Particle Mass Emissions Research Articles

Comprehensive analysis of particle emissions from miniature turbojet engine

Emission of particulate matter from jet engines contribute to deterioration of air quality in the vicinty of the airports and to formation of contrails in higher layers of the atmosphere. This article presents the results of the measurements of particle emissions from a miniature jet engine GTM-120 fueled conventional aviation fuel Jet A-1. Analysis of particle size distribution, number, mass and volume emission indexes has been made, as well as the analysis of the emission intenisty and mass emission rate. Obtained results were related to LTO cycle phases. The results shows, that the particle number concentration was the lowest for low engine loads, with characteristic diameter of 69.8 nm and the particles concentration of 7.7 x 106 particles/cm3. For thrust increase, the characteristic diameter is smaller, and the particles distribution is no longer single-mode. The highest particles concentration for cm3 is for 100% thrust and is equal to 1.55 x 107 particles, with characteristic diameter of 34 nm.

Optimising the Particulate Emission Characteristics of a Dual-Fuel Spark Ignition Engine by Changing the Gasoline Direct Injection Strategy

In the current global scenario, it is essential to find more effective and practical solutions to mitigate the problem of particulate emissions from vehicles. In this research, particulate emission characteristics with changing GDI pressure or applying a split GDI strategy with different second injection timings were initially explored in a Dual-Fuel Spark Ignition (DFSI) engine, which employs Ethanol Port Injection (EPI) plus Gasoline Direct Injection (GDI). The experimental results show that by increasing GDI pressure (PGDI) from 5.5 MPa to 18 MPa, ignition delay (θF) shows a small decrease of 0.68 degrees. The parameters, such as maximum in-cylinder temperature (TMI) and exhaust gas temperature (TEG), each increase by 53.75 K and 13.84 K. An apparent reduction of 59.5% and 36.26% was achieved for the concentrations of particulate number (NP) and particulate mass (MP), respectively. Particulate emissions are effectively reduced by a split GDI strategy with an appropriate range of second injection timing (tGDI2). Under tGDI2 = −260 ºCA, NP and MP concentrations exhibit a relatively lower level. However, by delaying tGDI2 from −260 ºCA to −140 ºCA, there is an increase of more than 60% in NP concentration. The research findings help offer new and valuable insights into optimising particulate number and mass emissions from DFSI engines. Moreover, the findings could contribute novel and valuable insights into the optimisation of particulate emission characteristics in DFSI engines.

A novel valve strategy for particulate matter reduction in a gasoline direct injection engine operated at cold conditions

In this study, we proposed a novel intake strategy to reduce Particulate matter (PM) emissions from gasoline direct-injection (GDI) engines during cold-start conditions emissions. This strategy is characterized by generating strong intake turbulence and low in-cylinder pressure during fuel injection through delayed intake valve opening, which theoretically promotes fuel atomization and fuel-air mixture, thereby suppressing PM formation during combustion. Experiments were conducted on a single-cylinder GDI research engine, operating at 1500 rpm, 3, 6, and 8 bar IMEP, and stoichiometric air-fuel ratio conditions with low coolant and lubricant temperatures to experimentally demonstrate the effectiveness of the proposed valve strategy in reducing PM emissions. Benchmark tests were performed using an intake camshaft with intake valve opening (IVO) at −13 °aTDC and intake valve closing (IVC) at 227 °aTDC. The novel strategy uses an intake camshaft with very late IVO at 66 °aTDC and IVC at 226 °aTDC. Two injection pressures (Pinj = 100/200 bar) were used to evaluate the pressure requirement for achieving low PM emissions with both strategies. Start of injection was swept and optimized to match the valve strategy. The results showed that the novel valve strategy leads to a 50%–90% reduction in particle number and mass emissions in cold-start conditions, and a lower injection pressure requirement to achieve comparable particle number and mass emissions compared with the normal one. For the novel valve strategy, the fuel impingement with early injection timings is largely mitigated, and thus an early injection timing shortly before the IVO is recommended.

Online characterization of primary and secondary emissions of particulate matter and acidic molecules from a modern fleet of city buses

Abstract. The potential impact of transitioning from conventional fossil fuel to a non-fossil-fuel vehicle fleet was investigated by measuring primary emissions via extractive sampling of bus plumes and assessing secondary mass formation using the Gothenburg Potential Aerosol Mass (Go:PAM) reactor from 76 in-use transit buses. Online chemical characterization of gaseous and particulate emissions from these buses was conducted using chemical ionization mass spectrometry (CIMS) with acetate as the reagent ion, coupled with the Filter Inlet for Gases and AEROsols (FIGAERO). Acetate reagent ion chemistry selectively ionizes acidic compounds, including organic and inorganic acids, as well as nitrated and sulfated organics. A significant reduction (48 %–98 %) in fresh particle emissions was observed in buses utilizing compressed natural gas (CNG), biodiesels like rapeseed methyl ester (RME) and hydrotreated vegetable oil (HVO), and hybrid-electric HVO (HVOHEV) compared to diesel (DSL). However, secondary particle formation from photooxidation of emissions was substantial across all the fuel types. The median ratio of particle mass emission factors of aged to fresh emissions increased in the following order: DSL buses at 4.0, HVO buses at 6.7, HVOHEV buses at 10.5, RME buses at 10.8, and CNG buses at 84. Of the compounds that can be identified by CIMS, fresh gaseous emissions from all Euro V/EEV (Enhanced Environmentally friendly Vehicle) buses, regardless of fuel type, were dominated by nitrogen-containing compounds such as nitrous acid (HONO), nitric acid (HNO3), and isocyanic acid (HNCO), alongside small monoacids (C1−C3). Notably, the emission of nitrogen-containing compounds was lower in Euro VI buses equipped with more advanced emission control technologies. Secondary gaseous organic acids correlated strongly with gaseous HNO3 signals (R2=0.85–0.99) in Go:PAM, but their moderate to weak correlations with post-photooxidation secondary particle mass suggest that they are not reliable tracers of secondary organic aerosol formation from bus exhaust. Our study highlights that non-regulated compounds and secondary pollutant formation, not currently addressed in legislation, are crucial considerations in the evaluation of environmental impacts of future fuel and engine technology shifts.

Sectoral Size‐Resolved Particle Number Emissions With Speciation: Emission Profile‐Based Quantification and a Case Study in the Yangtze River Delta Region, China

AbstractSizes and number concentrations are critical parameters for the impact of atmospheric particles on climate and human health. However, comprehensive studies focusing on size‐resolved particle number (PN) emissions from various sectors are scarce. This study aims to fill this research gap by developing sectoral size‐resolved PN emissions for major species including sulfate, organic mass (OM), and black carbon (BC). The size‐resolved emission profiles derived from various measurements in the literature were integrated with a particle mass emission inventory (EI) for 13 major sectors in the Yangtze River Delta region of China as a case study. The particle number size distribution (PNSD) of emitted particles exhibited two distinct peaks: one at approximately 10 nm and the other in the range of 40–60 nm. The primary contributors to PN emissions in the region in 2017 were power plants, gasoline vehicles, diesel vehicles, and cooking sources. In terms of species, OM dominated PN emissions, followed by primary sulfate and then BC. A regional size‐resolved aerosol model employing the size‐resolved PN EI developed here (referred to as the BIN‐SPE experiment) provided reasonably accurate temporal variations of the total PN concentration and captured the PNSD within the size range of 10–300 nm. Uncertainty analysis of sectoral PN emissions across size ranges was carried out and the performance of the BIN‐SPE experiment was compared with those of three commonly used PN emission parameterizations. Our model evaluations highlight future needs for in‐depth investigations into more advanced size‐resolved emissions and secondary OM formation mechanisms.

Effect of alternative fuels on the emissions of a passenger car under real-world driving conditions: a comparison of biodiesel, gas-to-liquid, coal to liquid.

Fossil fuel energy crisis and environmental pollution have initiated the scientific research on alternative fuels. Biodiesel (B100), gas to liquid (G100), and coal to liquid (C100) are superb selections to be substitutes for conventional diesel. To better investigate the emission characteristics of the alternative fuels mentioned above, a portable emission measurement system (PEMS) was used to carry out this study under real-world driving conditions. Results showed that the driving conditions had a notable effect on the vehicle emissions, the CO, THC, and CO2 emissions were higher under urban condition, and the NOx, PM (particle mass), and PN (particle number) emissions were higher under suburban condition. The expressway condition resulted in lower emissions except for PN due to more nucleation particles emitted. The use of B100, G100, and C100 fuels led to a reduction of more than 50% in the CO emission, especially for the C100, but the reduction effects for the THC were not obvious, and among them, G100 is the most prominent. Higher NOx emission was emitted after using the three fuels, especially for the B100; meanwhile, B100 increased the CO2, but G100 and C100 decreased the CO2 emission compared with D100. The PN emissions reduced by 1-2 orders of magnitude in comparison with those from D100 after using the three alternative fuels, and more than 50% of the PM could be reduced. B100 has the most significant particle reduction effect due to its oxygen-containing property, and it produced an evidently higher proportion of nucleation particles than D100, followed by G100 and C100.

Relationship between Exhaled Aerosol and Carbon Dioxide Emission Across Respiratory Activities.

Respiratory particles produced during vocalized and nonvocalized activities such as breathing, speaking, and singing serve as a major route for respiratory pathogen transmission. This work reports concomitant measurements of exhaled carbon dioxide volume (VCO2) and minute ventilation (VE), along with exhaled respiratory particles during breathing, exercising, speaking, and singing. Exhaled CO2 and VE measured across healthy adult participants follow a similar trend to particle number concentration during the nonvocalized exercise activities (breathing at rest, vigorous exercise, and very vigorous exercise). Exhaled CO2 is strongly correlated with mean particle number (r = 0.81) and mass (r = 0.84) emission rates for the nonvocalized exercise activities. However, exhaled CO2 is poorly correlated with mean particle number (r = 0.34) and mass (r = 0.12) emission rates during activities requiring vocalization. These results demonstrate that in most real-world environments vocalization loudness is the main factor controlling respiratory particle emission and exhaled CO2 is a poor surrogate measure for estimating particle emission during vocalization. Although measurements of indoor CO2 concentrations provide valuable information about room ventilation, such measurements are poor indicators of respiratory particle concentrations and may significantly underestimate respiratory particle concentrations and disease transmission risk.

Brake Wear and Airborne Particle Mass Emissions from Passenger Car Brakes in Dynamometer Experiments Based on the Worldwide Harmonized Light-Duty Vehicle Test Procedure Brake Cycle

Brake wear particles, as the major component of non-exhaust particulate matter, are known to have different emissions, depending on the type of brake assembly and the specifications of the vehicle. In this study, brake wear and wear particle mass emissions were measured under realistic vehicle driving and full friction braking conditions using current commercial genuine brake assemblies. Although there were no significant differences in either PM10 or PM2.5 emissions between the different cooling air flow rates, brake wear decreased and ultrafine particle (PM0.12) emissions increased with the increase in the cooling air flow rate. Particle mass measurements were collected on filter media, allowing chemical composition analysis to identify the source of brake wear particle mass emissions. The iron concentration in the brake wear particles indicated that the main contribution was derived from disc wear. Using a systematic approach that measured brake wear and wear particle emissions, this study was able to characterize correlations with elemental compositions in brake friction materials, adding to our understanding of the mechanical phenomena of brake wear and wear particle emissions.

Characterization of emissions from axle-mounted rail disc brakes

The most important sources for non-exhaust emissions from railways are the contact strip, the contact wire, wheels, rails and brakes. It is expected that the major share of PM (particulate matter) emission can be assigned to the brakes. In order to quantify the emissions from railway brakes, a series of test bench tests was carried out. These tests aimed at a quantification and characterization of emissions for both sintered and organic brake pads. The measurement setup included monitoring of emitted particle mass and particle number (PN) in the size range from 10 nm to 32 µm. PM10 emission factors could be derived in the range from 0.11 g/km to 4.21 g/km. Emissions from organic brake pads were higher compared to those from sintered materials. The monitoring of particle number concentration showed a significant dependency of PN emissions from the surface temperatures as soon as a critical temperature was exceeded.

Particulate matter emissions from light-duty gasoline vehicles under different ambient temperatures: Physical properties and chemical compositions

Fine particulate matter (PM2.5) from vehicle exhaust is typically emitted at breathing height and thus imposes severe adverse effects on human health and air quality. However, there is currently limited knowledge on the characteristics of PM2.5 in exhaust, specifically its chemical components, at different ambient temperatures. Particulate emissions from typical light-duty gasoline vehicles (LDGVs) were investigated on a chassis dynamometer according to the Worldwide Harmonized Light-Duty Test Cycle at ambient temperatures of 38 °C, 28 °C, 15 °C, 5 °C and − 7 °C. The results showed a significant increase in particulate mass (PM) and particle number (PN) emissions with decreasing ambient temperature, particularly during cold starts below 5 °C. The particle size distributions exhibited distinct bimodal patterns, with accumulation-mode (AM) particles (60–125 nm) dominating the gasoline direct injection (GDI) distribution and nucleation-mode (NM) particles (8–12 nm) dominating the port fuel injection (PFI) distribution. AM particles were more temperature-sensitive than NM particles. Lower temperatures produced higher emissions of elements, carbonaceous components, and large-ring polycyclic aromatic hydrocarbons, while water-soluble ions showed an opposite trend. The total toxic equivalent, primarily influenced by benzo[a]pyrene, was significantly higher at −7 °C. The penalty distribution of LDGV PM and PN, defined by comparing the emissions at the various temperatures to those at regulated temperatures (23–30 °C), exhibited notable temporal heterogeneity (winter > autumn > spring > summer) and spatial heterogeneity (northern China > southern China). These findings are essential for establishing more stringent vehicle emission standards and improving emission models in cold environments.

Marine Fuel Regulations and Engine Emissions: Impacts on Physicochemical Properties, Cloud Activity and Emission Factors

AbstractMarine regulations aim to reduce sulfur and nitrogen exhaust emissions from maritime shipping. Here, two compliance pathways for reducing sulfur dioxide emissions, fuel sulfur content reduction and exhaust wet scrubbing, are studied for their effects on physicochemical properties and cloud forming abilities of engine exhaust particles. A test‐bed diesel engine was utilized to study fresh exhaust emissions from combustion of non‐compliant, high sulfur content fuel with (WS) and without (HiS) the usage of a wet scrubber as well as a regulatory compliant, low sulfur content fuel (LoS). Particle number emissions are decreased by ≈99% when switching to LoS due to absence of 20–30 nm sulfate rich particles. While number emissions for WS are also decreased, a shift in the sulfate mode toward larger sizes was found to increase particle mass emission factors by at least 31%. Changes in the mixing state induced by the compliance measures are reflected in the hygroscopicity of the exhaust particles. Fuel sulfur reduction decreased cloud condensation nuclei emissions by at least 97% due to emissions of primarily hydrophobic soot particles. Wet scrubbing increased those emissions, mainly driven by changes in particle size distributions. Our results indicate that both compliance alternatives have no obvious impact on the ice forming abilities of 200 nm exhaust particles. These detailed results are relevant for atmospheric processes and might be useful input parameters for cloud‐resolving models to investigate ship aerosol‐cloud interactions and to quantify the impact of shipping on radiative budgets from local to global scales.

Effects of Diesel Emissions on Black Carbon and Particle Number Concentrations in the Eastern U.S.

The effects of emissions of diesel engines on black carbon and particle number concentrations, as well as climate-relevant aerosol properties, are explored for a summertime period in the Eastern U.S. using the chemical transport model PMCAMx-UF. A 50% reduction in diesel particulate emissions results in lower (23%) black carbon mass concentrations, as expected, and similar changes both in magnitude (27–30%) and spatial pattern for the absorption coefficient. However, an average 2% increase in the total particle number concentrations is predicted due to a decrease in the coagulation and condensation sinks and, at the same time, a 2% decrease in N100 (particles larger than 100 nm) concentrations. The diesel reduction results suggest that mitigation of large diesel particles and/or particle mass emissions can reduce climate-relevant properties related to the absorption of black carbon and provide health benefits; however, the changes could also have the unintended effect of increased ultrafine particle number concentrations. Changes in cloud condensation nuclei are predicted to be significantly less than expected, assuming a proportional reduction during this photochemically active period. Doubling the diesel emissions results in a domain-averaged 3% decrease in total particle number concentrations and a 3% increase in N100 concentrations. PM2.5 BC concentrations increase on average by 46%, and similar changes (52–60%) are predicted for the absorption coefficient. Extinction coefficients for both perturbation simulations changed by only a few percent due to the dominance of scattering aerosols in the Eastern U.S. during this period characterized by high photochemical activity.

Iron Oxide and Hydroxide Speciation in Emissions of Brake Wear Particles from Different Friction Materials Using an X-ray Absorption Fine Structure

Iron (Fe), the main component of non-exhaust particulates, is known to have variable health effects that depend on the chemical species of iron. This study characterized the possible contribution of iron oxides and hydroxides to airborne brake wear particles under realistic vehicle driving and braking conditions with different brake pad friction materials. We found significant differences in wear factors and PM10 and PM2.5 emissions between non-asbestos organic (NAO) and European performance (ECE) brake pads. Iron was the dominant contributor to PM10 and PM2.5 brake wear particles for both NAO and ECE. The iron concentration ratio in the particle mass (PM) was comparable to the disc-to-pads ratio measured by wear mass. The fact that magnetite, which is of interest with respect to health effects, was less abundant in NAO than in ECE suggested that tribo-oxidations occurred in NAO. Metallic iron is generated not only from abrasive wear but also from tribo-chemical reduction with magnetite as the starting material. We found that there were differences in PM emissions between brake friction materials, and that the phase transformations of iron differed between friction materials. These differences were apparent in the distribution of iron oxides and hydroxides. Heat, tribo-oxidation, and tribo-reduction are intricately involved in these reactions.

Characterization of in-cylinder spatiotemporal flame and solid particle emissions for ethanol-gasoline blended in gasoline direct injection engines

Stricter regulations for internal combustion engines have necessitated the inclusion of eco-friendly fuels with conventional ones to reduce gas and solid emissions. Gasoline direct injection (GDI) engines, however, have been found to produce more particle number and mass emissions than port fuel injection engines. To address this, bioethanol fuel has been selected as an additive eco-friendly fuel for gasoline, with the aim of reducing particle emissions. In this study, we quantitatively characterize in-cylinder spatiotemporal flame to feature combustion performance and particle emissions for ethanol fuel in the GDI combustion chamber. We examined three engine combustion modes differed in equivalence ratio and injection strategy to produce various combustion results to quantify combustion performance and particle emission characteristics. Using an eight-channel non-intrusive flame luminosity sensor in one cylinder, we measured the flame front and its propagation direction. At the tailpipe, we measured particulate emissions using an engine exhaust particle sizer and a micro soot sensor coupled with a catalytic stripper that removed semi-volatile compounds. Our study found that increasing ethanol fuel content for different combustion modes resulted in distinct combustion and flame development. The particle size distribution also showed different patterns at each combustion mode, depending on the ethanol content. Lean combustion modes yielded high diffusion flame intensity compared to stoichiometric combustion mode, which resulted in a larger amount of particle formation. The physical properties of ethanol fuel were found to predominantly determine the fuel-air mixture quality, combustion process, and flame development at each combustion mode. An increase in ethanol fuel content at lean-homogeneous mode resulted in higher diffusion flame intensity and larger particle emissions. Our comparative study of flame and solid particles for ethanol fuel content improves the understanding of in-cylinder combustion processes and their correlations.

Determination of exhaust emission characteristics in the RDE test using the Monte Carlo method

The article presents a method of determining the characteristics of exhaust emissions and fuel mass consumption in real driving conditions based on a single test using the Monte Carlo method. The exhaust emission characteristics used are the relations between the emissions and the average vehicle speed, and the characteristic of the fuel mass consumption is the dependence of the fuel mass consumption at the average vehicle speed. The results of empirical research of a passenger car with a spark-ignition engine in the RDE test were used. The use of the Monte Carlo method made it possible to select the initial and final moments of averaging the process values, thanks to which it was possible to determine the discrete values of the characteristics for various values of average vehicle speeds. The determined discrete characteristics of the particulate mass and number emissions and fuel mass consumption relative to the average vehicle speed were approximated by polynomial functions of the second and third degree. The determined discrete characteristics, presented as sets of points, were characterized by a relatively small dis-persion in relation to their polynomial approximations. The average relative deviation of the points of discrete characteristics from the value of the polynomial was in most cases small less than 4%, only in the case of the number of particles emitted deviated from this, as the average relative deviation of the measured points from the determined polynomial was nearly 14%. Combined with the results of RDE empirical studies, the Monte Carlo method proved to be an effective method for determining the characteristics of exhaust emissions, measured in real vehicle operating conditions. The main advantage of the proposed method was a significant reduction in the actual workload necessary to carry out the empirical research where it became possible to determine the charac-teristics in a large range of vehicle average speed values with just one drive test. Using standard methods of meas-uring this type of data, it would be necessary to conduct multiple tests, driving at different average vehicle speeds.

Comparison of the time-dependent characteristics between particle mass and particle number emissions during oil heating and emission mitigation strategies

It is important to understand the cooking particles emitted over time to mitigate cooking pollution, but current control strategies fail to consider both particle mass and number emissions. Therefore, this study was designed to compare the differences in time-dependent characteristics of particle mass and number emissions and to propose comprehensive mitigation strategies that consider both characteristics. For this purpose, the effects of various factors on both emissions were analyzed, and time-dependent emission rate models were developed. The time-dependent models obtained were statistically significant (P < 0.001), with most R2 values greater than 0.90. The masses and numbers of particles emitted often varied in the opposite direction. During the smoking stage, corn oil exhibited low particle mass emissions while its particle number emission rate (TERn) reached 109#/s. However, at higher temperatures (T > TDM), the percentage difference in TERn with increasing oil volume decreased from 7.1% to 3.5%, while that in PM2.5 emission rate with decreasing oil volume was almost more than 25%. This indicated that the increased oil volumes were more effective in reducing the particle masses emitted from corn oil than in increasing the numbers of particles emitted, and similar conclusions were also drawn for decreasing oil surface area. Overall, oils exhibiting lower particle mass emissions and lower cooking temperatures were recommended for cooking. Lower oil volumes and larger pans should be used at relatively lower temperatures (T < TDM) primarily to mitigate particle number emissions, while higher oil volumes and smaller pans should be used at higher temperatures to control particle mass emissions.

Hydrogenated terpenic renewable fuels: Emissions and combustion analysis

Waste terpenes from paper industry, pine resin tapping or citric industry are abundant feedstocks that can be used as components in diesel blends. However, terpenes such as turpentine or orange oil are highly reactive, tend to form deposits and show high sooting tendency. These drawbacks can be solved with hydrogenation, which reduces the degree of unsaturation of the molecule and thus, the formation of soot. In this work, blends at 20 vol % of hydrogenated turpentine and hydrogenated orange oil in diesel fuel were tested in a Euro 6 diesel engine following Worldwide harmonized Light-duty Test Cycle (WLTC). Engine performance, gaseous and particle matter emissions and combustion analysis from these blends were compared with those from diesel fuel. Engine performance was similar for all fuels, with slight differences in equivalence ratio and exhaust gas recirculation (EGR) rate. CO and HC emissions were increased whereas NOx emissions remained constant when blends were tested, with respect to diesel. Sooting tendency was improved since particle mass emissions were reduced despite the particle number emissions were similar to those from diesel. Combustion was quite similar between all fuels and only ignition delay was longer and combustion velocity higher for blends in comparison with diesel.

Interlaboratory Study on Brake Particle Emissions Part II: Particle Number Emissions

The Particle Measurement Programme (PMP) informal working group co-ordinated a global interlaboratory study (ILS) on brake wear particle emissions with the participation of 16 laboratories in 2021. Two articles present the results of the ILS: (I) particulate matter mass (PM) and (II) particle number (PN) emissions. The test matrix covered different brake systems, including ECE and NAO pad materials with grey cast iron discs and a drum brake. Regarding PN, the study measured the total particle number from approximately 10 nm to 2.5 µm (TPN). Some testing facilities measured solid particle number emissions (SPN) in parallel. The mean TPN concentrations ranged from 9.1 × 108 #/km/brake to 1.1 × 1010 #/km/brake. TPN and SPN emission levels were comparable, except for one lab that measured very high volatile particle emissions for one brake system. The minimum and maximum SPN emissions for a given brake differed by a factor of 2.5 ± 0.5, comparable to data from exhaust SPN ILS measurements. This article provides an overview of lessons learned and subsequent measures incorporated in an upcoming global technical regulation to reduce measurement variability when sampling and measuring brake particle emissions for light-duty vehicles up to 3.5 t.

Temperature-dependent particle mass emission rate during heating of edible oils and their regression models

Particulate matter emitted by heated cooking oil is hazardous to human health. To develop effective mitigation strategies, it is critical to know the amount of the emitted particles. The purpose of this research is to estimate the temperature-dependent particle mass emission rates of edible oils and to develop models for source strength based on the multiple linear regression method. First, this study examined seven commonly used oils by heating experiments. The emission rates of PM2.5 and PM10 were measured, and the effects of parameters such as oil volume and surface area on the emission rates were also analysed. Following that, the starting smoke points (Ts') and aggravating smoke points (Tss') of tested oils were determined. The results showed that oils with lower smoke points had greater emission rates. Notably, the experiments performed observed that peanut, rice, rapeseed and olive oil generated PM2.5 much faster at 240 °C (2.22, 1.50, 0.82 and 0.80 mg/s, respectively, at the highest emission conditions) than that of sunflower, soybean, and corn oil (0.15, 0.12 and 0.11 mg/s, respectively). The temperature, volume, and surface area of oils all had a significant impact on the particle mass emission rate, with oil temperature being the most influential. The regression models obtained were statistically significant (P < 0.001), with the majority of R2 values greater than 0.85. Using sunflower, soybean and corn oils, which have higher smoke points and lower emission rates, and smaller pans for cooking is therefore recommended based on our research findings.

Correction for particle loss in a regulatory aviation nvPM emissions system using measured particle size

To reduce the adverse impact of civil aviation on local air quality and human health, a new international standard for non-volatile Particulate Matter (nvPM) number and mass emissions was recently adopted. A system loss correction method, which accounts for the significant size-dependent particle loss, is also detailed to predict nvPM emissions representative of those at engine exit for emissions inventory purposes. As Particle-Size-Distribution (PSD) measurement is currently not prescribed, the existing loss correction method uses the nvPM number and mass measurements along with several assumptions to predict a PSD, resulting in significant uncertainty.Three new system loss correction methodologies using measured PSD were developed and compared with the existing regulatory method using certification-like nvPM data reported by the Swiss and European nvPM reference systems for thirty-two civil turbofan engines representative of the current fleet. Additionally, the PSD statistics of three sizing instruments typically used in these systems (SMPS, DMS500 and EEPS) were compared on a generic aero-engine combustor rig.General agreement between the three new PSD loss correction methods was observed, with both nvPM number- and mass-based system loss correction factors (kSL_num and kSL_mass) within ±10% reported across the engines tested. By comparison, the existing regulatory method was seen to underpredict kSL_num by up to 67% and overpredict kSL_mass by up to 49% when compared with the measured-PSD-based methods, typically driven by low nvPM mass concentrations and small particle size. In terms of the particle sizing instrument inter-comparison, an agreement of ±2 nm for the GMD and ±0.08 for the GSD was observed across a range of particle sizes on the combustor rig. However, it was seen that these differences can result in a 19% bias for kSL_num and 8% for kSL_mass for the measured-PSD-based methods, highlighting the need for further work towards the standardisation of PSD measurement for regulatory purposes.