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Physical and chemical properties of aerosol, filter media properties, aerosol composition, dust cake properties, construction of filter unit, dew point and temperature are the parameters that affect the filtration performance during the control of industrial air pollution. No comprehensive experimental study has been reported on the effect of varying cleaning cycle times on the filtration performances, and no emission study at the clean side was conducted using PTFE-coated membrane on polyester needle punched filter media. In this experimental work, we are studying the filtration performances and characterization of emitted particles with varying cleaning cycle times in a pulse jet filtration system with membrane-coated media. The particulate emissions in terms of PM2.5 and PM10 are substantially lower, when using a coated membrane on filter media. Mass concentration and number concentration in downstream emission is also lower for filter media using PTFE membrane on needle felt nonwovens fabric media. Filtration efficiency is higher for filter media with PTFE coated than without PTFE membrane coating. PTFE membrane-coated media fabric exhibits lower residual pressure drop (∆P), which ultimately enhances the filter media life, more energy saving and better control on emissions. The downstream D10, D50, and D90 particles values are much higher in non-PTFE membrane-coated filter media. Overall, it is observed that fabric filter media with PTFE membrane, arrests a higher proportion of the fine particles, which causes lesser impacts on human health by industrial air pollution. Hence, the membrane-coated filter media (i.e. membrane separation) effectively controls the fine particles emission at downstream side/clean side. [ABSTRACT FROM AUTHOR]

In this work, we evaluated the impact of disc rotors of gray cast iron (GCI), nitrocarburized (NC), and superhard ceramic-coated (SCC) GCI on the brake wear PM emissions of passenger vehicles using dynamometric measurements. The brake emission factor (BEF) of the SCC was greatly reduced by more than a factor of 1/5 compared with those for the GCI and NC for both low-steel and non-steel friction materials. Surface topological and microstructural analyses confirmed that more severe wear was pronounced for the NC rotor compared with the SCC, as evidenced by large concave pits in the wear tracks. Analysis of the size-classified airborne PM suggests that reduced micron-sized particles, which originated from the GCI disc, were responsible for the lower BEF due to the increased hardness of the SCC. [ABSTRACT FROM AUTHOR]

The effect of progressive pulse cleaning pressure (2 bar to 3.5 bar) on filtration behaviour of two different polyester needle-punched nonwoven filter materials, viz. PTFE finished and without finished media has been studied at varying dust densities using flyash aerosol. The filter materials have been investigated on a flatbed filtration test rig based on cleaning at a fixed peak pressure drop of 1000 Pascal for an equal number of test cycles during the first three phases (conditioning, ageing and stabilizing phase) and further for the final measuring phase of four hours. The particulate emission and residual pressure drop behaviour are found to be significantly less in the case of PTFE-coated material under all the operating conditions. However, a significant difference among all levels of progressive pulse pressure has been found for both the examined materials. [ABSTRACT FROM AUTHOR]

Present study embodies filtration characterization of two nonwoven needle-felt polyester filter materials, viz. PTFE coated and without coated media. The materials have been assessed using flyash aerosol under varying time intervals (6, 9 and 12 min) at different inlet dust densities (50, 90 and 150 g/m3). The flyash particles are charged prior to their deposition over the filter media using a three phase parallel plate box pre-charger at two different levels of pre-charge, viz. 4 kV and 8 kV along with 0 kV. Results reveal that the filtration performance for PTFE coated material is better under all conditions. However, an enhanced filtration performance in terms of particle emission and pressure drop is noted at increased pre-charge level and higher cyclic interval. It may also be noted that the level of improvement in filtration behavior for both the materials has been better at initial level of pre-charge from 0 kV to 4 kV. However, the cumulative behavior of all the factors is also found significant. [ABSTRACT FROM AUTHOR]

Smouldering combustion can emit a large amount of CO2, CO and particulate matter (PM). Moisture content is an important factor of the emission characteristics. As the hot spot of forest smouldering combustion, the gas and particulate emissions of the Huzhong National Nature Reserve with different moisture contents are discussed herein. The emission factors (EF) of CO2 and CO were 100.71 ± 39.14 g/kg and 11.76 ± 3.89 g/kg, respectively. The EF of PM2.5, PM4 and PM10 were 87.11 ± 19.47 g/kg, 353.37 ±159.25 g/kg and 602.59 ± 276.80 g/kg, respectively. PM2.5 accounted for 16.59 ± 5.25% of the PM, and PM4 and PM10 were 54.03 ± 13.46% and 91.00 ± 10.81%, respectively. There was no significant difference in the EF of CO2 and CO with different moisture contents, nor in the EF of PM2.5, but there was a significant difference in the EF of PM4 and PM10 with different moisture contents. In addition, the peak of CO2 and CO appeared at 2~3 h; the peak of PM2.5 lagged behind that of PM4 and PM10. According to the regression analysis, experimental expressions were obtained for the modified combustion efficiency (MCE) and the EF of PM. [ABSTRACT FROM AUTHOR]

In this work, we evaluated the impact of disc rotors of gray cast iron (GCI), nitrocarburized (NC), and superhard ceramic-coated (SCC) GCI on the brake wear PM emissions of passenger vehicles using dynamometric measurements. The brake emission factor (BEF) of the SCC was greatly reduced by more than a factor of 1/5 compared with those for the GCI and NC for both low-steel and non-steel friction materials. Surface topological and microstructural analyses confirmed that more severe wear was pronounced for the NC rotor compared with the SCC, as evidenced by large concave pits in the wear tracks. Analysis of the size-classified airborne PM suggests that reduced micron-sized particles, which originated from the GCI disc, were responsible for the lower BEF due to the increased hardness of the SCC.

Both the EU and China are evaluating the feasibility of lowering the detection limit of particle number (PN) measurement to 10 nm in future legislations, making it necessary to better understand the sub-23 nm particle emission characteristics from state-of-the-art vehicles. In this study, solid PN emissions with a diameter larger than 10 nm and 23 nm (known as SPN10 and SPN23) were compared over the WLTC, RTS95, and a so-called "worst-case" real driving emission (RDE) cycle (highly dynamic/0 °C) using two certification-level particle number counters (PNCs) employing evaporation tube (ET) and catalytic stripper (CS) as volatile particle remover (VPR). The results show that SPN10 emissions were 31.7%, 27.8%, and 15.2% higher than SPN23 over the WLTC, RTS95, and laboratory RDE cycles. Sub-23 nm particles were almost not identified within the engine cold-start phase and tended to be a hot-running pollutant favored by aggressive driving styles (frequent accelerations and high engine loads), fuel-cut during decelerations, and long idles. Lower testing temperature delayed the light-off of catalyst and, therefore, significantly reduced the formation of sub-23 nm particles within the engine warm-up stage. Lowering the detection limit to 10 nm is deemed to provide more public health protection since it will guide manufacturers to pay more attention to vehicle hot-running emissions. [ABSTRACT FROM AUTHOR]

Abstract In this article, in order to optimize diesel aftertreatment system with periodically reciprocating flow (PRF), an experimental study is conducted to investigate its characteristics such as pollution emissions, regeneration of diesel particulate filter (DPF), concentration, and size distribution of particulate matter (PM) escaped as well as temperature distribution under unidirectional flow and PRF operating conditions. The effects of reciprocating flow cycle and exhaust gas flow on the performance of aftertreatment system are investigated in detail. The energy efficiency analysis of the aftertreatment system is also carried out. Experimental results show that (a) as the temperature is lower than the light‐off threshold of combustible gas, the aftertreatment system cannot restrain the formation of second particles under the low‐temperature condition of unidirectional flow; and (b) the aftertreatment system demonstrates excellent performance of trapping particles and filter regeneration as the symmetrical temperature distribution is formed. The PM filter efficiency αPM is 92%, and the specific energy consumption β is 124% for symmetrical temperature distribution; (c) the increase in reciprocating flow cycle could lead to the shifting of the temperature profiles, and this would affect the particle size distribution; (d) a certain increase in exhaust gas flow from engine would have insignificant change for the temperature distribution; and (e) the critical energy efficiency ηc of the system could reach 96.61%.

Using straw and herbaceous crops to replace or augment fossil fuels is becoming popular as access to forest biomass becomes environmentally stricter and more expensive. The low bulk density raw biomass is pre-processed and densified into pellets to facilitate handling and use. Dust is generated during collection, baling and debaling, grinding, drying, and densifying processed herbaceous biomass. Abundant literature deals with dust generated during the industrial handling of woody biomass, grains, and other crops like cotton. But the information on handling herbaceous biomass in the open literature is scarce. This paper reviews the available literature on dust generation from handling and processing of herbaceous biomass. Limited available data shows that herbaceous biomass species have a lower ignition temperature than woody biomass. The paper identifies several crucial pieces of information needed to ensure safety in the handling and pelleting of herbaceous crops. [ABSTRACT FROM AUTHOR]

The emission of particulate matter (PM) from agricultural activities, such as concentrated animal feeding, straw combustion, and mechanized harvest, is a hot issue in the sustainable development of agriculture, which has attracted more and more attention from government departments and researchers. However, the research on the transport of particulate matter in the agri-environment still lacks flexible and efficient measurement methods to obtain real-time and accurate spatial distribution data. The objective of our study is to produce a new intelligent platform for agri-environment atmospheric monitoring with high mobility, temporal and spatial resolution, and remote data transmission function to overcome the shortcomings of traditional atmospheric particulate matter monitoring stations, such as small particle size range, immovability, and high cost. Through the light scattering sensor, microcontroller, and wireless data transmission device assembled on the high-mobility drone, the platform could measure the mass concentration of PM2.5, PM10, and TSP at different spatial points in the agri-environment and transmit the measurement data to the receiving device on the ground through three modes: CLOUD, TCP, and UDP. We also developed monitoring software based on the Android platform, which could complete the connection of device and real-time monitoring of measurement data on the ground. Compared with stationary measurement devices, the biggest advantage of our mobile monitoring system is that it has the ability to measure the concentration of TSP and the vertical distribution of PM, which is very important for the research of agricultural environmental particulate matter emission characteristics. After the sensor and communication performance experiments, the sensors had high consistency in the overall change trend, and the communication accuracy rate was high. We carried out a flight measurement comparison experiment at the Wenhua Road Campus of Henan Agricultural University, and the measurement data were highly consistent with the data from the national monitoring stations. We also conducted an agri-environmental atmospheric measurement experiment in Muzhai Village and obtained the vertical distribution data of PM concentration at the nearby measuring point when the harvester was working. The results showed that after the harvester worked for a period of time, the PM2.5, PM10, and TSP concentrations reached the maximum at the altitude of 20 m at the measurement point, which were 80, 198, and 384 μg/m3, respectively, 2.64~3.10 times the particle concentration in the environment before the harvester began to work. Our new platform had high mobility, sensitive reading, and stable communication during the experiment, and had high application value in agricultural environmental monitoring.

Both the EU and China are evaluating the feasibility of lowering the detection limit of particle number (PN) measurement to 10 nm in future legislations, making it necessary to better understand the sub-23 nm particle emission characteristics from state-of-the-art vehicles. In this study, solid PN emissions with a diameter larger than 10 nm and 23 nm (known as SPN10 and SPN23) were compared over the WLTC, RTS95, and a so-called “worst-case” real driving emission (RDE) cycle (highly dynamic/0 °C) using two certification-level particle number counters (PNCs) employing evaporation tube (ET) and catalytic stripper (CS) as volatile particle remover (VPR). The results show that SPN10 emissions were 31.7%, 27.8%, and 15.2% higher than SPN23 over the WLTC, RTS95, and laboratory RDE cycles. Sub-23 nm particles were almost not identified within the engine cold-start phase and tended to be a hot-running pollutant favored by aggressive driving styles (frequent accelerations and high engine loads), fuel-cut during decelerations, and long idles. Lower testing temperature delayed the light-off of catalyst and, therefore, significantly reduced the formation of sub-23 nm particles within the engine warm-up stage. Lowering the detection limit to 10 nm is deemed to provide more public health protection since it will guide manufacturers to pay more attention to vehicle hot-running emissions.

In this article, in order to optimize diesel aftertreatment system with periodically reciprocating flow (PRF), an experimental study is conducted to investigate its characteristics such as pollution emissions, regeneration of diesel particulate filter (DPF), concentration, and size distribution of particulate matter (PM) escaped as well as temperature distribution under unidirectional flow and PRF operating conditions. The effects of reciprocating flow cycle and exhaust gas flow on the performance of aftertreatment system are investigated in detail. The energy efficiency analysis of the aftertreatment system is also carried out. Experimental results show that (a) as the temperature is lower than the light‐off threshold of combustible gas, the aftertreatment system cannot restrain the formation of second particles under the low‐temperature condition of unidirectional flow; and (b) the aftertreatment system demonstrates excellent performance of trapping particles and filter regeneration as the symmetrical temperature distribution is formed. The PM filter efficiency αPM is 92%, and the specific energy consumption β is 124% for symmetrical temperature distribution; (c) the increase in reciprocating flow cycle could lead to the shifting of the temperature profiles, and this would affect the particle size distribution; (d) a certain increase in exhaust gas flow from engine would have insignificant change for the temperature distribution; and (e) the critical energy efficiency ηc of the system could reach 96.61%. [ABSTRACT FROM AUTHOR]

Using straw and herbaceous crops to replace or augment fossil fuels is becoming popular as access to forest biomass becomes environmentally stricter and more expensive. The low bulk density raw biomass is pre-processed and densified into pellets to facilitate handling and use. Dust is generated during collection, baling and debaling, grinding, drying, and densifying processed herbaceous biomass. Abundant literature deals with dust generated during the industrial handling of woody biomass, grains, and other crops like cotton. But the information on handling herbaceous biomass in the open literature is scarce. This paper reviews the available literature on dust generation from handling and processing of herbaceous biomass. Limited available data shows that herbaceous biomass species have a lower ignition temperature than woody biomass. The paper identifies several crucial pieces of information needed to ensure safety in the handling and pelleting of herbaceous crops.

Abstract Accurate estimation of particulate emissions is fundamental to assessing the air quality risks posed by existing and proposed open cut black coal mines. The currently available emission estimation techniques are based on a limited range of empirical studies, and the need for additional research and development of activity and region specific particulate emission estimation methods has been recognised. This paper presents the results of empirical testing of particulate emission rates for open area surfaces in open cut black coal mines in three Australian regions. The emission rates are provided for specific wind speeds, thus allowing adjustment of emission rates for prevailing meteorology in these regions. The influence of surface watering as a control technique is also considered. Particulate emission rates are presented for a range of coal mining sources, and for specific wind speeds. Comparison of the emission rates with the existing published research confirms the emission rates are consistent with current approaches. This research significantly expands our current understanding by presenting emission rates for a range of open area sources, for specific wind speeds and surface watering controls. This more detailed emission estimation dataset provides for adjustments to default particulate emission rates to allow site specific data to be integrated into emissions estimation. This will result in more accurate emissions estimates for existing and future projects and reduce the potential for significant over- or under-estimation of particulate emissions from surface sources in open cut coal mines. Graphical abstract Image Highlights • Particulate emission rates from open cut coal mines were experimentally challenged. • Results enable regional adjustments of emission rates for prevailing meteorology. • The influence of surface watering as emission control technique was also considered. • More accurate emission estimates for existing and future projects will be possible. [ABSTRACT FROM AUTHOR]

In the past several decades, biofuels have emerged as candidates to help mitigate the issues of global warming, fossil fuel depletion and, in some cases, atmospheric pollution. To date, the only biofuels that have achieved any significant penetration in the global transportation sector are ethanol and biodiesel. The global consumption of biodiesel was rapidly increased from 2005. The goal of this study was to examine the chemical composition on particulate pollutant emissions from a diesel engine operating on several different biodiesels. Tests were performed on non-road diesel engine. Experiments were performed on 5 different fuel blends at 2 different engine loading conditions (50% and 75%). 5 different fuel blends were ultra-low sulfur diesel (ULSD, 100%), soy biodiesel (Blend 20% and Blend 100%) and canola biodiesel (Blend 20% and Blend 100%). The chemical properties of particulate pollutants were characterized using an Aerodyne High Resolution Time of Flight Aerosol Mass Spectrometer (HR-ToF-AMS). Organic matter and nitrate were generally the most abundant aerosol components and exhibited maximum concentration of 1207 μg/m3 and 30 μg/m3, respectively. On average, the oxidized fragment families (CxHyO1+, and CxHyOz+) account for ~13% of the three family sum, while ~87% comes from the CxHy+ family. The two peaks of C2H3O2 (m/z 59.01) and C3H7O (m/z 59.04) located at approximately m/z 59 could be used to identify atmospheric particulate matter directly to biodiesel exhaust, as distinguished from that created by petroleum diesel in the AMS data.

In this paper, five particulate emission points from a sinter plant in China, including anthracite crusher, raw material blender, sinter strand, screener, and circular cooler, were selected for particle sampling. The particle size distribution, the toxic element content (As, Cd, Co, Cr, Cu, Ni, Pb, Ti, and Zn), and the morphology of the samples were determined by the gravimetric method, the ICP-OES, and the SEM-EDS, respectively. In addition, the gray relational analysis method was used to evaluate the rank of the particulate emission points in the sinter plant. The results show that the emission factor of PM, PM, and PM of the whole sintering process is 0.121, 0.075, and 0.039 kg/t-sinter, respectively. Furthermore, the total toxic element emission factor is 5282.49 mg/t-sinter. The sinter strand is the most important emitter and contributes 43.8% of PM, 53.3% of PM, 56.4% of PM, and 81.1% of total toxic element in the sinter plant. Nevertheless, particles emitted from the post-sintering process are non-negligible and contribute 48.8% of PM, 41.3% of PM, 38.5% of PM, and 15.5% of total toxic element in the sinter plant. [ABSTRACT FROM AUTHOR]

In this study the on-road particle number (PN) performance of a Euro-5 direct-injection (DI) gasoline passenger car was investigated. PN emissions were measured using the prototype of a portable emission measurement system (PEMS). PN PEMS correlations with chassis dynamometer tests show a good agreement with a chassis dynamometer set-up down to emissions in the range of 1·10 10 #/km. Parallel on-line soot measurements by a photo acoustic soot sensor (PASS) were applied as independent measurement technique and indicate a good on-road performance for the PN-PEMS. PN-to-soot ratios were 1.3·10 12 #/mg, which was comparable for both test cell and on-road measurements. During on-road trips different driving styles as well as different road types were investigated. Comparisons to the world harmonized light-duty test cycle (WLTC) 5.3 and to European field operational test (euroFOT) data indicate the PEMS trips to be representative for normal driving. Driving situations in varying traffic seem to be a major contributor to a high test-to-test variability of PN emissions. However, there is a trend to increasing PN emissions with more severe driving styles. A cold start effect is clearly visible for PN, especially at low ambient temperatures down to 8 °C. [ABSTRACT FROM AUTHOR]

Globally more than a quarter of the total primary energy supply is based on coal combustion. The emissions of coal-fired power plants (CFPPs) are regulated in many industrialized countries and therefore power plants use cleaning techniques to minimize emissions such as sulfur dioxide (SO2) and particles. In this study, the particulate emissions from coal combustion were investigated at a CFPP (506MW) used for combined heat and power production in Helsinki, Finland. Fine particle samples (PM1) were collected after electrostatic precipitator before the desulfurization plant (DSP), including flue gas desulfurization unit (FGD) and baghouse filters, and simultaneously in the smokestack to study the influence of DSP to particulate mass and chemistry. The DSP removed over 97% of particle mass in flue gas. Trace metals were removed efficiently but contribution of some ionic compounds increased in the FGD process. The particle properties were studied in more detail in the smokestack including particle size distribution measurements and size-segregating sampling to study chemical composition and morphology of particles. The particulate emissions from the CFPP were relatively small, consisting mainly of products and reagents of the FGD process (e.g., CaSO4, NaCl) and partly of the primary emissions from the coal combustion (e.g., mineral ash and reaction products of gas phase components). The maximum in particle volume was detected at 0.68µm. PM1 contributed on average 62 ± 5% to PM10 mass. Besides particulate matter, also the gas-phase emission of mercury was studied because coal combustion is one of the major sources of mercury found in the environment. The mercury emissions were within the proposed limits in the EU. [ABSTRACT FROM AUTHOR]

Highlights: [•] Promising Croton megalocarpus oil preheated and directly applied on engine. [•] A direct plant oil firing micro trigeneration developed for domestic sector. [•] Study the particulate emission of the engine with direct plant oil firing. [•] Reveal the fundamental reasons for the performance and emission variation. [ABSTRACT FROM AUTHOR]

Abstract: A Life Cycle Inventory (LCI) was developed to identify the unit processes in the life-cycle of biogas production and utilization offering the greatest opportunities for emission to air reduction, hence potential for environmental improvement. The systems investigated included single feedstock digestion and multiple feedstock co-digestion, small (<500kWel) and large-scale (≥500kWel) biogas plants, and selected biogas utilization pathways and digestate management options. Analysis was performed in accordance with ISO 14040 and 14044 standards, using SimaPro 7.2 software and Ecoinvent® v2.1 database. The analysis is based on published data considering primarily conditions for Germany. Results indicated significant variation of emission levels for all unit processes related to biogas production and utilization. Emissions from the feedstock supply logistics were highly influenced by the origin of feedstock used. For example, the fossil fuel related carbon dioxide (CO2,fossil) emissions associated with feedstock supply were over 50 times higher for Municipal Solid Waste (MSW) compared to cattle manure. The higher value for MSW was associated with the requisite collection, transport and pre-treatment, whereas only transportation was required for cattle manure. Emissions from unit processes in biogas plant operation and biogas utilization depended on combined efficiency of energy generation (electricity and thermal), potential substitution of fossil fuels with biogas and utilization of the heat by-product of electricity generation. For example, the results indicated that upgrading of biogas to biomethane, with almost 100% conversion efficiency, caused 6 times less non-methane volatile organic compounds (NMVOC) emissions if plant heating was supplied from coupled small-scale CHP unit as opposed to heating with natural gas. Harnessing of the residual biogas from digestate storage areas was estimated to reduce methane emission by a factor up to 14. Overall, this study provides basic data required for identification and mitigation of emission ‘hot-spots’ in biogas production and utilization, including the evaluation of environmental and public health impacts of biogas technology options by attributional Life Cycle Assessment (LCA) methodology. [Copyright &y& Elsevier]

• Injectors were fouled for continuous 55 h using market fuel without detergent. • Pulse width, flow loss and SEM images were used to identify injector coking status. • Effects of injector deposits on engine combustion and emissions were investigated. • Indicated thermal efficiency improved by up to 0.44% after removing tip deposits. • Particulate emissions were reduced by up to 45% when tip deposits were removed. Gasoline direct injection (GDI) engine development is facing the great challenges in both fuel economy and particulate emissions. Trade-off is often required in GDI engines to sacrifice fuel economy in order to meet the strict emission regulations. GDI injector deposits have been identified as a potential cause of increased particulate emissions. In this work, a series of experimental tests was conducted on a 1.5 L turbocharged GDI engine to further understand the effect of injector deposits. The deposits formed on the injector tip surface were removed after the 55-hour fouling test and their effects on fuel consumption, in-cylinder combustion, thermal efficiency and engine out emissions were investigated before and after the removal. The spray characteristics of an identical injector under clean and fouled conditions were examined and the deposits inside the injector nozzle holes were observed by a scanning electron microscope. The test injectors were mildly fouled with an average of 1.5% flow rate loss and 1.84% injection pulse width increase. After removing the injector tip surface deposits, the engine combustion phase became advanced and the peak in-cylinder pressure increased. The combustion efficiency was close to 98% and showed no significant change. Although the indicated thermal efficiency was only slightly improved by 0.31–0.44% after removing the tip surface deposits, the particulate emissions were significantly affected and reduced by up to around 45%. At the meantime, NOx emissions moderately increased by approximately 12% after removal and no significant change occurred in the THC and CO emissions. [ABSTRACT FROM AUTHOR]