide (CO2) peak by 2030 and attain emission reduction targets for local air pollutants (LAPs), a regional energy–environment optimization model was developed in this study, considering system costs, socio-economic development and technology. To verify the reliability of the model simulation and evaluate the model risk, a historical scenario was defined to calculate the emissions for 2004–2014, and the data were compared with the bottom-up emission inventory results. By considering four scenarios, we simulated the energy consumption and emissions in the period of 2020–2030 from the perspective of energy policies, economic measures and technology updates. We found that CO2 emissions might exceed the amount of 250 million tons by the end of 2020 under the current policy, and carbon tax with a price of 40 CNY per ton of carbon dioxide is an imperative measure to lower carbon emissions. Under the constraints, the emissions amount of SO2, NOx, PM10, and PM2.5 will be reduced by 95.3–180.8, 207.8–357.1, 149.4–274.5, and 59.5–119.8 Kt in 2030, respectively.

Comparative effects of the recovery from sulfuric and nitric acid rain on the soil enzyme activities and metabolic functions of soil microbial communities

Acid rain (AR) is a serious issue in China, particularly in the Yangtze River Delta region where the economy has undergone rapid development. Over the last few years, the composition of acid rain in the Yangtze River Delta region has gradually changed from sulfuric acid rain (SAR) to nitric acid rain (NAR) due to controls on SO₂ emissions, but increased NO_x emissions. These changes have made ecosystems more complex. For this study, we halted AR treatments in Quercus acutissima forest plots that had received simulated AR for one year and monitored them from the following February to November. We investigated their soil resident enzyme and microbial metabolic activities, as well as community functional diversity. The results revealed that AR treatments negatively affected both the soil microbial activity and soil microbial community functional diversity; however, both managed to recover over time, once the AR treatments were stopped. During the AR treatment and recovery periods, four main categories (carbohydrates, carboxylic acids, amino acids, and polymers) were dominantly utilized. The utilization of pyruvic acid, which was affected by the AR treatments, as well as d-mannitol and tween 80, accounted for changes in the peak values of the C substrate groups during the AR treatment recovery period. Finally, changes in the activities of soil enzymes recorded following AR recovery, were closely related to the utilization of six C substrate groups. Our results suggested that the recovery of soils following the cessation of NAR stress was more rapid than from SAR. Further, that short-term NAR could be easily treated during the transformation from SAR to NAR in the Yangtze River Delta region. These results might also enrich the basic data relating to post-AR treatments on the soil environment, while having significance toward guiding further studies on the recovery of ecosystems from AR.

Decoupling and decomposition analysis of industrial sulfur dioxide emissions from the industrial economy in 30 Chinese provinces

As one of the largest emitters of sulfur dioxide (SO₂), China has faced increasing pressure to achieve sustainable development. This study investigates the decoupling relationship between industrial SO₂ emissions and the industrial economy in China during 1996-2015. According to the decoupling results, the study period is divided into four stages: 1996-2001, 2001-2006, 2006-2010, and 2010-2015. These four stages are closely aligned with the major adjustments of the national socio-economic policies. Then, the logarithmic mean Divisia index (LMDI) decomposition method is used to analyze the driving factors of industrial SO₂ emissions. The results demonstrate that the SO₂ generation intensity and SO₂ abatement are the major contributors to reducing industrial SO₂ emissions, while the economic activity effect is the primary inhibitory factor. Moreover, the provincial results show that most provinces with weak decoupling state since 2006 are located in less developed provinces with energy-intensive industries. Besides, the economic structure and SO₂ generation intensity show negative contributions to reducing industrial SO₂ emissions in some of these regions. Based on the results, the attention should be focused on cleaner production to reduce industrial SO₂ emissions further, and environmental policies should be tailored to local conditions.

Growth and physiological response of an endangered tree, Horsfieldia hainanensis merr., to simulated sulfuric and nitric acid rain in southern China

As nitrogen deposition increases, acid rain is gradually shifting from sulfuric acid rain (SAR) to nitric acid rain (NAR). Acid rain can severely affect plant growth, damage ecosystems, and reduce biodiversity. Thus, a shift in acid rain type presents another challenge to the conservation of endangered plant species. We investigated the effect of three acid rain types (SAR, mixed acid rain [MAR], and NAR) and pH on the growth of an endangered Chinese endemic tree, Horsfieldia hainanensis Merr., using simulated rain in a greenhouse environment. Over nine months, growth indices, chlorophyll content, antioxidant enzyme activity, malondialdehyde content, and chlorophyll fluorescence parameters were investigated for treated and control saplings. The results indicated that at a pH of 5.6, H. hainanensis could adapt to SAR and MAR, but NAR inhibited below-ground growth. At a pH of 2.5 and 4.0, SAR inhibited stem and leaf biomass accumulation, whereas NAR inhibited root biomass accumulation and altered root morphology. MAR had intermediary effects between those of SAR and NAR. Adverse effects on leaf physiology were reduced as the rain type shifted from SAR to NAR; however, roots were increasingly adversely affected. Our results suggest that conservation efforts for H. hainanensis should shift from an above-ground to a below-ground focus as acid rain transitions toward NAR.

The asymmetric effect of air quality on cross-industries' stock returns: evidence from China

This paper offers a perspective for the link between air quality and stock returns in China through quantile Granger causality test. Compared to previous studies, the study makes the following innovations. Given the Chinese government plays an important role in economic development, its industrial policies are regarded as a new indispensable supplement of analysis framework apart from investor mood. Next, due to different reflections from cross-industries for different AQ levels, the industry heterogeneity is further considered. Also, nine industries are chosen as a sample, including environmental protection, wind power equipment, steel, photovoltaic equipment, thermal power, tourism, coal, medical service, and medical equipment. Besides, the quantile Granger causality test is robust to misspecification errors when detecting the potential dependence structure between the variables of air quality and stock returns. The empirical results show that the causal link exists in all industries, except medical service. Meanwhile, this impact presents asymmetrical features that when air quality is unhealthy, it has an influence on stock returns of the remaining eight industries. It can be explained by increasing cortisol level, more stringent environmental protection, and industrial policies. These conclusions have essential implications for market participants due to the fact that air quality generates various influences on the stock market. That is why a sustainable environmental design, strict regulatory framework, and special monitoring activities should be highly regarded in China.

Responses of forest ecosystems to increasing N deposition in China: A critical review

China has been experiencing a rapid increase in nitrogen (N) deposition due to intensified anthropogenic N emissions since the late 1970s. By synthesizing experimental and observational data taken from literature, we reviewed the responses of China's forests to increasing N deposition over time, with a focus on soil biogeochemical properties and acidification, plant nutrient stoichiometry, understory biodiversity, forest growth, and carbon (C) sequestration. Nitrogen deposition generally increased soil N availability and soil N leaching and decreased soil pH in China's forests. Consequently, microbial biomass C and microbial biomass N were both decreased, especially in subtropical forests. Nitrogen deposition increased the leaf N concentration and phosphorus resorption efficiency, which might induce nutrient imbalances in the forest ecosystems. Although experimental N addition might not affect plant species richness in the overstorey, it did significantly alter species composition of understory plants. Increased N stimulated tree growth in temperate forests, but this effect was weak in subtropical and tropical forests. Soil respiration in temperate forests was non-linearly responsive to N additions, with an increase at dosages of <60 kg N ha^-1 yr^-1 and a decrease at dosages of >60 kg N ha^-1 yr^-1. However, it was consistently decreased by increased N inputs in subtropical and tropical forests. In light of future trends in the composition (e.g., reduced N vs. oxidized N) and the loads of N deposition in China, further research on the effects of N deposition on forest ecosystems will have critical implications for the management strategies of China's forests.

A database of annual atmospheric acid and nutrient deposition to China's forests

Anthropogenic emissions have substantially altered atmospheric acid and nutrient deposition in China. Understanding the status and characteristics of acid and nutrient deposition to China’s forests is crucial to assess the consequent impacts, and to better guide forest management options. Based on a comprehensive literature review, here I present an updated database for annual acid and nutrient deposition during the period 1991-2015 in China’s forests (CFAND 2.0). The database includes information from 56 forested sites on the water fluxes of bulk precipitation and throughfall, the concentrations of H⁺ (pH), dissolved inorganic nitrogen (N) (NH₄⁺ and NO₃⁻), sulfur (S), dissolved phosphorus (P), potassium (K⁺), calcium (Ca²⁺) and magnesium (Mg²⁺) in bulk precipitation and throughfall, and the fluxes of dissolved inorganic N, S, dissolved P, K⁺, Ca²⁺ and Mg²⁺ in bulk deposition and throughfall. This database will help to understand the spatial patterns of acid and nutrient deposition, validate modelling results of acid and nutrient deposition and assess the ecological effects of acid and nutrient deposition in China’s forests.

Chinese National Air Protection Policy Development: A Policy Network Theory Analysis

Given its wide involvement in and recognition by international organizations, China has signed many international agreements and negotiations. This study verified how and the extent to which changes in exogenous factors (e.g., international agreements and negotiations) affect Chinese governmental air protection policy development. Previous studies on policy network theory have demonstrated that exogenous factors affected the development of domestic policies significantly, while in this study little evidence was found to demonstrate the influence of exogenous factors on changes in Chinese policy. Rather, internal factors have played an important role in both its development and transformation. These findings differ from study results on wealthy countries and other developing districts. This study then explores the causes of substandard policy outcomes. To probe this further, policy network theory is applied to explain the gap between the guiding principle of central government's policies and local implementation in actual practice. By analyzing the strategies of policy actors and specific rules in current Chinese context, the associated limitations and obstacles in the process of policy-making and implementation can be explained from the aspect of bureaucratic system, energy market running mechanism and others. This paper recommends alterations in the current policy and structure based on these findings.

WRF modeling of PM2.5 remediation by SALSCS and its clean air flow over Beijing terrain

Atmospheric simulations were carried out over the terrain of entire Beijing, China, to investigate the effectiveness of an air-pollution cleaning system named Solar-Assisted Large-Scale Cleaning System (SALSCS) for PM_2.5 mitigation by using the Weather Research and Forecasting (WRF) model. SALSCS was proposed to utilize solar energy to generate airflow therefrom the airborne particulate pollution of atmosphere was separated by filtration elements. Our model used a derived tendency term in the potential temperature equation to simulate the buoyancy effect of SALSCS created with solar radiation on its nearby atmosphere. PM_2.5 pollutant and SALSCS clean air were simulated in the model domain by passive tracer scalars. Simulation conditions with two system flow rates of 2.64 × 10⁵ m³/s and 3.80 × 10⁵ m³/s were tested for seven air pollution episodes of Beijing during the winters of 2015-2017. The numerical results showed that with eight SALSCSs installed along the 6^th Ring Road of the city, 11.2% and 14.6% of PM_2.5 concentrations were reduced under the two flow-rate simulation conditions, respectively.

Direct effect of acid rain on leaf chlorophyll content of terrestrial plants in China

Anthropogenic emissions of acid precursors in China have resulted in widespread acid rain since the 1980s. Although efforts have been made to assess the indirect, soil mediated ecological effects of acid rain, a systematic assessment of the direct foliage injury by acid rain across terrestrial plants is lacking. Leaf chlorophyll content is an important indicator of direct foliage damage and strongly related to plant productivity. We synthesized data from published literature on experiments of simulated acid rain, by directly exposing plants to acid solutions with varying pH levels, to assess the direct effect of acid rain on leaf chlorophyll content across 67 terrestrial plants in China. Our results indicate that acid rain substantially reduces leaf chlorophyll content by 6.71% per pH unit across the recorded plant species. The direct reduction of leaf chlorophyll content due to acid rain exposure showed no significant difference across calcicole, ubiquist or calcifuge species, implying that soil acidity preference does not influence the sensitivity to leaf injury by acid rain. On average, the direct effects of acid rain on leaf chlorophyll on trees, shrubs and herbs were comparable. The effects, however varied across functional groups and economic use types. Specifically, leaf chlorophyll content of deciduous species was more sensitive to acid rain in comparison to evergreen species. Moreover, vegetables and fruit trees were more sensitive to acid rain than other economically used plants. Our findings imply a potential production reduction and economic loss due to the direct foliage damage by acid rain.

Non-linear direct effects of acid rain on leaf photosynthetic rate of terrestrial plants

Anthropogenic emissions of acid precursors have enhanced global occurrence of acid rain, especially in East Asia. Acid rain directly suppresses leaf function by eroding surface waxes and cuticle and leaching base cations from mesophyll cells, while the simultaneous foliar uptake of nitrates in rainwater may directly benefit leaf photosynthesis and plant growth, suggesting a non-linear direct effect of acid rain. By synthesizing data from literature on acid rain exposure experiments, we assessed the direct effects of acid rain on leaf photosynthesis across 49 terrestrial plants in China. Our results show a non-linear direct effect of acid rain on leaf photosynthetic rate, including a neutral to positive effect above pH 5.0 and a negative effect below that pH level. The acid rain sensitivity of leaf photosynthesis showed no significant difference between herbs and woody species below pH 5.0, but the impacts above that pH level were strongly different, resulting in a significant increase in leaf photosynthetic rate of woody species and an insignificant effect on herbs. Our analysis also indicates a positive effect of the molar ratio of nitric versus sulfuric acid in the acid solution on leaf photosynthetic rate. These findings imply that rainwater acidity and the composition of acids both affect the response of leaf photosynthesis and therefore result in a non-linear direct effect.

Air pollution in China: Status and spatiotemporal variations

In recent years, China has experienced severe and persistent air pollution associated with rapid urbanization and climate change. Three years' time series (January 2014 to December 2016) concentrations data of air pollutants including particulate matter (PM_2.5 and PM₁₀) and gaseous pollutants (SO₂, NO₂, CO, and O₃) from over 1300 national air quality monitoring sites were studied to understand the severity of China's air pollution. In 2014 (2015, 2016), annual population-weighted-average (PWA) values in China were 65.8 (55.0, 50.7) μg m^-3 for PM_2.5, 107.8 (91.1, 85.7) μg m^-3 for PM₁₀, 54.8 (56.2, 57.2) μg m^-3 for O₃_8 h, 39.6 (33.3, 33.4) μg m^-3 for NO₂, 34.1 (26, 21.9) μg m^-3 for SO₂, 1.2 (1.1, 1.1) mg m^-3 for CO, and 0.60 (0.59, 0.58) for PM_2.5/PM₁₀, respectively. In 2014 (2015, 2016), 7% (14%, 19%), 17% (27%, 34%), 51% (67%, 70%) and 88% (97%, 98%) of the population in China lived in areas that meet the level of annual PM_2.5, PM₁₀, NO₂, and SO₂ standard metrics from Chinese Ambient Air Quality Standards-Grade II. The annual PWA concentrations of PM_2.5, PM₁₀, O₃_8 h, NO₂, SO₂, CO in the Northern China are about 40.4%, 58.9%, 5.9%, 24.6%, 96.7%, and 38.1% higher than those in Southern China, respectively. Though the air quality has been improving recent years, PM_2.5 pollution in wintertime is worsening, especially in the Northern China. The complex air pollution caused by PM and O₃ (the third frequent major pollutant) is an emerging problem that threatens the public health, especially in Chinese mega-city clusters. NOx controls were more beneficial than SO₂ controls for improvement of annual PM air quality in the northern China, central, and southwest regions. Future epidemiologic studies are urgently required to estimate the health impacts associated with multi-pollutants exposure, and revise more scientific air quality index standards.

GHGs and air pollutants embodied in China's international trade: Temporal and spatial index decomposition analysis

Temporal index decomposition analysis and spatial index decomposition analysis were applied to understand the driving forces of the emissions embodied in China's exports and net exports during 2002-2011, respectively. The accumulated emissions embodied in exports accounted for approximately 30% of the total emissions in China; although the contribution of the sectoral total emissions intensity (technique effect) declined, the scale effect was largely responsible for the mounting emissions associated with export, and the composition effect played a largely insignificant role. Calculations of the emissions embodied in net exports suggest that China is generally in an environmentally inferior position compared with its major trade partners. The differences in the economy-wide emission intensities between China and its major trade partners were the biggest contribution to this reality, and the trade balance effect played a less important role. However, a lower degree of specialization in pollution intensive products in exports than in imports helped to reduce slightly the emissions embodied in net exports. The temporal index decomposition analysis results suggest that China should take effective measures to optimize export and supply-side structure and reduce the total emissions intensity. According to spatial index decomposition analysis, it is suggested that a more aggressive import policy was useful for curbing domestic and global emissions, and the transfer of advanced production technologies and emission control technologies from developed to developing countries should be a compulsory global environmental policy option to mitigate the possible leakage of pollution emissions caused by international trade.

Air Pollution Control Policies in China: A Retrospective and Prospects

With China’s significant role on pollution emissions and related health damage, deep and up-to-date understanding of China’s air pollution policies is of worldwide relevance. Based on scientific evidence for the evolution of air pollution and the institutional background of environmental governance in China, we examine the development of air pollution control policies from the 1980s and onwards. We show that: (1) The early policies, until 2005, were ineffective at reducing emissions; (2) During 2006–2012, new instruments which interact with political incentives were introduced in the 11th Five-Year Plan, and the national goal of reducing total sulfur dioxide (SO₂) emissions by 10% was achieved. However, regional compound air pollution problems dominated by fine particulate matter (PM_2.5) and ground level ozone (O₃) emerged and worsened; (3) After the winter-long PM_2.5 episode in eastern China in 2013, air pollution control policies have been experiencing significant changes on multiple fronts. In this work we analyze the different policy changes, the drivers of changes and key factors influencing the effectiveness of policies in these three stages. Lessons derived from the policy evolution have implications for future studies, as well as further reforming the management scheme towards air quality and health risk oriented directions.

Health benefits from improved outdoor air quality and intervention in China

China is at its most critical stage of outdoor air quality management. In order to prevent further deterioration of air quality and to protect human health, the Chinese government has made a series of attempts to reduce ambient air pollution. Unlike previous literature reviews on the widespread hazards of air pollution on health, this review article firstly summarized the existing evidence of human health benefits from intermittently improved outdoor air quality and intervention in China. Contents of this paper provide concrete and direct clue that improvement in outdoor air quality generates various health benefits in China, and confirm from a new perspective that it is worthwhile for China to shift its development strategy from economic growth to environmental economic sustainability. Greater emphasis on sustainable environment design, consistently strict regulatory enforcement, and specific monitoring actions should be regarded in China to decrease the health risks and to avoid long-term environmental threats.

Enhanced air pollution via aerosol-boundary layer feedback in China

Severe air pollution episodes have been frequent in China during the recent years. While high emissions are the primary reason for increasing pollutant concentrations, the ultimate cause for the most severe pollution episodes has remained unclear. Here we show that a high concentration of particulate matter (PM) will enhance the stability of an urban boundary layer, which in turn decreases the boundary layer height and consequently cause further increases in PM concentrations. We estimate the strength of this positive feedback mechanism by combining a new theoretical framework with ambient observations. We show that the feedback remains moderate at fine PM concentrations lower than about 200 μg m⁻³, but that it becomes increasingly effective at higher PM loadings resulting from the combined effect of high surface PM emissions and massive secondary PM production within the boundary layer. Our analysis explains why air pollution episodes are particularly serious and severe in megacities and during the days when synoptic weather conditions stay constant.

Study of Reciprocal Effects between Mandatory Pollutant Emissions Reduction Policy and Structural Change within the Manufacturing Sector in a Chinese Coastal Area

We develop a multicriteria decision-making model coupled with scenario analysis to quantitatively elucidate the reciprocal effect between a mandatory pollutant emissions reduction policy and industrial structure change within the manufacturing sector on the basis of an in-depth study of a well-developed coastal area in East China, Ningbo City, toward 2020. First, 18 two-digit level industries (TDLIs) in the manufacturing sector are screened out due to intensive emissions of the four pollutants (COD, NH3-N, SO2, and NOx). Second, a model is established to identify the optimal solution for the industrial structure adjustment of the 18 TDLIs under two scenarios, the "business-as-usual" scenario and the "industrial structure adjustment" scenario. Both scenarios are expanded into three subscenarios. Quantitative constraint conditions and two criteria are formulated to screen out the optimal solutions. We propose a coefficient of industrial structure adjustment, Ki, which could clearly reflect the policy preference in terms of industrial development and reallocate the quota of the four-pollutant emission among the 18 TDLIs with regards to the different expectations of economy development in 2020. The model will help local authorities make tailored policies to reduce pollution emissions effectively through industrial structure change by delicately allocating the pollutant emission quota and setting reasonable targets of emission intensity reduction among TDLIs.

Spatial boundary of urban 'acid islands' in southern China

Elevated emissions of sulfur dioxide, nitrogen oxides and ammonia in China have resulted in high levels of sulfur and nitrogen deposition, being contributors to soil acidification, especially in and near large cities. However, knowledge gaps still exist in the way that large cities shape spatial patterns of acid deposition. Here, we assessed the patterns of pH, sulfate, nitrate and ammonium in bulk precipitation and throughfall in southern China's forests by synthesizing data from published literature. Concentrations and fluxes of sulfate, nitrate and ammonium in bulk precipitation and throughfall exhibited a power-law increase with a closer distance to the nearest large cities, and accordingly pH showed a logarithmic decline. Our findings indicate the occurrence of urban 'acid islands' with a critical radius of approximately 70 km in southern China, receiving potential acid loads of more than 2 keq ha(-1) yr(-1). These urban acid islands covered an area of 0.70 million km(2), accounting for nearly 30% of the land area in southern China. Despite a significant capacity to neutralize acids in precipitation, our analysis highlights a substantial contribution of ammonium to potential acid load. Our results suggest a joint control on emissions of multiple acid precursors from urban areas in southern China.

Can China comply with its 12th five-year plan on industrial emissions control: a structural decomposition analysis

China's rapid economic growth has caused serious environmental problems, resulting in the implementation of two major measures-end-of-pipe facilities and the phasing out of backward capacity-to reduce China's industrial emissions as part of its 11th Five-Year Plan (FYP, 2006-2010). It is important to determine whether China can meet the targets set forth in its 12th FYP (2011-2015) for industrial pollution reduction using these same solutions. In this paper, structural decomposition analysis (SDA) was used to identify the contributions of the adopted measures-as well as other underlying factors-and to evaluate the feasibility of the reduction target in China's 12th FYP. Results show that the decrease in major industrial pollutant emissions achieved during the 11th FYP resulted from improved technological efficiency, including end-of-pipe abatement efficiency and pollutant generation intensity. The same measures adopted during China's 12th FYP can address the problem of industrial wastewater emissions resulting from economic growth when the economic structure is kept constant. But it may not fulfill its commitment of reducing industrial atmospheric pollutants emissions unless the economic structure and growth patterns are drastically reformed.