Yanjun Wang

With increasingly stringent international limits on diesel particulate matter emissions, Continuous-Regeneration Particulate Filters (CRPFs) have been widely applied in heavy-duty vehicle (HDV) exhaust systems. However, their impacts on the complete gaseous pollutant profile remain insufficiently characterized. This study investigated the effects of three CRPF configurations on gaseous emissions from a China III diesel engine under the World Harmonized Transient Cycle (WHTC). Regulated pollutants (CO, total hydrocarbons (THC), NOx, and CO₂) and unregulated pollutants (benzene series compounds and aldehydes) were measured before and after CRPF installation. The results demonstrated that CRPFs achieved high reduction efficiencies for CO (98.5–99.9%) and THC (77.4–99.9%) through catalytic oxidation, while showing negligible effects on NOx (0.2–3.0% reduction) and slight increases in CO₂ (0.07–0.55%). For unregulated pollutants, aldehydes were effectively reduced (formaldehyde: 84.1–100.0%; acetaldehyde: 47.4–100.0%), whereas benzene series compounds exhibited variable responses, with some species showing increased emissions. These findings reveal complex pollutant transformation mechanisms within CRPF systems and provide references for optimizing aftertreatment configurations to meet China VI and subsequent emission standards, thereby contributing to the mitigation of air pollution, the protection of public health, and the promotion of sustainable societal development.

Carbon emissions are currently a hot topic in the international community. CO₂ reduction from heavy-duty commercial vehicles plays a significant role in slowing down the global greenhouse effect and promoting sustainable development. To control carbon emissions, many countries have tightened CO₂ emission regulations and policy requirements for heavy-duty commercial vehicles in recent years. Various CO₂ emission simulation models have been developed, such as the Greenhouse Gas Emissions Model (GEM) in the United States and the Vehicle Energy Consumption Calculation Tool (VECTO) in the European Union, to evaluate the real CO₂ emission levels of commercial vehicles and provide a scientific basis for formulating corresponding emission reduction policies and control measures. This paper systematically analyzes the CO₂ emission regulations and policy requirements for heavy-duty commercial vehicles in the United States, the European Union, China, and other developed countries. It also analyzes the GEM software in the United States, the VECTO software used in Europe, and the energy consumption simulation software for commercial vehicles in China. The influencing factors of CO₂ emission simulation are explored in detail. This study found that, although GEM and VECTO software are recognized for their high accuracy, their applications are still dependent on local policies. In other countries and regions, VECTO software has broader applicability. On the other hand, China’s commercial vehicle energy consumption simulation software and other reported studies have only been validated for specific vehicle types. The accuracy and generalizability of these models should be further promoted and verified.

With the rapid development of industrialization and urbanization in China, civil aviation plays an increasingly important role in the transportation industry. However, pollutants and greenhouse gas (GHG) emissions from civil aviation are becoming an increasingly concerning environmental problem. In order to mitigate the resulting environmental pollution, such as air quality deterioration, regional and global climate warming, and declining human health, more and more efforts have been devoted to reducing both pollutants and GHG emissions. Among these efforts, emissions inventories from civil aviation provide a basis for quantifying pollutants and GHG emissions, establishing evaluation standards of environmental impact, and formulating management policies for both air quality improvement and climate change mitigation. In this paper, we reviewed both compilation approaches and data collection methods for civil aviation emissions inventories, introduced several typical calculation methods for aviation emissions inventories, and analyzed specific cases of actual application based on typical methods of inventory compilation. We also described in detail the activity level and emission index calculation methods of several pollutants and greenhouse gases. Furthermore, based on the above research methods, four typical application cases were investigated, including a specific airport, the landing and takeoff (LTO) cycle of a nation, the entire period with the LTO cycle and the climb–cruise–descent (CCD) phase of a country, and global emissions inventories from civil aviation. The results suggest that, in addition to quantifying the emissions of both pollutants and GHG produced by civil aviation, the selection of inventory compilation methods is likely to be important for improving aviation emission inventory accuracy and for further reducing the environmental, economic, and health impacts resulting from aviation emissions. Moreover, this paper can also provide a reference and theoretical basis for the development of aviation emission inventory compilation methods in the future.

The adoption of new energy vehicles (NEVs) is an effective strategy for pollution reduction, especially for high-emitting commercial vehicles. This paper systematically reviews the promotion policies and development status of zero-emission commercial vehicles (ZECVs) in China, with a focus on diverse application scenarios. Comprehensive policies, including subsidies, right-of-way, infrastructure development, and environmental protection incentives, have significantly advanced NEV adoption, as demonstrated by Shenzhen’s full electrification of buses and the extensive deployment of zero-emission trucks. Despite the overall slow development of ZECVs, regions in southern China and developed areas exhibit better progress. Medium and large passenger vehicles (MLPVs) have achieved a zero-emission rate of around 40%, contrasting with the significantly lower rates of 1.52% for mini and light trucks (MLTs) and 0.44% for medium and heavy trucks (MHTs). Electrification promotion varies significantly in different application scenarios, with buses leading at over 90% zero-emission rates, followed by the airport (24%) and port (16%) vehicles. The electrification of sanitation, logistics, and key industry transport, through lagging, is enhanced by targeted policies and local industry. Buses are designated as the highest priority (Level 1) for electrification transition while intercity logistics and vehicles in key industries are categorized as the lowest priority (Level 4). In addition, policy recommendations, including tailored strategies for ZECV promotion and emission reductions in traditional commercial vehicles, are put forward to provide guidance and reference for setting future zero-emission promotion goals and policy direction for commercial vehicles in subdivided application scenarios.

Motor vehicle exhaust is an important cause of atmospheric pollution. Nowadays, mainstream exhaust emission aftertreatment technologies, such as TWC, DOC, SCR, and DPF, usually require sufficient temperature to perform good purification or maintain normal working conditions. Compared with exhaust gas heating technologies such as engine enrichment and fuel injection, electric heating technology can quickly increase the temperature of exhaust gas aftertreatment devices without adverse effects on engine operating conditions. This article introduces the research and progress of electric heating technology combined with traditional aftertreatment devices on major types of vehicles, such as gasoline vehicles, diesel vehicles, motorcycles, and hybrid vehicles, to improve exhaust purification efficiency and its accompanying fuel consumption impact. In addition, the common structure and characteristics of electric heaters, as well as the current status and development trend of electric heating unit technologies such as electric heating power supply are introduced.

To meet more and more stringent emission standards, the combined technologies must be used to purify the emission pollutants of vehicle exhaust. Among them, the aftertreatment devices, including DOC, SCR, DPF, and so on, are the most efficient methods. However, after long-term running, the performance of the aftertreatment devices will inevitably degrade. There are several mechanisms that can be used to explain the aging phenomena. For the catalytic devices, such as DOC and SCR, thermal aging and poisoning aging are the most important reasons for their performance deterioration. As for DPF, ash clogging is a key problem for its stable working. To develop and test aftertreatment devices better and faster, the accelerated aging methods must be researched and applied. The small-sample aging method enables accelerated aging of catalyst samples at a very low cost, but its aging accuracy may not be good enough. Although the results of the whole-vehicle aging method and bench engine aging method are more in accord with the real using course, they take too much time and are too expensive to be used widely. Burner aging is a promising way to simulate the long-term running of the catalysts.