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Sustainable aviation fuels (SAFs) have different compositions compared to conventional petroleum jet fuels, particularly in terms of fuel sulfur and hydrocarbon content. These differences may change the amount and physicochemical properties of volatile and non-volatile particulate matter (nvPM) emitted by aircraft engines. In this study, we evaluate whether comparable nvPM measurement techniques respond similarly to nvPM produced by three blends of SAFs compared to three conventional fuels. Multiple SAF blends and conventional (Jet A-1) jet fuels were combusted in a V2527-A5 engine, while an additional conventional fuel (JP-8) was combusted in a CFM56-2C1 engine. We evaluated nvPM mass concentration measured by three real-time measurement techniques: photoacoustic spectroscopy, laser-induced incandescence, and the extinction-minus-scattering technique. Various commercial instruments were tested, including three laser-induced incandescence (LII) 300s, one photoacoustic extinctiometer (PAX), one micro soot sensor (MSS+), and two cavity-attenuated phase shift PM SSA (CAPS PM SSA) instruments. Mass-based emission indices (EI m) reported by these techniques were similar, falling within 30 % of their geometric mean for EI m above 100 mg per kg fuel (approximately 10 µ g PM m -3 at the instrument); this geometric mean was therefore used as a reference value. Additionally, two integrative measurement techniques were evaluated: filter photometry and particle size distribution (PSD) integration. The commercial instruments used were one tricolor absorption photometer (TAP), one particle soot absorption photometer (PSAP), and two scanning mobility particle sizers (SMPSs). The TAP and PSAP were operated at 5 % and 10 % of their nominal flow rates, respectively, to extend the life of their filters. These techniques are used in specific applications, such as on board research aircraft to determine particulate matter (PM) emissions at cruise. EI m reported by the alternative techniques fell within approximately 50 % of the mean aerosol-phase EI m. In addition, we measured PM-number-based emission indices using PSDs and condensation particle counters (CPCs). The commercial instruments used included TSI SMPSs, a Cambustion differential mobility spectrometer (DMS500), and an AVL particle counter (APC), and the data also fell within approximately 50 % of their geometric mean. The number-based emission indices were highly sensitive to the accuracy of the sampling-line penetration functions applied as corrections. In contrast, the EI m data were less sensitive to those corrections since a smaller volume fraction fell within the size range where corrections were substantial. A separate, dedicated experiment also showed that the operating laser fluence used in the LII 300 laser-induced incandescence instrument for aircraft-engine nvPM measurement is adequate for a range of SAF blends investigated in this study. Overall, we conclude that all tested instruments are suitable for the measurement of nvPM emissions from the combustion of SAF blends in aircraft engines. [ABSTRACT FROM AUTHOR]

The U.S. Environmental Protection Agency (US EPA) requires residential wood heaters (RWHs) to meet particulate matter (PM) emission limits in order to lower ambient concentrations and reduce public exposure. The current US EPA dilution tunnel PM measurement methods for RWHs were developed several decades ago and use manual filter samples to generate a single PM value for tests that can last more than 12 hours for stoves and 30 hours for central heating appliances. This approach results in averaging periods of high and low emissions together and provides limited data on emissions over the entire burn profile. Over the last decade, the U.S. ambient fine particulate monitoring network has transitioned to the routine use of online automated methods. However, stationary source measurement methods have not made this transition. There are no substantial technical issues in implementing real-time automated methods to measure PM for RWH emission certification purposes. The Thermo Scientific Tapered Element Oscillating Microbalance (TEOM™) has been widely used for ambient PM measurements. It is a true inertial mass measurement with high time resolution and sensitivity. This work compares measurements obtained using a Thermo 1400 or 1405 TEOM with ASTM E2515 manual filter samples, the current US EPA Federal Reference Method, for 172 test runs across a wide range of stoves and PM loading conditions. The TEOM measurements used the same filter media, similar filter face velocities, and filter temperatures as manual methods. PM measurements were well correlated (R2 > 0.9), with TEOM values typically lower by 5% to 10%. TEOM data capture was high, with filter changes resulting in ~5 minutes of lost data, usually once or twice during a multi-hour test. We discuss differences between the two methods, such as post-sampling equilibration and measurement of PM on sample train surfaces (probe "catch"). We also provide examples of substantial non-water semi-volatile mass loss during sampling. Implications: Measurement methods for continuous PM and our understanding of their performance has dramatically improved over the last thirty years. Highly time-resolved measurements of PM from residential wood heating appliances in an appliance certification testing context provide additional insight into both appliance performance and the suitability of the test method to assess that performance. This continuous measurement approach offers new opportunities to replace traditional US regulatory PM sampling integrated manual source methods like ASTM E2515 or EPA Method 5G testing. For measurement of combustion products that can have a wide range of physical and chemical characteristics, the TEOM's actual mass measurement principle has advantages over the sensitivity of surrogate methods to different aerosols for use in a regulatory program. Although the TEOM is commonly used to measure ambient PM, it can readily be configured to meet the needs of continuous emission testing. [ABSTRACT FROM AUTHOR]

Particulate matter (PM) generated by residential wood combustion is a major environmental concern in Europe. This study focuses on the influence of potassium chloride (KCl) on fine particle emissions from a modern wood stove. Wood logs with and without KCl impregnation were subjected to batch combustion and emission measurements. A bi-modal particle number-size distribution characterized by a nucleation mode and an accumulation mode was identified for all types of wood fuel. However, in the presence of KCl, a lower number emission of ultrafine particles and a higher number emission of larger particles (size ∼200–500 nm) were observed. In addition, the emission factor of condensed organic compounds (COC) increased with increasing KCl content, from 0.16 g/kg dry wood for normal wood (NW) to 0.48 g/kg dry wood for wood impregnated with the 2 mol/L KCl solution (HKW), most likely due to the facilitated heterogeneous condensation of semi-volatile hydrocarbons on pre-existing ash particles. In addition, the emission factor of soot particles also increased slightly when the KCl content was high, from 1.47 g/kg dry wood for NW to 2.23 g/kg dry wood for HKW. • PM emissions from the combustion of KCl-impregnated wood in a domestic stove were characterized. • The emission of accumulation mode particles from the wood stove increased in the presence of KCl. • The organic carbonaceous emissions from the wood stove increased with increasing KCl content in the fuel. • A high KCl content in the fuel slightly promoted the soot emissions from the wood stove. [ABSTRACT FROM AUTHOR]

Particulate matter in the atmosphere is known to affect Earth's climate and to be harmful to human health. Accurately measuring particles from emission sources is important, as the results are used to inform policies and climate models. This study compares the results of two ELPI + devices, two PM10 cascade impactors and an eFilter, in combustion emission measurements. The comparison of the instruments in a realistic setting shows what types of challenges arise from measuring an emission aerosol with unknown particle morphologies and densities, different particle concentrations and high temperature. Our results show that the PM10 cascade impactors have very good intercorrelation when the collected mass is greater than 150 µg, but below that, the uncertainty of the results increases with decreasing mass. The raw signals of two ELPI + devices were nearly identical in most samples, as well as the particle number concentrations and size distributions calculated from raw signals; however, transforming the current distributions into mass distributions showed variation in the mass concentration of particles larger than 1 µm. The real-time time signal measured by eFilter was similar to the total current measured by ELPI+. The eFilter and PM10 cascade impactors showed similar particle mass concentrations, whereas ELPI + showed clearly higher ones in most cases. We concluded that the difference is at least partially due to volatile components being measured by ELPI+, but not by the mass collection measurements. Copyright © 2019 American Association for Aerosol Research [ABSTRACT FROM AUTHOR]

In this paper, an experimental study was carried out to assess the effects of diesel/ethanol blends, including pure diesel, diesel (90%)/ethanol (10%) (E10, by mass) and diesel (80%)/ethanol (20%) (E20), on combustion and exhaust particulate matter emissions characteristics in a four-cylinder Diesel engine under a low engine load condition with different injection timings and exhaust gas recirculation ratios. Results indicated that ethanol addition delayed the ignition timing and shortened the combustion duration, meanwhile, produced higher brake thermal efficiency and lower brake specific fuel consumption. Moreover, the total particulate and nucleation mode particle (particle size Dp < 50 nm) number concentrations were increased and the total particulate mass and the accumulation mode (50 nm < Dp < 1000 nm) number concentration were decreased when engine fueled with diesel/ethanol blends compared to pure diesel. [ABSTRACT FROM AUTHOR]

Compared with pure Diesel fuel, Diesel engine fueled with 2,5-dimethylfuran/diesel prolonged the ignition delay, shortened the combustion duration, increased the engine efficiency and decreased the number of accumulation mode particles (50 nm < Dp < 1000 nm), but increased the nucleation mode (Dp < 50 nm) number. The mean diameter of particles was declined with 2,5-dimethylfuran addition due to the increase of small particles number. Ethanol/diesel was more effective in extending the ignition delay, shortening the combustion duration, enhancing the engine efficiency and reducing the number of large size particles, but produced more small size particles compared with 2,5-dimethylfuran/diesel. [ABSTRACT FROM AUTHOR]

A total of 85 PM samples were collected at a site located in a large industrial zone (Porto Marghera, Venice, Italy) during a 1-year-long sampling campaign. Samples were analyzed to determine water-soluble inorganic ions, elemental and organic carbon, and levoglucosan, and results were processed to investigate the seasonal patterns, the relationship between the analyzed species, and the most probable sources by using a set of tools, including (i) conditional probability function (CPF), (ii) conditional bivariate probability function (CBPF), (iii) concentration weighted trajectory (CWT), and (iv) potential source contribution function (PSCF) analyses. Furthermore, the importance of biomass combustions to PM was also estimated. Average PM concentrations ranged between 54 and 16 μg m in the cold and warm period, respectively. The mean value of total ions was 11 μg m (range 1-46 μg m): The most abundant ion was nitrate with a share of 44 % followed by sulfate (29 %), ammonium (14 %), potassium (4 %), and chloride (4 %). Levoglucosan accounted for 1.2 % of the PM mass, and its concentration ranged from few ng m in warm periods to 2.66 μg m during winter. Average concentrations of levoglucosan during the cold period were higher than those found in other European urban sites. This result may indicate a great influence of biomass combustions on particulate matter pollution. Elemental and organic carbon (EC, OC) showed similar behavior, with the highest contributions during cold periods and lower during summer. The ratios between biomass burning indicators (K, Cl, NO , SO , levoglucosan, EC, and OC) were used as proxy for the biomass burning estimation, and the contribution to the OC and PM was also calculated by using the levoglucosan (LG)/OC and LG/PM ratios and was estimated to be 29 and 18 %, respectively. [ABSTRACT FROM AUTHOR]

In this study, Euro V diesel fuel, biodiesel, and methanol-biodiesel blends were tested in a 4-cylinder direct-injection diesel engine to investigate the combustion characteristics and particulate emissions of the diesel engine under five engine loads at the maximum torque engine speed of 1800 rpm. Compared with Euro V diesel fuel, biodiesel gives lower and earlier heat release rate. For the blended fuels, the peak heat release rate becomes higher and retarded. With regard to particulate mass concentration, biodiesel generates less than Euro V diesel fuel, while the blended fuels result in significant reduction especially at high engine loads. Compare with Euro V diesel fuel, the total particle number concentration of using biodiesel is always higher while the geometric mean diameter (GMD) of the particles is lower. With the blended fuel, the total number concentration and GMD decrease in comparison with pure biodiesel. Further analysis shows that the difference between the total number concentration of biodiesel and Euro V diesel fuel is in particles smaller than 50 nm rather than in the larger particles. The use of methanol-biodiesel blends, compared with biodiesel, could reduce the number concentration of all sizes. A comparison between the particulate mass emission and total particulate number concentration with the mass of fuel burned in the diffusion mode show that they are strongly related to each other, even for the blended fuel. [ABSTRACT FROM AUTHOR]

We have used a new high-volume, low-cutoff inertial impactor (HVLI) in a pilot study on chemical characterization and toxicity testing of ambient air PM10in Helsinki, Finland. Ambient airPM10was collected at 1100 L/min in 2- to 4-day periods. Two different PM10samples were selected to represent wintertime combustion type and springtime resuspension type particulate matter (PM) pollution. The most abundant water-soluble ions and elements were analyzed by ion chromatography and inductively coupled plasma mass spectrometry, respectively. The proinflammatory activation ¡NO and interleukin 6 (IL-6) production] and viability of cultured murine RAW 264.7 macrophages were tested in 24-h incubations with increasing mass doses (30–2000 µg per 106cells) from the collected PM10samples. The winter sample had a higher assessed PM2.5fraction and sulfate content, and lower chloride, sodium, calcium, aluminum, copper, manganese, and especially iron contents than the spring sample. Both PMjo samples induced dose-dependent NO production in murine macrophages, and the springtime PM10produced also a strong, dose-dependent IL-6 production. In conclusion, the HVLI proved to be a suitable technique for short-term collection of relatively large ambient air PM masses, enabling extensive chemical characterization and toxicity testing from the same samples. [ABSTRACT FROM PUBLISHER]

This paper systematically reviews the PM sampling and measurement methods, formation mechanisms, distribution, inorganic composition and the factors influencing PM emission during combustion of coal/biomass/MSW. Particle sampling and measurement methods are developing rapidly utilizing various techniques, however, the direct sampling techniques for particle in the high temperature flue gas is still lacking. Particle is generated by a series of physical processes (evaporation, condensation, fragmentation etc.) and chemical reaction processes of inorganic mineral components and organically bound metal compounds in the solid fuels. The available literature data shows that the emission of coarse particles from coal combustion is generally higher than that from biomass, while the emission of ultrafine and fine particle from biomass combustion is higher than that of coal. Particle emission is related to a variety of influencing factors such as solid fuels particle size, inherent ash content, mineral properties, binding form of inorganic elements, combustion parameters (temperature, pressure, residence time, oxygen concentration etc.) and ash chemical composition. The content of Na, K, S, Cl, Si and Al plays a decisive role in PM 10 emissions, the (Na 2 O + K 2 O)/(SiO 2 + Al 2 O 3) ratio of ash can be used as an index to predict the yield of PM 0.3 in coal and biomass combustion. Unlabelled Image • The direct sampling techniques for PM in the high temperature flue gas is lacking. • PM chemical composition generated from coal, biomass and MSW combustion was different. • Ultrafine particles yields follows: Biomass> Coal, Forest biomass> Agricultural biomass. • The (Na 2 O + K 2 O)/(SiO 2 + Al 2 O 3) mass ratio of ash can be used as an index to predict PM 0.3 yields. [ABSTRACT FROM AUTHOR]