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Black carbon mitigation has received increasing attention for its potential contribution to both climate change mitigation and air pollution control. Although different bottom-up models concerned with unit mitigation costs of various technologies allow the assessment of alternative policies for optimized cost-effectiveness, the lack of adequate data often forced many reluctant explicit and implicit assumptions that deviate away from actual situations of rural residential energy consumption in developing countries, where most black carbon emissions occur. To gauge the theory-practice gap in black carbon mitigation – the unit cost differences that lie between what is estimated in the theory and what is practically achieved on the ground – this study conducted an extensive field survey and analysis of nine mitigation technologies in rural China, covering both northern and southern regions with different residential energy consumption patterns. With a special focus on two temporal characteristics of those technologies – lifetimes and annual utilization rates, this study quantitatively measured the unit cost gaps and explain the technical as well as sociopolitical mechanisms behind. Structural and behavioral barriers, which have affected the technologies’ performance, are discussed together with policy implications to narrow those gaps. [ABSTRACT FROM AUTHOR]

A systematic dataset of an observation network on a national scale has been organized to investigate the spatial distribution of bulk sulfur (S) deposition (S dep ) throughout China during 2000–2013, representing by far the most detailed data set to track the bulk sulfur deposition throughout China since 2000. Such a dataset is needed for ecosystem studies and for developing emission control policies. Bulk S dep values showed great variations, ranging from 2.17 to 70.55 kg ha −1 y −1 , with an average of 22.99 kg ha −1 y −1 . The average rate of bulk S dep located in East Coastal region (35.97 kg ha −1 y −1 ), Middle Yangtze region (57.90 kg ha −1 y −1 ), Middle Yellow River region (23.42 kg ha −1 y −1 ), North Coastal region (42.19 kg ha −1 y −1 ), Northeast region (34.28 kg ha −1 y −1 ), South Coastal region (36.97 kg S ha −1 y −1 ), Southwest region (33.85 kg ha −1 y −1 ) was 4.50, 7.24, 2.93, 5.28, 4.29, 4.63 and 4.24 times than that in Northwest region (7.99 kg ha −1 y −1 ). Bulk S dep over China was mainly from fossil fuel combustion (76.96%), biomass burning (7.64%), crust (6.22%), aged sea salt (5.48%) and agriculture (3.68%). A systematic observation network on a national scale should be established to conduct a long-term monitoring atmospheric S dep (including wet and dry deposition), based on exiting ecological stations administrated by different departments in China. [ABSTRACT FROM AUTHOR]

An extremely severe and persistent haze event occurred over the middle and eastern China in January 2013, with the record-breaking high concentrations of fine particulate matter (PM 2.5 ). In this study, an online-coupled meteorology-air quality model, the Weather Research and Forecasting Model with Chemistry (WRF/Chem), is applied to simulate this pollution episode over East Asia and northern China at 36- and 12-km grid resolutions. A number of simulations are conducted to examine the sensitivities of the model predictions to various physical schemes. The results show that all simulations give similar predictions for temperature, wind speed, wind direction, and humidity, but large variations exist in the prediction for precipitation. The concentrations of PM 2.5 , particulate matter with aerodynamic diameter of 10 μm or less (PM 10 ), sulfur dioxide (SO 2 ), and nitrogen dioxide (NO 2 ) are overpredicted partially due to the lack of wet scavenging by the chemistry-aerosol option with the 1999 version of the Statewide Air Pollution Research Center (SAPRC-99) mechanism with the Model for Simulating Aerosol Interactions and Chemistry (MOSAIC) and the Volatility Basis Set (VBS) for secondary organic aerosol formation. The optimal set of configurations with the best performance is the simulation with the Gorddard shortwave and RRTM longwave radiation schemes, the Purdue Lin microphysics scheme, the Kain-Fritsch cumulus scheme, and a nudging coefficient of 1 × 10 −5 for water vapor mixing ratio. The emission sensitivity simulations show that the PM 2.5 concentrations are most sensitive to nitrogen oxide (NO x ) and SO 2 emissions in northern China, but to NO x and ammonia (NH 3 ) emissions in southern China. 30% NO x emission reductions may result in an increase in PM 2.5 concentrations in northern China because of the NH 3 -rich and volatile organic compound (VOC) limited conditions over this area. VOC emission reductions will lead to a decrease in PM 2.5 concentrations in eastern China. However, 30% reductions in the emissions of SO 2 , NO x , NH 3 , and VOC, individually or collectively, are insufficient to effectively mitigate the severe pollution over northern China. More aggressive emission controls, which needs to be identified in further studies, are needed in this area to reach the objective of 25% PM 2.5 concentration reduction in 2017 proposed in the Action Plan for Air Pollution Prevention and Control by the State Council in 2013. [ABSTRACT FROM AUTHOR]

A total of 13 diesel buses and 12 diesel trucks in Macao were tested using portable emission measurement systems (PEMS) including a SEMTECH-DS for gaseous emissions and a SEMTECH-PPMD for PM 2.5 . The average emission rates of gaseous pollutants and CO 2 are developed with the operating mode defined by the instantaneous vehicle specific power (VSP) and vehicle speed. Both distance-based and fuel mass-based emission factors for gaseous pollutants (e.g., CO, THC and NO X ) are further estimated under typical driving conditions. The average distance-based NO X emission of heavy-duty buses (HDBs) is higher than 13 g km −1 . Considering the unfavorable conditions for selective reductions catalyst (SCR) systems, such as low-speed driving conditions, more effective technology options (e.g., dedicated natural gas buses and electric buses) should be considered by policy makers in Macao. We identified strong effects of the vehicle size, engine displacement and driving conditions on real-world CO 2 emission factors and fuel consumption for diesel vehicles. Therefore, detailed profiles regarding vehicle specifications can reduce the uncertainty in their fleet-average on-road fuel consumption. In addition, strong correlations between relative emission factors and driving conditions indicated by the average speed of generated micro-trips are identified based on a micro-trip method. For example, distance-based emission factors of HDBs will increase by 39% for CO, 29% for THC, 43% for NO X and 26% for CO 2 when the average speed decreases from 30 km h −1 to 20 km h −1 . The mitigation of on-road emissions from diesel buses and trucks by improving traffic conditions through effective traffic and economic management measures is therefore required. This study demonstrates the important role of PEMS in understanding vehicle emissions and mitigation strategies from science to policy perspectives. [ABSTRACT FROM AUTHOR]

Abstract: China's air pollution control policies during the 12th Five Year Plan (2011–2015) are characterized by the targets of 10% nitrogen oxides (NO x ) reduction and 8% sulfur dioxide (SO2) reduction from the 2010 levels. In this study, the Community Multi-scale Air Quality (CMAQ) modeling system was used to evaluate the impact of only SO2, only NO x , and joint SO2/NO x control measures on particulate matter pollution, the greatest concern for urban air quality in China. Four emission scenarios were developed for 2015, including a business-as-usual scenario, a reference NO x control scenario based on the governmental plan, an accelerated NO x control technology scenario, and a scenario assuming joint controls of NO x and SO2 based on the governmental plan. Under the planned NO x control measures, the annual mean concentrations of particulate matter less than or equal to 2.5 μm (PM2.5) decline by 1.5–6 μg m−3, i.e. 1.6%–8.5%, in the majority of eastern China. The largest reduction occurs in the middle reach of the Yangtze River. Under accelerated NO x control measures, the annual average PM2.5 concentration reductions (compared with the business-as-usual scenario) in eastern China are 65% higher than the reductions under planned control measures. The unusual increase of PM2.5 concentrations in the North China Plain and the Yangtze River Delta during January after the reductions of NO x emissions was an integrated effect of excessive NO x , the ammonia-rich inorganic aerosol chemistry, and the non-methane volatile organic compounds (NMVOC) sensitive photochemical regime. Under the joint controls of NO x and SO2, the annual mean PM2.5 concentrations decline over 3 μg m−3, i.e. 3.2%–13%, in the majority of eastern China, and some areas in the middle reach of the Yangtze River have reductions as large as 6–8.3 μg m−3, i.e. 5.0%–13%. The average PM2.5 concentration reductions in eastern China are 1.20 μg m−3, 3.14 μg m−3, 3.57 μg m−3, 4.22 μg m−3 in January, May, August, and November, respectively. The corresponding declining rates are 2.3%, 12.2%, 14.3%, and 8.1%, respectively. More stringent policies should be implemented in winter to reduce the heavy pollution periods. The annual average PM2.5 concentration reductions in three major city clusters are comparable with the average reductions of eastern China. Stringent regional control policies are required for the significant improvement of particulate air quality in major city clusters. [Copyright &y& Elsevier]

Abstract: In recent years, heavy metal pollution accidents were reported frequently in China. The atmospheric heavy metal pollution is drawing all aspects of attention. This paper summarizes the recent research results from our studies and previous studies in recent years in China. The level, temporal variation, seasonal variation and size distribution of the heavy metals of atmospheric Lead(Pb), Vanadium(V), Manganese(Mn), Nickel(Ni), Chromium(Cr), Cadmium(Cd), Copper(Cu), Zinc(Zn) and Arsenic(As) were characterized in China. The emission characteristics and sources of atmospheric heavy metals and As in China were reviewed. Coal burning, iron and steel industry and vehicle emission are important sources in China. Control policies and effects in China were reviewed including emission standards, ambient air quality standards, phase out of leaded gasoline and so on, and further works for atmospheric heavy metals control were suggested. The comprehensive heavy metals pollution control measures and suggestions were put forward based on the summarization of the development and experience of the atmospheric heavy metal pollution control abroad. [Copyright &y& Elsevier]

Abstract: Halocarbon emissions from China are of great interest to both policy makers and academia. To estimate halocarbon emissions with interspecies correlation methods, previous studies adopted CO, HCFC-22 or other species as reference tracers. However, few of these studies compared the results using different reference tracers. In this study, chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons (HFCs) and carbon monoxide (CO) concentrations were measured at a monitoring site in northern China in 2009/2010, and halocarbon emissions were estimated using an interspecies correlation method. A comparison was performed of the correlations between estimated halocarbon emissions and two reference tracers, CO and HCFC-22. The results show that both species are significantly correlated with most of the target species (P < 0.01), whereas HCFC-22 shows better correlations than does CO. Our estimated halocarbon emissions for 2009 agree within uncertainties with results obtained with other approaches, including inverse modeling and interspecies correlation methods. The emissions for 2001–2009 estimated in different studies (all using top–down approaches) show a clear decrease in the emissions of CFC-11 and CFC-12 and an increase in the emissions of HCFC-22, HCFC-141b and HCFC-142b in China. Moreover, the combined Ozone Depletion Potential weighted emissions of CFCs are much greater than the reported consumption, whereas the emissions of HCFC counterparts are not more than one-half of the reported consumption. This result suggests that HCFCs are being accumulated in banks and that these banks will sustain elevated in China. [Copyright &y& Elsevier]