Towards sustainable transport: quantifying and mitigating pollutant emissions from heavy-duty diesel trucks in Northeast China.

Heavy-duty diesel trucks (HDDTs) have caused serious environmental pollution in China. Accurate estimation of their pollutant emission characteristics is essential to reduce emissions and associated environmental and public health impacts. To achieve sustainable development for transport emissions in Northeast China, we developed localized emission factors and a high-resolution emission inventory of HDDTs, based on on-board test, Guidebook and international vehicle emission (IVE) model. The results show that the total emissions of CO, NO, NO2, and PM from HDDTs in Northeast China in 2020 were 172.2 kt, 531.5 kt, 11.2 kt, and 921.4 t, respectively. In terms of spatial distribution, emissions decreased from the city center to the city fringe. Temporally, the NOx emission variation curves of different types of roads presented a "single-peak" emission characteristic, which was different from the peak of traffic flow. Three emission reduction scenarios are further developed in the paper. Scenario analysis shows that elimination of HDDTs that follow the old China III emission standard and installing tailpipe treatment devices are the most effective pollutant reduction measure. The reduction percentages for CO, NO, NO2, and PM ranged from 62.9 to 83.89%. The results of our study could inform policymakers to devise feasible strategies to reduce vehicle pollution in Northeast China.

Substance flow analysis of arsenic and its discharge reduction in the steelworks.

Although certain emission standards have been implemented to reduce the air pollution from the steel industry, heavy metal pollution associated with steel production in China has not been well addressed yet. Arsenic is a metalloid element, commonly present in various compounds in many minerals. When it presents in steelworks, it not only affects the quality of steel products, but also causes environmental consequences such as soil degradation, water contamination, air pollution and associated biodiversity loss and public health risks. At present, most of the studies on arsenic were limited to its removal in a certain process, while there has not been a thorough analysis of the flow path of arsenic in steelworks that can facilitate a more efficient removal from its lifecycle. To achieve this, we established a model to depict arsenic flows in steelworks for the first time using adapted substance flow analysis. Then, we further analyzed arsenic flows in the steelworks using a case study in China. Finally, input-output analysis was applied to study the arsenic flow network and explore the reduction potential of arsenic-containing wastes in steelworks. The results show that: 1) the arsenic in the steelworks comes from inputs of iron ore concentrate (55.31 %), coal (12.71 %) and steel scrap (18.67 %), while the outputs were hot rolled coil (65.93 %) and slag (33.03 %). 2) The input, circulation, and final product content of arsenic are 96.120, 32.510, and 66.946 g/t-CS, respectively, and the recycling rate of arsenic was 48.28 %, in the steelworks. 3) The total arsenic discharge from the steelworks is 34.826 g/t-CS. 97.33 % of arsenic is discharged in the form of solid waste. 4) The reduction potential of arsenic in wastes is 14.31 % in the steelworks by adopting low-arsenic raw materials and removing arsenic from processes.

Assessment of different methods in analyzing motor vehicle emission factors.

To explore the emission characteristics of vehicle's pollutants is of great significance to prevent and control the diffusion of pollutants. Limited by geographic location and economic condition, the model- and guideline-based studies on vehicle's emission factor have become more concerned measures than the actual measurement. By analyzing the actual operating conditions of motor vehicles, this study obtains the emission factors of typical pollutants from different motor vehicles by adopting international vehicle emission (IVE) model and guideline method, respectively. Furthermore, the resulting emission factors by the above methods were compared and analyzed with on-road method. The results show that: (1) the emission factors of vehicle pollutants change regularly with velocity, emission standard, and accumulated mileage. Taking CO as an example, its emission factor shows a downward trend with the increase of velocity and emission standard and an upward trend with the increase of accumulated mileage; (2) compared with the actual measurement, the vehicle emission factor obtained by the guideline method has a large error, while the IVE model is close to the actual.

The changes in spatial layout of steel industry in China and associated pollutant emissions: A case of SO2.

The spatial layout of the steel industry has an impact on the regional atmospheric environment. In this study, the steel industry evolution model and the driving force analysis model were combined to analyze the evolution of spatial layout of the steel industry in China and the driving factors of this evolution. In addition, the WRF-SMOKE-CMAQ model was used to analyze the spatial dynamics of SO2 emissions from the steel industry. Our analysis presents the evolution of the steel industry in China in four stages: policy-determining, resource-oriented, economic promotion and market-oriented stage. The change in the spatial layout of the Chinese steel industry resulted in a continuously decreasing trend of pollutants in temporal characteristics and a decreasing share of emissions in North China and a continuous growth in East China in spatial characteristics. Our simulation shows that, by 2025, the pollutant SO2 emission concentration will migrate to the southeast, subject to market-oriented factors.

Comprehensive and high-resolution emission inventory of atmospheric pollutants for the northernmost cities agglomeration of Harbin-Changchun, China: Implications for local atmospheric environment management.

Using a bottom-up estimation method, a comprehensive, high-resolution emission inventory of gaseous and particulate atmospheric pollutants for multiple anthropogenic sectors with typical local sources has been developed for the Harbin-Changchun city agglomeration (HCA). The annual emissions for CO, NOx, SO2, NH3, VOCS, PM2.5, PM10, BC and OC during 2017 in the HCA were estimated to be 5.82 Tg, 0.70 Tg, 0.34 Tg, 0.75 Tg, 0.81Tg, 0.67 Tg, 1.59 Tg, 0.12 Tg and 0.26 Tg, respectively. For PM10 and SO2, the emissions from industry processes were the dominant contributors representing 54.7% and 49.5%, respectively, of the total emissions, while 95.3% and 44.5% of the total NH3 and NOx emissions, respectively, were from or associated with agricultural activities and transportation. Spatiotemporal distributions showed that most emissions (except NH3) occurred in November to March and were concentrated in the central cities of Changchun and Harbin and the surrounding cities. Open burning of straw made an important contribution to PM2.5 in the central regions of the northeastern plain during autumn and spring, while domestic coal combustion for heating purposes was significant with respect to SO2 and PM2.5 emissions during autumn and winter. Furthermore, based on Principal Component Analysis and Multivariable Linear Regression model, air temperature, relative humidity, electricity and energy consumption, and the urban and rural population were optimized to be representative indicators for rapidly assessing the magnitude of regional atmospheric pollutants in the HCA. Such indicators and equations were demonstrated to be useful for local atmospheric environment management.

Spatiotemporal analysis of anthropogenic phosphorus fluxes in China.

Anthropogenic phosphorus supports food systems while have caused water pollution and posed challenges to the ecosystems. The increasing socioeconomic interactions between regions and systems have added more complexities to manage the sustainability of effective phosphorus use that requires joint analyses of multiple regions or multiple systems of phosphorus flow. This study builds a framework to systematically model the phosphorus fluxes in China based on material flow analysis. This model consists of phosphorus industrial system, agricultural planting system, rural residential system, urban residential system, large-scale livestock breeding system and household livestock breeding system. This study further explored the temporal and spatial characteristics of phosphorus fluxes in terms of phosphorus utilization efficiency and water load during 1995-2015. The results showed that the total amount of phosphorus input in China had increased nearly 1.78 times during 1995-2015, of which about 85% is used for fertilizer production. The phosphorus utilization rates of urban residential and large-scale livestock breeding systems remained low with a declining trend, dropping to 5%. The phosphorus water load peaked and declined during the study period. Among them, the phosphorus water load in large-scale and household livestock breeding systems accounted for more than 60% of the total. In spatial dimension, Southwest China is the region with the largest input of phosphorus, about 375.33 × 104 t, while Northeast China is the region with the largest phosphorus water load, about 28.06 × 104 t.

Technologies-based potential analysis on saving energy and water of China's iron and steel industry.

Water and energy conservation are indispensable commitments to achieve the sustainable development of the iron and steel industry. Hereby, this study established an evaluation framework to model the water and energy consumption in the iron and steel industry. This framework quantitatively assessed the energy and water saving with adoption of conventional and emerging technologies. Thirty mainstream technologies, among which 21 focused on energy saving and the remaining 9 focused on water saving, were selected for analysis. Five scenarios were developed to examine systematic water- and energy-saving potentials, including benchmark (BM) scenario, constrained product (CP) scenario, business as usual (BAU) scenario, and benefit/cost-driven (BD) scenario and strengthened policy (SP) scenario. The results show that the energy-saving potentials of BAU, BD and SP scenarios are 1.75 PJ, 1.21 PJ and 1.65 PJ, respectively. The water-saving potentials of BAU, BD and SP scenarios are 4.83 billion m3, 5.71 billion m3 and 9.15 billion m3, respectively. The specific energy consumption and water consumption decreased to 15.01-15.59 GJ/t and 54.13-58.77 m3/t, respectively. This study suggested to implement encouraging policies in prompt popularity rate of technologies, and promote energy-saving and water-saving technologies to achieve sustainable development of iron and steel industry.

Comprehensive evaluation on energy-water saving effects in iron and steel industry.

The production of iron and steel is energy-intensive that motivated the emergence of various energy-saving technologies to reduce energy consumption. However, the effects of water-saving brought by these energy-saving technologies are rarely examined which can lead to misevaluation of their economic feasibility. In this regard, material flow analysis (MFA) was used in this study to establish the water-energy nexus and examine the potential of water-saving and energy-saving effects in the condition of applying various mixes of the 16 technologies (Ministry of Industry and Information Technology, 2015-2016) in iron and steel industry. Meanwhile, this study classified the selected 16 energy-saving technologies into three groups: direct water-saving technology, indirect water-saving technology, and water consumption technology. The low-temperature steel rolling technology is the only water-consuming energy-saving technology in this study; its indirect specific water computation reaches 0.06 m3/t. The remaining 15 energy-saving technologies have the potential of saving water indirectly, with averaged indirect specific water-saving amounting to 0.28 m3/t. This study also built an evaluation scheme of cost-benefit analysis for energy-saving technologies. With consideration of benefits brought by water saving, eleven technologies have the potential to achieve economic feasibility compared to nine in which mere energy-saving effects being considered. The results show that if the studied 16 technologies are implemented simultaneously, the comprehensive specific energy consumption will be reduced by 4.28 MJ, and the specific fresh water consumption will be reduced by 0.68 m3. Meanwhile, this research found that the cost of most energy-saving technologies will be decreased by an average of 5.52 CNY/GJ, despite the cost of low-temperature steel rolling technology increased by 0.68 CNY/GJ. This study evaluated the cost-effectiveness of energy-saving technologies taking the benefits of water conservation into consideration. It could provide references for decision-makers to develop commercialization strategies on energy saving technologies in the steel industry.