Diesel Particulate Matter Emissions Research Articles

The effect of multiple factors on water-soluble inorganic ions in diesel particulate matter emissions

The water-soluble inorganic ions (WSII) in diesel particulate matter (DPM) have a significant impact on ambient air quality and human health. In this study, the 12 groups of bench tests were conducted to analyze the emission characteristics of two diesel engines, taking into account the influence of engine parameters, test cycle, fuel types, and after-treatment measures. Compared to conventional diesel, a blend of diesel with 5 % biodiesel resulted in a reduction of the WSII emission factors by 23.7–48.0 %. The emission factors of WSII decreased by 8.4 % after installing selective catalytic reduction (SCR). Dummy variable regression analysis was used to analyze the relationship between WSII and influencing factors. The emission factors of Na+, K+, and Ca2+ were mostly affected by the engine, potentially due to the use of coolants and lubricants containing metal oxides in the engine. The emission factors of NO3- were mainly affected by the test cycle. Techniques for order preference by similarity to ideal solution (TOPSIS) were used to analyze the priority of emission reduction technologies. The results indicated that SCR, biodiesel, and low-sulfur diesel could effectively reduce WSII. This study aims to explore the influence of multiple factors on WSII, providing valuable insights for future research on WSII in DPM.

Sensitivity analysis and prediction of diesel particulate matter emissions in Indian underground metalliferous mines using regression and machine learning algorithms

Understanding the accumulation and dispersion characteristics of diesel particulate matter (DPM) in the closed environment of the underground mines and identifying the factors affecting these concentrations enables the mining authorities to formulate effective mitigation techniques to provide a safe and healthy working environment for the miners. For achieving this, DPM concentrations of three Indian underground mines were studied with a focus on the prediction of DPM using regression and Machine Learning (ML) algorithms and comparing their prediction accuracy. Multivariate regression analysis (MVRA) and Artificial neural networks (ANN) were utilised to correlate DPM concentrations and site-specific factors including the distance from the exhaust, ventilating air velocity, and source emission concentration. The results indicate that the best correlations between DPM concentrations and site parameters could be established by ANN with an R2 value of 0.986, while MVRA exhibited an R2 value of 0.916. Additionally, DPM concentrations were found to be most sensitive to gallery air velocity with a sensitivity index of (-) 2.87. The critical wind velocity above which the DPM concentrations reached below the safe permissible limits was determined to be 1.65 m/s for given cross-sectional profiles.

Behavior of diesel particulate matter transport from subsidiary transportation vehicle in mine.

The aim of this study was to investigate thoroughly the diffusion and distribution of diesel particulate matter (DPM) discharged from a mine subsidiary transportation vehicle to improve the air quality in tunnels by reducing exhaust pollution and to propose targeted prevention measures. More specifically, the diffusion of DPM from a WC40Y shield carrier during its travel was examined in depth with numerical simulations. The results show that, under the current ventilation conditions, the airflow in the tunnel was insufficient for diluting the DPM discharged from the shield carrier during starting, accelerated traveling, and turning; this can be effectively addressed by increasing the ventilation rate to 1.8m/s. However, during high-velocity travel, the carrier was affected by the piston wind could not be diluted effectively by increasing ventilation rate. The velocity limit can lower the DPM concentration in the tunnel and alleviate DPM pollution from the shield carrier. To reduce DPM emissions, the travel velocity should be limited to 30km/h. Summary: Determine the optimal airflow velocity in the tunnel that ensures that the discharged DPM is effectively diluted during the travel of the shield carrier.

Assessing emission and power tradeoffs of biodiesel and n-Butanol in diesel blends for fuel sustainability

The use of renewable biodiesel and additives diversifies transportation fuel supply. Combustion tests on neat ultra-low sulfur No.2 diesel (D100) and its blends with biodiesel and the n-butanol additive were conducted to investigate environmental impacts and tradeoffs in engine emission and power output. The testing results show measurable changes in power output and engine emission, particularly in diesel particulate matter (DPM) size distribution and black carbon compositions. The binary diesel-biodiesel blend D80B20 (80% D100 and 20%B100 by volume) offers reduced PM and black carbon emission, but higher NOx in engine exhaust. Comparatively the tertiary diesel-biodiesel-butanol blend B15Bu5 (80% D100, 15% B100, and 5% Bu100 by volume) shows superior environmental tradeoff in the black carbon and NOx emission than D80B20. Both fuel blends suffer a 3.0–5.6% increase in brake-specific fuel consumption. At higher combustion temperature, the butanol-oxygenated diesel fuel produces DPMs of smaller size, higher number concentrations, greater OC fractions, and more amorphous black carbon particles. The peak DPM aerodynamic size dpmax for D80B20 and B15Bu5 blends is 0.20–0.32 μm, smaller than >0.40 μm dpmax for D100 and the 0.30 μm cut-off size of regular DPM filters. For an internal combustion engine capable of accommodating biodiesel and water fraction in the fuel mixture, the B15Bu5 blend offers a viable fuel alternative according to the comparative testing results. The use of biodiesel and butanol additive in petroleum diesel can decrease the DPM emission, while the undesired NOx formation in tradeoff can be managed through optimizing the tertiary composition of petroleum diesel, biodiesel, and fuel additives.

Notable reductions in blow-by and particle emissions during cold and hot start operations from a turbocharged diesel engine using oxygenated fuels

The present study explores a comprehensive investigation of diesel blow-by, particulate matter (PM), particulate number (PN) and nitrogen oxides (NOx) emissions for cold and hot start operations in a six-cylinder, turbocharged diesel engine. A wide range of oxygenated blends of fuel-bound oxygen ranging from ~4% to ~8% (wt%) was used in the study. A reference diesel was also used for the comparison of the emissions results with those of oxygenated blends. Waste cooking biodiesel and an oxygenate, diethylene glycol dimethyl ether (diglyme) having three times higher cetane number than diesel and high fuel-bound oxygen, was used to make the oxygenated blends for examining the effect of fuel oxygen on diesel blow-by, PM, PN and NOx emissions. Carbon monoxide (CO), total unburned hydrocarbon (THC) and carbon dioxide (CO2) emissions were not targeted in this investigation. Fuel energy rate, exergy rate and exergetic cost were also investigated in this study. The experimental results show, blow-by, both PM and PN emissions were reduced significantly with a penalty of NOx emissions with oxygenated blends compared to diesel fuel during both cold and hot start operations. The energy rate, exergy rate and exergetic cost with oxygenated blends reveal insignificant variations relative to diesel.

Emission Characteristics and Risk Assessment in an Industrial Metropolitan Area in Taiwan using the AERMOD Model

Abstract. Air toxics, also known as hazardous air pollutants (HAPs), have gained increased public awareness in recent years. Air toxics may be released from various sources, such as mobile sources, stationary sources, and fugitive emissions. This study investigated profiles of air toxics from mobile sources, stationary sources, and the operations in a port in an industrial metropolitan area in Taiwan. Six carcinogens, including benzene, formaldehyde, 1,3-butadiene, arsenic, 2,3,7,8-TCDD, and diesel particulate matter (DPM), were chosen as the target pollutants. The AERMOD model was applied to simulate the concentrations of the ambient air toxic species, and the concentrations were used to evaluate cancer risk. Cancer risk for each air toxic was also investigated to evaluate the potential impact on residents. The results of the emission estimation for the base year (2014) showed that the emissions of benzene, 1,3-butadiene, and formaldehyde could be mainly attributed to mobile sources in the study areas. The contributions, in order, were 86 %, 77 %, and 69 %. DPM emissions from port operations accounted for 76 %, and most of the arsenic (70 %) and 2,3,7,8-TCDD (99 %) were emitted from stationary sources, especially from the steel industry. Approximately 66 % and 32 % of the cancer risk of air toxics were contributed to the emissions from port operations and on-road vehicles, respectively, in this area, and approximately 1.4 % of the risk was contributed to stationary sources. DPM was the pollutant that posed the highest cancer risk among all six air toxics. It accounted for more than 80 % of the overall cancer risk, followed by 1,3-butadiene (10 %), benzene (4.7 %), formaldehyde (1.2 %), arsenic (0.7 %), and 2,3,7,8-TCDD (0.2 %). The dominant sources of DPM were ocean-going vessels and diesel trucks.

Novel biofuels derived from waste tyres and their effects on reducing oxides of nitrogen and particulate matter emissions

Abstract There are tons of waste tyres produced each year globally. Production of oil from the waste tyre not only manages the wastes but also produces fuels for compression ignition engines. In this investigation, a novel approach developed by Green Distillation Technologies in Australia was used to convert whole end of life tyres (ELTs) into carbon, steel, and tyre oil. The physicochemical properties of the tyre oil are similar to diesel fuel, and the fuel is miscible with diesel in any blended ratio. An engine experiment was conducted on a EURO IIIA diesel engine. All experiments were performed at constant speed and four different engine loads. Two blends (10% and 20%) of tyre oil were compared to reference diesel fuel. Exhaust emissions, including gaseous emissions, particulate matter (PM) and particulate number (PN) were investigated. The results indicate simultaneous reductions in both diesel PM and nitrogen oxides (NOx) emissions with the tyre oil blends when compared to diesel. NOx emissions were reduced by approximately 30% with both blends with respect to diesel. The reduction in PM and PN emissions were in the range of 35–60% and 5–20%, respectively. Carbon monoxide (CO) were increased by ∼ 10% compared to the reference diesel except at quarter load. Insignificant change in brake power (BP), brake mean effective pressure (BMEP) and brake thermal efficiency (BTE) were observe with the tyre oil blends. The engine remained compliant with its EURO IIIA guidelines during the use of the tyre oil blends. Based on the engine performance and emission result, the tyre oil could be alternative to traditional diesel fuel.

The Hidden Killer: Towards Regulating Railyard Diesel Particulate Matter Emissions in Oregon

The Hidden Killer: Towards Regulating Railyard Diesel Particulate Matter Emissions in Oregon

Characterization and comparison of oxidative potential of real-world biodiesel and petroleum diesel particulate matter emitted from a nonroad heavy duty diesel engine

Little is known regarding the oxidative potential of biodiesel particulate matter (PM) relative to diesel PM emitted from heavy duty diesel (HDD) nonroad engines generated in real-world occupational settings. The composition of biodiesel and diesel PM can include transition metals, polar, and nonpolar organic species which can increase oxidative potential via production of reactive oxygen species (ROS). Elevated ROS can lead to oxidative stress and induce antioxidant defense, inflammation, and toxicity. This study characterized the chemical composition of PM (water soluble organic carbon and elemental metals) collected in a real-world occupational setting. ROS production in a human epithelial cell line (BEAS-2B) treated with biodiesel and diesel PM extracts was compared to oxidative potential measured by an acellular dithiothreitol (DTT) assay. The oxidative potential (DTT consumption rate) of diesel PM was 21% greater than biodiesel PM at the highest treatment concentration (60 μg/mL), yet the ROS generated in vitro were similar between fuel types. Average concentrations of Cu, Cr and Zn were higher in diesel PM compared to biodiesel PM. Additionally, there was a significant correlation between DTT consumption and Cu in diesel PM (r = 0.98), but not B20 PM. There was a strong correlation between WSOC content in diesel PM and ROS generated in vitro (r = 0.83), but no correlation between WSOC content in biodiesel PM and ROS. Taken together, the results indicate the influence of fuel type on the chemical composition and oxidative potential of PM generated by a nonroad HDD engine operated at a recycling center. While acknowledging the potential influence of other species of interest not measured (i.e., quinones), real-world petroleum diesel PM emissions had higher oxidative potential compared to biodiesel PM suggesting that biodiesel use may reduce risk to human health.

A Dense Sensor Network to Characterize Community Exposure to Black Carbon

We developed a low-cost black carbon (BC) sensor and deployed over 100 of them as a connected air quality network in West Oakland, California. The West Oakland residential community is adjacent to port and rail facilities and surrounded by major freeways. As such, the community is affected by diesel particulate matter emissions from heavy-duty diesel trucks, locomotives, and ships associated with freight movement.In partnership with community stakeholders, we positioned BC sensors outside of residences and businesses, along truck routes and arterial streets, along the Port of Oakland boundary, and at upwind locations. We operated this first-of-its kind BC air quality network for 100 days in summer 2017 in conjunction with a complementary study of on-road air pollution mapping.Spatiotemporal patterns in BC concentrations in West Oakland are observed to be driven by truck activity within the community. Highest concentrations exist along truck routes, near trucking facilities, and around businesses that use trucks to transport goods and materials. Almost everywhere, BC concentrations are higher on week-days than weekend-days, as is truck activity. The community-average BC concentration matches well the concentration measured at a centrally located site operated by the Bay Area Air Quality Management District. However, on average, 75% of locations within the community are more polluted than the central monitoring site, with daytime average BC up to 1.75× higher. Daytime average BC concentrations along the Port of Oakland boundary and designated truck routes around the community are up to 3× higher than the central monitoring site average. Overnight, the spatial gradient within the West Oakland neighborhood diminishes, such that BC concentrations are more uniform. Areas downwind of the freeway, along the Port of Oakland boundary, and at some trucking facilities have persistent elevated BC concentrations in the evening and early morning hours.

Deriving fuel-based emission factor thresholds to interpret heavy-duty vehicle roadside plume measurements

ABSTRACTRemote sensing devices have been used for decades to measure gaseous emissions from individual vehicles at the roadside. Systems have also been developed that entrain diluted exhaust and can also measure particulate matter (PM) emissions. In 2015, the California Air Resources Board (CARB) reported that 8% of in-field diesel particulate filters (DPF) on heavy-duty (HD) vehicles were malfunctioning and emitted about 70% of total diesel PM emissions from the DPF-equipped fleet. A new high-emitter problem in the heavy-duty vehicle fleet had emerged. Roadside exhaust plume measurements reflect a snapshot of real-world operation, typically lasting several seconds. In order to relate roadside plume measurements to laboratory emission tests, we analyzed carbon dioxide (CO2), oxides of nitrogen (NOX), and PM emissions collected from four HD vehicles during several driving cycles on a chassis dynamometer. We examined the fuel-based emission factors corresponding to possible exceedances of emission standards as a function of vehicle power. Our analysis suggests that a typical HD vehicle will exceed the model year (MY) 2010 emission standards (of 0.2 g NOX/bhp-hr and 0.01 g PM/bhp-hr) by three times when fuel-based emission factors are 9.3 g NOX/kg fuel and 0.11 g PM/kg using the roadside plume measurement approach. Reported limits correspond to 99% confidence levels, which were calculated using the detection uncertainty of emissions analyzers, accuracy of vehicle power calculations, and actual emissions variability of fixed operational parameters. The PM threshold was determined for acceleration events between 0.47 and 1.4 mph/sec only, and the NOX threshold was derived from measurements where after-treatment temperature was above 200°C. Anticipating a growing interest in real-world driving emissions, widespread implementation of roadside exhaust plume measurements as a compliment to in-use vehicle programs may benefit from expanding this analysis to a larger sample of in-use HD vehicles.Implications: Regulatory agencies, civil society, and the public at large have a growing interest in vehicle emission compliance in the real world. Leveraging roadside plume measurements to identify vehicles with malfunctioning emission control systems is emerging as a viable new and useful method to assess in-use performance. This work proposes fuel-based emission factor thresholds for PM and NOx that signify exceedances of emission standards on a work-specific basis by analyzing real-time emissions in the laboratory. These thresholds could be used to prescreen vehicles before roadside enforcement inspection or other inquiry, enhance and further develop emission inventories, and potentially develop new requirements for heavy-duty inspection and maintenance (I/M) programs, including but not limited to identifying vehicles for further testing.

Time-Dependent Contaminant Transport in Ventilating Air from a Moving Source

A new method which combines the Eulerian, fixed control volume with a moving, Lagrangean flow channel is described for the solution of the conjugate, advection-diffusion problem for modeling transport processes of contaminant species. The transport model is presented as a conservative mass balance equation in a state-flux, species transport form in the space-time domain. A fully-implicit, general solution scheme is formulated with matrix operators in the space-time domain. The particular solutions for specific initial and boundary conditions and source term are constructed with the help of a single, inverse matrix operator, A-1, which has to be calculated only once for all possible particular problems. Although A-1 involves a large number constants, all are independent from the initial, boundary, and source term input vectors. The multi-level, state-flux, space-time (SFST) scheme brings a significant computational acceleration since A-1 has to be calculated only once, such as in mine ventilation cases involving long drifts with constant air flow velocities. Such application is shown in an example for analyzing the transport and concentration distributions of diesel particulate matter (DPM) in the ventilation air at the working area with the interactions between ventilation and a moving diesel loading machine. Comparison between simulation and in situ DPM monitoring results suggests that reliable evaluation of average exposure of DPM to mine workers may be accomplished directly from tailpipe DPM emission data, ventilation air velocity, and mine geometry with the use of the SFST model even in a highly dynamic working area, potentially reducing the need for real-time DPM monitoring.

DPM simulation in an underground entry: Comparison between particle and species models

The diesel particulate matter (DPM) emission from diesel powered equipment in underground mines can cause health hazards including cancer to the miners. The understanding of the DPM propagation pattern under realistic mining condition is required for selecting proper DPM control strategies and to improve working practices in underground mines. In this paper, three dimensional simulations of DPM emission from the exhaust tail pipe of a load-haul-dump (LHD) vehicle and its subsequent distribution inside an isolated zone in the typical underground mine are carried out using two different solution models available in Ansys Fluent. The incoming fresh air into the isolated zone is treated as a continuous phase and DPM is treated either as a continuous phase (gas) or as a secondary discrete phase (particle). Species transport model is used when DPM is treated as gas and discrete phase model is used when DPM is assumed to behave like a particle. The distributions of DPM concentration inside the isolated zone obtained from each method are presented and compared. From the comparison results, an accurate and economical solution technique for DPM evaluation can be selected.

Diesel particulate matter and coal dust from trains in the Columbia River Gorge, Washington State, USA

We examined the emissions of diesel particulate matter (DPM) and coal dust from trains in the Columbia River Gorge (CRG) in Washington State by measuring PM1, PM2.5, CO2, and black carbon (BC) during the summer of 2014. We also used video cameras to identify the train type and speed.During the two-month period, we identified 293 freight trains and 74 coal trains that gave a PM2.5 enhancement of more than 3.0 μg/m3. We found an average PM2.5 enhancements of 8.8 and 16.7 μg/m3, respectively, for freight and coal trains. For most freight trains (52%), and a smaller fraction of coal trains (11%), we found a good correlation between PM2.5 and CO2. Using this correlation, we calculated a mean DPM emission factor (EF) of 1.2 gm/kg fuel consumed, with an uncertainty of 20%.For four coal trains, the videos revealed large plumes of coal dust emanating from the uncovered coal cars. These trains also had the highest peak PM2.5 concentrations recorded during our study (53–232 μg/m3). Trains with visible coal dust were observed for 5.4% of all coal trains, but 10.3% when the effective wind speed was greater than 90 km/h. We also found that nearly all coal trains emit coal dust based on (1) statistically higher PM2.5 enhancements from coal trains compared to freight trains; (2) the fact that most coal trains showed a weak correlation between PM2.5 and CO2, whereas most freight trains showed a strong relationship; (3) a statistically lower BC/PM2.5 enhancement ratio for coal trains compared to freight trains; and (4) a statistically lower PM1/PM2.5 enhancement ratio for coal trains compared to freight trains. Our results demonstrate that, on average, passage of a diesel powered open-top coal train result in nearly twice as much respirable PM2.5 compared to passage of a diesel-powered freight train.

Individual and population intake fractions of diesel particulate matter (DPM) in bus stop microenvironments

Diesel particulate matter (DPM) is associated with adverse human health effects. This study aims to investigate the relationship between DPM exposure and emissions by estimating the individual intake fraction (iFi) and population intake fraction (iFp) of DPM. Daily average concentrations of particulate matter at two bus stops during rush hours were measured, and then they were apportioned to DPM due to heavy-duty diesel bus emissions using Chemical Mass Balance Model. The DPM emissions of diesel buses for different driving conditions (idling, creeping and traveling) were estimated on the basis of field observations and published emission factors. The median iFi of DPM was 0.67 and 1.39 per million for commuters standing at the bus stop and pedestrians/cyclists passing through the bus stop during rush hours, respectively. The median iFp of DPM was 94 per million. Estimations of iFi and iFp of DPM are potentially significant for exposure assessment and risk management.

Hydrogen-reduced Cu/ZnO composite as efficient reusable catalyst for diesel particulate matter oxidation

Hydrogen-reduced copper-loaded ZnO (Cu/ZnO) showed a strong diesel particulate matter oxidation activity at temperature as low as 150°C. Cu/ZnO catalyst with 5% nominal Cu content was tested for the oxidation of diesel particulate matter under air flow between 25 and 800°C. The high catalytic performance of reduced 5%Cu/ZnO even after its use in diesel particulate matter oxidation has been assigned to the presence of Cu1+ ions at its surface, determined by Auger electronic spectroscopy. The high stability of Cu1+ could be assigned to the isoelectronic interaction of Cu1+ (3d10) with Zn2+ (3d10) at the Cu2O–ZnO interface. Results presented in this work indicate that the composite catalyst can be considered as part of an exhaust catalytic system, for abating diesel particulate matter emission at low temperature.

Diesel particulate matter emission factors and air quality implications from in–service rail in Washington State, USA

We sought to evaluate the air quality implications of rail traffic at two sites in Washington State. Our goals were to quantify the exposure to diesel particulate matter (DPM) and airborne coal dust from current trains for residents living near the rail lines and to measure the DPM and black carbon emission factors (EFs). We chose two sites in Washington State, one at a residence along the rail lines in the city of Seattle and one near the town of Lyle in the Columbia River Gorge (CRG). At each site, we made measurements of size–segregated particulate matter (PM1, PM2.5 and PM10), CO2 and meteorology, and used a motion–activated camera to capture video of each train for identification. We measured an average DPM EF of 0.94g/kg diesel fuel, with an uncertainty of 20%, based on PM1 and CO2 measurements from more than 450 diesel trains. We found no significant difference in the average DPM EFs measured at the two sites. Open coal trains have a significantly higher concentration of particles greater than 1μm diameter, likely coal dust. Measurements of black carbon (BC) at the CRG site show a strong correlation with PM1 and give an average BC/DPM ratio of 52% from diesel rail emissions. Our measurements of PM2.5 show that living close to the rail lines significantly increases PM2.5 exposure. For the one month of measurements at the Seattle site, the average PM2.5 concentration was 6.8μg/m3 higher near the rail lines compared to the average from several background locations. Because the excess PM2.5 exposure for residents living near the rail lines is likely to be linearly related to the diesel rail traffic density, a 50% increase in rail traffic may put these residents over the new U.S. National Ambient Air Quality Standards, an annual average of 12μg/m3.

Air-fraction modeling for simultaneous Diesel engine NOx and PM emissions control during active DPF regenerations

This study develops a control-oriented air-fraction model which can accurately predict the air-fraction dynamics for a Diesel engine and the coupled aftertreatment system (mainly Diesel oxidation catalyst (DOC)) during active DPF regenerations. NOx and particulate matter (PM) emissions are the two main concerns for modern Diesel engine development. Diesel particulate filters (DPFs) have become a standard device for reducing the PM emissions from Diesel engine powertrains. To maintain high filtration efficiencies and avoid high back pressures, active DPF regenerations have to be implemented periodically by significantly elevating the exhaust gas temperatures. However, during active DPF regenerations, the selective catalytic reduction (SCR) deNOx performance may be significantly decreased, while the high temperature durability and total hydrocarbon (THC) poisoning of SCRs may be potential issues. To simultaneously meet the NOx emission standard, high-pressure loop EGR needs to be applied. Since in-cylinder NOx reduction relies heavily on the in-cylinder oxygen content, an accurate air-fraction model is necessary, and the effects of recycled THC and CO emissions should be considered. The developed air-fraction model has been experimentally validated to show its capability of capturing the actual air fraction dynamics accurately. Such a model can be instrumental in simultaneous NOx and PM emission control during active DPF regenerations and in advanced combustion mode control.

Predicting areas of high diesel particulate matter emissions in Phoenix, Arizona, using spatial analysis techniques

Growing evidence suggests that inhalation exposure to diesel exhaust, including diesel particulate matter (DPM), causes acute and chronic health effects. As a result, interest in monitoring diesel exhaust has increased. Maps of emissions sources, emissions activity data, and meteorology were combined within a geographic information system (GIS) suitability model to produce a composite map identifying areas where DPM emissions are likely to be high. The results of the GIS model were compared with (i) the locations of existing monitoring sites in Phoenix, Arizona, and (ii) the spatial distribution of population. The results indicate that two existing sites are located in areas where DPM emissions are predicted to be high; however, incorporating meteorology as a factor showed that one site is located upwind of a predicted high DPM area. Consideration of population density showed high density in two areas that appear to be moderately influenced by DPM.

Soot Reduction Strategy: A Review

The aim of study is soot reduction strategy by using microwave radiation. As a first step toward the aim is a review. This study provides a review of soot particles generation and their influence on air pollution and illustrates the diesel particulate matter emission regulation, composition, and characterization including size, shape, process, and oxidation. The paper also discusses the effect of temperature, pressure, air/fuel ratio, exhaust flow rate, fuel type on soot process and heat release from soot combustion. The use of filter regeneration strategies for reducing soot emission from vehicles, stationary plants and factories due to the burning of diesel fuel have been presented with advantage and disadvantage of each method. The various strategies include catalyst, fuel injection, electric heating, engine operation condition control, non-thermal plasma, and absorbed microwave energy. The practical feasibility for soot oxidation by microwave heating technique has been explained depending on soot material property. The proposed new technique utilizing the reflected and absorbed energies of microwave for soot reduction strategy is presented to develop a new emission after-treatment system. The new system will be modeled and simulated using appropriate software. The simulation results will be validated experimentally. © 2012 Asian Network for Scientific Information.