Emission Control Measures Research Articles

Variation of platinum group elements (PGE) in airborne particulate matter (PM2.5) in the Beijing urban area, China: A case study of the 2014 APEC summit

Platinum (Pt), palladium (Pd) and rhodium (Rh) are accumulating globally in the environment due to their use as catalysts to control automotive exhaust emissions. The aim of this study was to evaluate the effect of emission control measures on the changes in platinum group elements (PGE) concentrations in airborne particulate matter (atmospheric particulate mat-ter of aerodynamic diameter ≤2.5 μm, PM2.5) during the 2014 Asia-Pacific Economic Cooperation (APEC) Summit held in Beijing. Airborne samples were collected from Beijing urban areas with high volumes of traffic. Samples were treated using microwave-assisted digestion procedures, and the concentrations of PGE were determined by inductively coupled plasma mass spectrometry (ICP-MS).The PGE concentration during the APEC summit decreased by 35.13% and 35.21%, compared with before and after the summit, respectively, which were smaller than the corresponding decreases in the PM2.5 concentrations (∼53.9% and 50.5%, respectively). The results provide data regarding PGE accumulation trends in the urban atmospheric environments, which is ascribed to their use as catalysts in automotive catalytic converters. The results highlight the need to continue monitoring the accumulation of PGE, most notably Pd, in the urban atmospheric environment.

Unintended Effects of Residential Energy Storage on Emissions from the Electric Power System.

In many jurisdictions, policy-makers are seeking to decentralize the electric power system while also promoting deep reductions in the emission of greenhouse gases (GHG). We examine the potential roles for residential energy storage (RES), a technology thought to be at the epicenter of these twin revolutions. We model the impact of grid-connected RES operation on electricity costs and GHG emissions for households in 16 of the largest U.S. utility service territories under 3 plausible operational modes. Regardless of operation mode, RES mostly increases emissions when users seek to minimize their electricity cost. When operated with the goal of minimizing emissions, RES can reduce average household emissions by 2.2-6.4%, implying a cost equivalent of $180 to $5160 per metric ton of carbon dioxide avoided. While RES is costly compared with many other emission-control measures, tariffs that internalize the social cost of carbon would reduce emissions by 0.1-5.9% relative to cost-minimizing operation. Policy-makers should be careful about assuming that decentralization will clean the electric power system, especially if it proceeds without carbon-mindful tariff reforms.

A new panel for analyzing the impact factors on carbon emission: A regional perspective in China

As the largest carbon emitter in the world, China is under pressure in addressing carbon emission reduction. It is important for the country to understand the impact factors on emission so that proper mitigation measures can be taken. Previous studies have analyzed emission factors through classifying regions mainly by a single economic index or carbon index, whereas this study introduces a two-dimensional panel framework to classify regions. These two dimensions are per capita GDP and carbon intensity. Based on this panel framework, the 30 provinces in China are classified into four regions, namely, high economy and high carbon intensity (Region I), high economy and low carbon intensity (Region II), low economy and low carbon intensity (Region III), and low economy and high carbon intensity (Region IV). The STIRPAT (stochastic impacts by regression on population, affluence, and technology) model and the panel cointegration approach are employed to analyze the impacts of various carbon emission factors in the four classified regions. The results show that the most significant factor for Region I is industrial structure, and that for Regions II, III and IV is energy intensity, population size and per capita GDP respectively. The research results can help decision makers adopt effective emission control measures. The two-dimensional panel framework introduced can be extended for application to examine the emission impact factors at regional or national levels in other countries.

Characterization and Risk Assessment of Atmospheric PM2.5 and PM10 Particulate-Bound PAHs and NPAHs in Rwanda, Central-East Africa.

Exposure to airborne particulates is estimated as the largest cause of premature human mortality worldwide and is of particular concern in sub-Saharan Africa where emissions are high and data are lacking. Particulate matter (PM) contains several toxic organic species including polycyclic aromatic hydrocarbons (PAHs) and nitrated PAHs (NPAHs). This study provides the first characterization and source identification for PM10- and PM2.5-bound PAHs and NPAHs in sub-Saharan Africa during a three-month period that spanned dry and wet seasons at three locations in Rwanda. The 24-h mean PM2.5 and PM10 concentrations were significantly higher in the dry than the wet season. PAH and NPAH concentrations at the urban roadside site were significantly higher than the urban background and rural site. Source identification using diagnostic ratio analysis and principal component analysis (PCA) revealed diesel and gasoline-powered vehicles at the urban location and wood burning at the rural location as the major sources of PAHs and NPAHs. Our analysis demonstrates that PM concentrations and lifetime cancer risks resulting from inhalation exposure to PM-bound PAHs and NPAHs exceed World Health Organization safe limits. This study provides clear evidence that an immediate development of emission control measures is required.

Quantitative Analysis of Health Risk Perception, Exposure Levels, and Willingness to Pay/Accept of PM2.5 during the 2014 Nanjing Youth Olympic Games.

Local governments in China regularly implement short-term emission control measures to improve air quality during important sporting events. As a condition for hosting the 2014 Youth Olympic Games (YOG), the Nanjing government agreed to temporarily and substantially improve air quality. Regression analysis, Spearman correlation analysis, χ2 test, and the contingent valuation method were used to explore the effects of robust, short-term air pollution control measures on risk perception, daily exposure to PM2.5, risk acceptance levels, and willingness to pay/accept (WTP/WTA) for reductions in air pollution for the benefit of reducing health risks. Postimplementation, the respondents' risk perception levels presented the following changes: during the YOG, the respondents perceived the lowest effects of haze pollution while after the YOG, they perceived the highest effects. The changes in risk acceptance levels showed the same tendency. Furthermore, after the YOG, the respondents asked for the most economic compensation, and their willingness to pay for risk reduction also reached the highest level. This study reveals the need to increase the public's understanding of the health risks of air pollution, protect those populations most exposed to high levels of PM2.5, and take more effective long-term measures to meet local residents' demands for improved air quality.

PM2.5 concentration and composition in the urban air of Nanjing, China: Effects of emission control measures applied during the 2014 Youth Olympic Games

Industrial processes, coal combustion, biomass burning (BB), and vehicular transport are important sources of atmospheric fine particles (PM2.5) and contribute to ambient air concentrations of health-hazardous species, such as heavy metals, polycyclic aromatic hydrocarbons (PAH), and oxygenated-PAHs (OPAH). In China, emission controls have been implemented to improve air quality during large events, like the Youth Olympic Games (YOG) in August 2014 in Nanjing. In this work, six measurement campaigns between January 2014 and August 2015 were undertaken in Nanjing to determine the effects of emission controls and meteorological factors on PM2.5 concentration and composition. PAHs, OPAHs, hopanes, n‑alkanes, heavy metals, and several other inorganic elements were measured. PM2.5 and potassium concentrations were the highest in May–June 2014 indicating the prevalence of BB plumes in Nanjing. Emission controls substantially reduced concentrations of PM2.5 (31%), total PAHs (59%), OPAHs (37%), and most heavy metals (44–89%) during the YOG compared to August 2015. In addition, regional atmospheric transport and meteorological parameters partly explained the observed differences between the campaigns. The most abundant PAHs and OPAHs were benzo[b,k]fluoranthenes, fluoranthene, pyrene, chrysene, 1,8‑naphthalic anhydride, and 9,10‑anthracenedione in all campaigns. Carbon preference index and the contribution of wax n‑alkanes indicated mainly biogenic sources of n‑alkanes in May–June 2014 and anthropogenic sources in the other campaigns. Hopane indexes pointed to vehicular transport as the major source of hopanes, but contribution of coal combustion was detected in winter 2015. The results provide evidence to the local government of the impacts of the air protection regulations. However, differences between individual components were observed, e.g., concentrations of potentially more harmful OPAHs decreased less than concentrations of PAHs. The results suggest that the proportions of hazardous components in the PM2.5 may also change considerably due to emission control measures.

Reduction measures for air pollutants and greenhouse gas in the transportation sector: A cost-benefit analysis

Cost-benefit analysis of emission control measures is an important part of the development and refinement of policies in the transportation sector, especially in China. In this paper, a cost-benefit analysis of the measures in place to reduce air pollutants [carbon monoxide (CO), volatile organic compounds (VOCs), nitrogen oxides (NOX), fine particulate matter (PM2.5)] and greenhouse gases (GHGs) [carbon dioxide (CO2)] in the Pearl River Delta (PRD) region by 2020 is conducted. Based on the design of five types of emission reduction scenarios and normalization of the emission reduction effect, the total costs and the cost-benefit of these reduction scenarios in the PRD region by 2020 are evaluated. Results show the scenario, which new cars bought after 2014 are all upgraded from China V emission standard to China VI emission standard and motorcycles are still China III emission standard (UES), has a significant effect with 717,690 tons of the air pollutants equivalent and 38,960 tons of the GHGs equivalent reduction, while the Eliminate Motorcycles (EM) scenario produces the worst emissions reduction result. Therefore the cost-benefit of the UES scenario is extremely high, and the unit cost of air pollutants and GHGs reductions is only 0.003 Renminbi/g (RMB/g), showing a win-win situation of emission reduction and cost savings. Although the total cost of the BPSevere scenario, giving priority to public transportation development to reduce the mobility for private cars and motorcycles, is the highest (197.47 billion RMB), it can effectively reduce 9925 tons of GHGs equivalent and bring significant climate benefits. Moreover, for any reduction scenarios, the cost-benefit cannot be improved by strengthening the control level. And the comparison of the unit reduction costs among four different sectors shows that the cost-benefits of reduction scenarios in the transportation sector are worse and more variable.

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.

Estimation of Vessel Emissions Inventory in Qingdao Port Based on Big data Analysis

Exhaust emissions from vessels have increasingly attracted attention in the continuously growing marine transport world trade market. The International Maritime Organization (IMO) has introduced a number of measures designed to reduce exhaust emissions from global shipping. As one of the busiest ports in the world, Qingdao port has been studied to propose possible support to the development of efficient emission reduction. In this study, a large amount data of emissions inventory in Qingdao port was used to predict its annual exhaust emissions, and hence, to help understand maritime pollution in Qingdao port. Bigdata analysis methodology was employed to perform accurate predictions on vessel emissions. The analysis results show that the emissions were dominated by container ships, oil tankers, and bulk cargo ships. The comparison between Qingdao port and other ports in emission control areas demonstrates the necessity of control measures for exhaust emissions. The adoption of shore power and efficient cargo handling seems to be a potential solution to reduce exhaust emissions. The findings of this study are meaningful for maritime safety administration to understand the current emission situation in Qingdao port, propose corresponding control measures, and perform pollution prevention.

Impact of biomass burning and its control on particulate matter over a city in mainland Southeast Asia during a smog episode

Cities in mainland Southeast Asia have long faced smog problems. Developing effective control strategies for smog reduction has been a challenge for academics and policy makers. In this study, emission control measures were assessed using both the Weather Research and Forecasting (WRF) and Community Multi-scale Air Quality (CMAQ) modeling systems during a smog episode between 1st and 31st of March 2012. The study found that there was a strong impact from biomass burning outside of the city on PM concentrations within the city, with contributions of approximately 85% and 89% for PM10 and PM2.5 respectively. Control of biomass burning in the city significantly affects local PM concentrations. This study investigated the success of biomass burning control inside the city when no biomass is burned outside of the city. The control scenarios focused on specific reduction levels in biomass burning emissions, which included 0%, 20%, 40%, 60%, 80% and 100%. The results yielded the following rates: the mean PM2.5 concentrations decreased by 0.70% per %decrease of biomass burning emission; the maximum daily average PM2.5 concentrations decreased by 0.84% per %decrease of biomass burning emission; and the average percentage of PM2.5 concentrations that exceeded the NAAQS decreased by 1.05% per %decrease of biomass burning emission. This information provide good guidelines for successful decision-making at each control level to solve the problems related to of smog in cities. However, smog problems cannot only be solved by emission control measures in the city; biomass burning must also be reduced on a regional scale.

Counteractive effects of regional transport and emission control on the formation of fine particles: a case study during the Hangzhou G20 summit

Abstract. To evaluate the effect of temporary emission control measures on air quality during the 2016 G20 summit held in Hangzhou, China, an intensive field campaign was conducted with a focus on aerosol chemistry and gaseous precursors from 15 August to 12 September 2016. The concentrations of fine particles were reduced during the intense emission control stages, with the reduction of carbonaceous matter being mostly responsible for this observed decrease. This, in turn, was mainly ascribed to the decrease of secondary organic aerosols via the suppression of daytime peak secondary organic carbon (SOC)formation. Although the regional joint control was enacted extending to the Yangtze River Delta region, the effect of long-range transport on the air quality of Hangzhou was ubiquitous. Unexpectedly high NOx concentrations were observed during the control stage, when the strictest restriction on vehicles was implemented, owing to contributions from upstream populous regions such as Jiangsu and Shandong provinces. In addition, the continental outflow traveling over the ocean triggered a short pollution episode on the first day of the G20 summit, resulting in a significant enhancement of the nitrogen/sulfur oxidation rates. In the wake of the summit, all air pollutants evidently rebounded after the various control measures were lifted. Overall, the fraction of secondary inorganic aerosols (SIA; in this case sulfate, nitrate, and ammonium aerosols – SNA) in PM2.5 increased as relative humidity increased; however, the overall concentration of PM2.5 did not increase. Aerosol components that had distinctly different sources and formation mechanisms, e.g., sulfate/nitrate and elemental carbon, exclusively showed strong correlations during the regional/long-range transport episodes. The sulfate, nitrate, and ammonium to elemental carbon (SNA∕EC) ratio, which was used as a proxy for assessing the extent of secondary inorganic aerosol formation, was found to be significantly enhanced under transport conditions from northern China. This study highlighted that emission control strategies were beneficial for curbing particulate pollution, in addition to the fact that regional/long-range transport may offset local emission control effects to some extent.

A Quantitative Analysis of Health Risk Perception, Exposure Levels, and WTP/WTA of PM2.5 during the 2014 Nanjing Youth Olympic Games

Local governments in China regularly implement authoritative short-term emission control measures to improve air quality during important sporting events. As a condition for hosting the 2014 Youth ...

Source Apportionment and Secondary Transformation of Atmospheric Nonmethane Hydrocarbons in Chengdu, Southwest China

AbstractNonmethane hydrocarbons (NMHCs) have an important influence on the formation of photochemical smog and secondary organic aerosols in the atmosphere. We investigated 55 NMHCs in Chengdu from 27 October 2016 to 30 September 2017 to identify their sources, pollution levels, and secondary transformation potential. The average concentration of NMHCs in Chengdu was 41.8 ± 20.8 ppbv. Meteorological conditions play a vital role in the formation and dispersion of NMHCs, PM2.5, and O3. The photochemical conversion of NMHCs was inhibited by lower solar radiation, leading to low O3 concentrations and high NMHC concentrations. Aromatics and alkenes played a leading role in the secondary transformation, accounting for 60 ± 16% and 29 ± 11% of the total secondary formation potential, respectively. The southwest air mass trajectory was the most significant transportation path affecting the NMHC concentration in Chengdu. The results of the positive matrix factorization model indicated that there were seasonal differences in the sources of NMHCs in Chengdu. Four major emission sources were identified, namely, vehicle exhaust, industrial, paint solvents, and biogenic sources. Vehicle exhaust emissions were the greatest contributor to NMHCs in Chengdu, accounting for approximately 45% of the NMHCs. Overall, toluene, m/p‐xylene and ethylbenzene constitute a large fraction of the calculated ozone and secondary aerosol formation potential. Future studies should consider targeting these compounds when evaluating ozone and aerosol reduction strategies. However, in terms of total control of NMHC pollution, Chengdu should focus on effective control measures for traffic emissions.

Impact of air pollution control policies on future PM2.5 concentrations and their source contributions in China

To investigate the impact of air pollutant control policies on future PM2.5 concentrations and their source contributions in China, we developed four future scenarios for 2030 based on a 2013 emission inventory, and conducted air quality simulations for each scenario using the chemical transport model GEOS-Chem (version 9.1.3). Two energy scenarios i.e., current legislation (CLE) and with additional measures (WAM), were developed to project future energy consumption, reflecting, respectively, existing legislation and implementation status as of the end of 2012, and new energy-saving policies that would be released and enforced more stringently. Two end-of-pipe control strategies, i.e., current control technologies (until 2017) and more stringent control technologies (until 2030), were also developed. The combinations of energy scenarios and end-of-pipe control strategies constitute four emission scenarios (2017-CLE, 2030-CLE, 2017-WAM, and 2030-WAM) evaluated in simulations. PM2.5 concentrations at national level were estimated to be 57 μg/m3 in the base year 2013, and 58 μg/m3, 42 μg/m3, 42 μg/m3, and 30 μg/m3 under the 2017-CLE, 2030-CLE, 2017-WAM, and 2030-WAM scenarios in 2030, respectively. Large PM2.5 reductions between 2013 and 2030 were estimated for heavily polluted regions (Sichuan Basin, Middle Yangtze River, North China). The energy-saving policies show similar effects to the end-of-pipe emission control measures, but the relative importance of these two groups of policies varies in different regions. Absolute contributions to PM2.5 concentrations from most major sources declined from 2017-CLE to 2030-WAM. With respect to fractional contributions, most coal-burning sectors (including power plant, industrial and residential coal burning) increased from 2017-CLE to 2030-WAM, due to larger reductions from non-coal sources, including transportation and biomass open burning. Residential combustion and open burning had much lower fractional contribution to ambient PM2.5 concentrations in the 2017-WAM/2030-WAM compared to the 2017-CLE/2030-CLE scenarios. Fractional contributions from transportation were reduced dramatically in 2030-CLE and 2030-WAM compared to 2017-CLE/2017-WAM, due to the enforcement of stringent end-of-pipe emission controls. Across all scenarios, coal combustion remained the single largest contributor to PM2.5 concentrations in 2030. Reducing PM2.5 emissions from coal combustion remains a strategic priority for air quality management in China.

Projections for temperature-related years of life lost from cardiovascular diseases in the elderly in a Chinese city with typical subtropical climate

ObjectiveExtreme temperature is an important risk factor for cardiovascular diseases, and the elderly are particularly vulnerable to temperature variation. Global warming and the increasingly aging population are two major global challenges for human health; thus, an urgent need exists to project the temperature-related cardiovascular disease burden regarding both of the aforementioned factors. We aimed to the project temperature-related burden of cardiovascular diseases using years of life lost (YLL) in the elderly in a Chinese city with typical subtropical climate. MethodsA retrospective time-series study was first conducted to estimate cardiovascular disease burden associated with temperature in the elderly from 2008 to 2015 in Ningbo, China. Then, future projections considering demographic change and adaptation under 19 global-scale climate models (GCMs) and 3 different Representative Concentration Pathways (RCPs) scenarios for the 2050s and 2070s were estimated. ResultsThe exposure-response curve for temperature on YLL from cardiovascular diseases was U-shaped, with increased YLL for both higher- and lower- than optimal temperature. The projected annual increase in heat-related YLL was outweighed by the decrease in cold-related YLL. However, monthly analysis demonstrated that temperature-related YLL will increase significantly in August. Additionally, heat-related YLL is projected to increase 3.1–11.5 times for the 2050s and 2070s relative to baseline, when considering demographic changes, even with 30% adaptation taken into consideration. ConclusionsAlthough annual YLL from cardiovascular diseases in the elderly associated with temperature will decrease in the future, heat-related YLL will increase tremendously, which indicates that more adaptation strategies and greenhouse emission control measures should be undertaken to reduce the future heat-related burden of cardiovascular diseases in the elderly.

A real option application for emission control measures

Real Option analyses are broadly discussed in economics and finance and different analytic and numeric calculation methods for option values have been presented and successfully implemented in theoretical case studies and practical applications. However, real option analysis has not yet been applied for mandatory investments without monetary revenues, e.g. investments in pollution reduction and emission control installations in large industrial plants enforced by political regulation. The assessment of the timing of the investment, i.e. whether to invest immediately or to delay the investment in the future, is the main scope of this work. A difficulty of the underlying type of investments with regard to option valuation is that not to invest is not an option. Therefore, the frequently applied optimal stopping approaches based on investment thresholds are not applicable to this work. In the first part of the paper, specific features and characteristics of the regarded investments are analyzed and translated into financial terms of option valuation, accompanied by an overview of several relevant option valuation methods. The most appropriate methodology for the application, the Monte-Carlo-Analysis, will be assessed in more detail. Based on a two perspectives approach that analyzes possible savings and losses of a delayed investment, a case study displays the calculations and results of the developed methodology in several scenarios. The case study reveals possible influences of policy schemes and the impact of the degree of uncertainty on mandatory investments. The work has a strong methodological focus and the calculation methodology provided can be of use for investors and policy-makers, particularly with regard to investment decision-making in the real options framework and the design of political instruments such as funding schemes.

Environmental Challenges and Current Practices in China—A Thorough Analysis

This study presents a critical analysis of the environmental challenges regarding global environmental policies and current practices in China. The study provides imperative evidence about the current emission control strategies, environmental planning, legislation, policy instruments, and measures to provide a sustainable environment for the present and future generations. The study followed a well-defined analytical methodology to analyse the measures adopted to control emissions as a trade-balancing tool for the environment. The findings indicated that domestic as well as the international collaborations were effective in controlling the present problem of environmental pollution, and suggested a need for collaborative agreements to amend the Environmental Protection Law (EPL). The analytical findings determined that the proposed EPL considered SO2 or NO2 emissions while neglecting an important source of environmental pollution, i.e., CO2 emissions. The research findings also suggested a need for to accelerate efforts in a more professional, practical, and result-oriented manner to analyse the diverse nature of environmental issues. The research highlighted some of the obstacles to the successful implementation of EPL for current and future environmental challenges.

Attribution of aerosol direct radiative forcing in China and India to emitting sectors

Strict emission control measures are being implemented in China and India to improve air quality and protect human health, yet current air quality driven and sector based measures without consideration of climate effects would likely taccelerate warming. In this study, we attribute aerosol direct radiative forcing in China and India to emitting sectors using a fully online coupled meteorology-chemistry model (WRF-Chem, Weather Research and Forecasting Model coupled with Chemistry) for the entire year of 2013. Our simulations show that the observed spatial and temporal variations of aerosol concentrations and optical properties are generally reproduced by the model, although sulfate is biased low in winter due to missing aqueous/heterogeneous pathways in the model. Aerosols from all sectors result in negative direct forcing at the top of the atmosphere (TOA) in both China (−2.21 W/m2) and India (−3.18 W/m2), which are largely contributed by the power sector. The residential sector in both China and India largely heats the atmosphere because of its dominant contribution to black carbon emissions. In both China and India, the longwave radiative forcing (0.86 and 1.21 W/m2 for China and India) is tiny compared to the shortwave radiative forcing (−3.07 and −4.39 W/m2 for China and India). The seasonality of sectoral radiative forcing in China is different from that in India. These results suggest that residential sector should be targeted to achieve both air quality and climate change goals, yet the control of emissions from the power sector is very likely to accelerate warming.

Decomposing Air Pollutant Emissions in Asia: Determinants and Projections

High levels of air pollution pose an urgent social and public health challenge in many Asian regions. This study evaluates the role of key factors that determined the changes in emission levels in China, India and Japan over the past 25 years. While emissions of air pollutants have been declining in Japan since the 1990s, China and India have experienced a rapid growth in pollution levels in recent years. Around 2005, control measures for sulfur emissions started to deliver expected reductions in China, followed by cuts in nitrogen oxides ten years later. Despite recent policy interventions, growing emission trends in India persist. A decomposition analysis of emission-driving factors indicates that emission levels would have been at least two-times higher without the improvements in energy intensity and efficiency, combined with end-of-pipe measures. Due to the continuous reliance on fossil fuels, the abatement effect of a cleaner fuel mix was in most cases significantly smaller than other factors. A reassessment of emission projections developed in the past suggests a decisive impact of energy and environmental policies. It is expected that targeted legislative instruments will play a dominant role in achieving future air-quality goals in Asia.

Source apportionment of fine particulate matter organic carbon in Shenzhen, China by chemical mass balance and radiocarbon methods

Chemical mass balance (CMB) modeling and radiocarbon measurements were combined to evaluate the sources of carbonaceous fine particulate matter (PM2.5) in Shenzhen, China during and after the 2011 summer Universiade games when air pollution control measurements were implemented to achieve air quality targets. Ambient PM2.5 filter samples were collected daily at two sampling sites (Peking University Shenzhen campus and Longgang) over 24 consecutive days, covering the controlled and uncontrolled periods. During the controlled period, the average PM2.5 concentration was less than half of what it was after the controls were lifted. Organic carbon (OC), organic molecular markers (e.g., levoglucosan, hopanes, polycyclic aromatic hydrocarbons), and secondary organic carbon (SOC) tracers were all significantly lower during the controlled period. After pollution controls ended, at Peking University, OC source contributions included gasoline and diesel engines (24%), coal combustion (6%), biomass burning (12.2%), vegetative detritus (2%), biogenic SOC (from isoprene, α-pinene, and β-caryophyllene; 7.1%), aromatic SOC (23%), and other sources not included in the model (25%). At Longgang after the controls ended, similar source contributions were observed: gasoline and diesel engines (23%), coal combustion (7%), biomass burning (17.7%), vegetative detritus (1%), biogenic SOC (from isoprene, α-pinene, and β-caryophyllene; 5.3%), aromatic SOC (13%), and other sources (33%). The contributions of the following sources were smaller during the pollution controls: biogenic SOC (by a factor of 10–16), aromatic SOC (4–12), coal combustion (1.5–6.8), and biomass burning (2.3–4.9). CMB model results and radiocarbon measurements both indicated that fossil carbon dominated over modern carbon, regardless of pollution controls. However, the CMB model needs further improvement to apportion contemporary carbon (i.e. biomass burning, biogenic SOC) in this region. This work defines the major contributors to carbonaceous PM2.5 in Shenzhen and demonstrates that control measures for primary emissions could significantly reduce secondary organic aerosol (SOA) formation.