Vehicles Exhaust Particulate Matter Emissions: History
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Subjects: Environmental Sciences
Contributor:
Barouch Giechaskiel

In the automotive field the term “particulate matter (PM)” is used for the collected matter on a flow-through filter under specific conditions, and the term “particle” for aerosol particles measured while airborne (suspended matter). Particles are divided into “volatile” and “non-volatile” (or solid) at tailpipe conditions (high temperature, high concentration). Species that at tailpipe conditions appear volatile, may partition toward the particulate phase at atmospheric conditions (low temperature), and the term semi-volatile better characterizes them. The term “semi-volatiles” (instead of “volatiles”) will be used loosely in this text to indicate species not counted after dilution and thermal pre-treatment at 300–400 °C. The term ultrafine particles (i.e., particles < 100 nm) is not so common in the automotive community. Even though the majority of particles has sizes <100 nm, the tail extends to larger sizes. A recent review argued that a better definition for ultrafine particles (focusing on the automotive field) would be particles <500 nm.

  • primary aerosol
  • fresh aerosol
  • secondary aerosol
  • nucleation mode
  • vehicle emissions
  • road transport
  • urban pollution
  • air quality
  • PMP
  • PEMS

1. Introduction

The atmospheric aerosol is a complex and dynamic mixture of solid and liquid particles in the air, generated from natural (such as pollen, sea salt, volcanic ash, and soot particles from natural fires) and anthropogenic sources (e.g., combustion, waste incineration, and road abrasion). Anthropogenic emissions of atmospheric aerosol and its precursors have increased over the past century and are known to have significant impacts on human health [1][2] and climate change [3]. Studies have actually shown that the particulate matter (PM) has a greater impact on health than the gaseous components [4][5]. Globally, >50% of the population lives in urban areas with poor PM air quality [6].
Ambient PM concentrations are monitored in many places around the world, together with several gaseous species. Traffic is an important source of PM and the exhaust emissions of vehicles have been regulated for many years. In the last decade, a solid particle number (SPN) limit has also been imposed in the European Union (EU) legislation [7] and other countries in Asia have followed. There are a few concerns about the representativeness and the usefulness of the SPN limit, as it is today proposed: (i) exhaust and atmospheric particles usually extend to sizes much lower than the cut-point of 23 nm currently included in the regulations; (ii) only solid particles following a thermal treatment are regulated, while atmospheric include additional higher volatility species [8]. Thus, the current standard does not address particles which are representative of real-world exposure to traffic particulate emissions [9][10].

2. PM Emitted from Vehicles

This section will focus on the physical characterization and chemical composition of the PM emitted by vehicles, along with the potential for secondary aerosol formation.

2.1. Primary “Tailpipe” Particles

Figure 1 (left lower corner) plots schematically the exhaust aerosol at the tailpipe and the atmosphere within a few seconds (i.e., primary and delayed primary aerosol) [11][12]. It also shows sampling and measurement (left part), as well as: (i) the resulting PM mass and chemical characterization (lower right part) of a filter [13]; and (ii) particle number size distribution before and after thermal pre-treatment (upper right part) with a solid particle number (SPN) instrument [14].
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Figure 1. Tailpipe “primary” and fresh aged “delayed primary” aerosol consisting of inorganics, organics at the gaseous or particle phase, and soot and ash particles. On the right side the filter based and solid particle number (SPN) counting methods are plotted. Based on [11][12][13][14]. cPOA = condensed primary organic aerosol; IVOC = intermediate volatility organic compound; NVOC = non-volatile organic compounds; PIA = primary inorganic aerosol; POA = primary organic aerosol; PM = particulate matter; SPN = solid particle number; SVOC = semi-volatile organic compound.
At the vehicles’ tailpipe, only primary non-volatile (solid) particles can be found due to the high exhaust gas temperatures, while the majority of precursors are in the gaseous phase (i.e., “semi-volatiles” in this paper). Typically, a soot or accumulation mode is measured at the tailpipe with a mean size >50 nm [15]. Studies of modern gasoline vehicles have found smaller means, around 30 nm [16][17]. The accumulation mode particles consist of many spherules (sometimes called primary particles, a term that will not be used in this text) of elemental carbon [18] with fuel and lubricating oil components [19]. Particle-bound polycyclic aromatic hydrocarbons (PAHs) are also commonly reported [20][21][22][23][24]. A solid core or nano mode with a mean size of 10 nm has also been found [25][26]. This mode consists of amorphous carbonaceous compounds, PAHs, or metallic ash from fuel or lubricant [27][28][29][30][31][32][33]. In one case two separate core modes were found (derived from lubricant and fuel respectively) [34]. Recently, urea non-volatile particles have also been reported at sizes around 20 nm [35][36]. Non-volatile clusters <3 nm have also been reported for compressed natural gas (CNG) engines [37][38]. The modes depend, among others, on the engine, fuel, combustion strategy, and aftertreatment devices [11][39][40][41]. Recently, in addition to the combustion process related solid particles, nanoparticles during braking (motoring) have been reported, even when no fuel injection and combustion process take place in the cylinder [42][43][44]. Engine and aftertreatment wear particles can also been found [45]. The introduction of particulate filters has reduced significantly the concentration of primary particles in the exhaust gas of modern vehicles [7][46]. Sometimes, larger coarse mode particles appear originating from the crankcase ventilation, wear, or soot re-entrainment [47][48]. Regarding the precursor gases, oxidation catalysts reduced hydrocarbons, but in many cases increased the SO2 to SO3 conversion and NH3 [49][50]. NOx reduction aftertreatment decreased NOx [51].

2.2. Delayed Primary “Fresh” Particles

At the tailpipe outlet the aerosol is diluted and cools down [52][53][54]. The precursors (e.g., sulfuric acid, hydrocarbons) [55][56] that were in gaseous phase at the tailpipe (due to the high exhaust gas temperatures) may nucleate to form new nucleation mode particles or condense on other particles (e.g., non-volatile core or accumulation mode). Thus, the “fresh” exhaust aerosol comprises the solid particles in the tailpipe (primary PM) and the newly formed particles during the seconds of mixing of the exhaust gas with ambient air [11][57][58] (Figure 1).
The formed nucleation mode (in the absence of a solid core) peaks at approximately 10 nm depending on the availability of the precursors [47][59][60][61]. Sulfuric acid is the key nucleating compound as measurements [62] and models show [63][64][65][66]. With low sulfur fuels, lubricants play an important role [62][67] and aftertreatment devices enhance the SO2 to SO3 conversion [49]. Relatively high SO2 concentrations can be measured at diesel vehicles compared to gasoline and gas engines due to the higher oxidative environment in the exhaust [68]. Hydrocarbons are then necessary for the subsequent growth of such sulfate core particles [26][69][70]. A nucleation mode can be typically seen with high sulfur fuel (300 ppm) and/or lubricant [62][71], high speeds (exhaust gas temperatures) [49][72], and during regenerations [73][74] (see also discussion in [75]). Without aftertreatment devices, hydrocarbons (alkanes, PAHs) may also form a separate nucleation mode [60]. Without any aftertreatment devices, this nucleation mode has high particle number concentration and large mean size [76], but with aftertreatment devices the concentration and size is usually low [77]. Both fuel and oil are significant sources of hydrocarbons [23][33][78][79][80][81][82][83]. Fuel contributes to volatile organic compounds (VOC) and intermediate volatility organic compounds (IVOC), while oil to semi-volatile organic compounds (SVOC) [84]. More on chemical composition of vehicles exhaust can be found elsewhere [39][85][86][87][88].
At this primary atmospheric dilution stage no significant chemical transformations take place. When looking the complete particle size distribution, the exhaust aerosol formed by different processes is frequently allocated to separate modes with different concentrations and particle size ranges [47]. The size distribution may consist of a cluster mode, one or two core modes, the soot mode and the coarse mode. The formation and properties of each mode (size, chemical composition) depends on the vehicle (engine, aftertreatment, fuel, lubricant) [59][89][90][91][92], driving conditions and the ambient conditions (temperature humidity) [8][93]. Some of the modes may often appear blended and are difficult to distinguish, unless combined with thermal separation techniques, such as treatment with a catalytic stripper or thermodenuder, followed by microscopy.
In terms of mass, under laboratory conditions the soot and ash particles and heavy compounds comprise the solid part (see Figure 1). Primary organic aerosol (POA) and primary inorganic aerosol (PIA) compounds condensed on particles or as a separate nucleation mode consist the condensable PM. It should be mentioned that the compounds that are emitted in the gaseous phase under relevant atmospheric conditions are secondary organic aerosol (SOA) precursors.
Vehicular emissions are eventually diluted by a factor of 1000 or more in the atmosphere [94], but dilution near roads may be lower [95]. A study that summarized measured dilution ratios in function of distance from moving vehicles, reported dilution ratios of 200–500:1 at a distance of 10 m [75][96]. Other researchers provided equations to estimate the dilution ratio [97]. At lower speeds the dilution in the wake of the vehicle can be much higher at the same distance [98][99]. Measurements at different short distances behind moving vehicles (10–50 m) did not find significant evolution of the nucleation mode, after correcting for dilution [96]. In the time scale of a few seconds this nucleation mode seems stable. However, these particles may evaporate after some time in the atmosphere and may subsequently contribute to the formation of secondary aerosol of higher mass [100][101][102]. For example, some studies found that the organic to total carbon ratio is higher for roadside nanoparticles compared to typical exhaust soot particles [103]. On the other hand, other studies found an increase of the particle size from 1.5 m to 15 m from the road [104][105]. Models usually divide the analysis into separate ‘tailpipe to road’ and ‘road to ambient’ parts [6][106]. Most of the changes to particle number concentration and size distribution occur rapidly with the dilution and cooling of the exhaust gas. Later, interaction of fresh particles with relatively aged particles also takes place [107].

2.3. Secondary Particles

In addition to the primary and delayed primary PM, large amounts of secondary particulate matter forms after the exhaust gases are released into the atmosphere [108]. After some hours or days under atmospheric conditions, secondary PM is formed due to oxidation of gaseous precursors. Studies of secondary aerosol formation rate and quantity (yield) are done in smog chambers [109] or oxidation flow reactors [110].
Recent chamber studies have shown that secondary particulate matter from combustion engines consists mainly of organic compounds and ammonium nitrate [111][112][113] and that the secondary PM formation can be significantly larger than primary PM emission [112][114][115][116][117]. Studies that focused on the SOA also found that the contribution of vehicles to SOA can be higher than primary aerosol [112][118][119]. The emissions of secondary PM precursors from internal combustion engines depend on fuel properties [120][44][111][113][121][122][123]. The advantages of the oxidative exhaust aftertreatment and especially the use of diesel particulate filters (DPF) on decreasing aged PM has clearly been shown [124][44][89][122][125][126][127][128]. Catalyzed DPFs on road vehicles were also demonstrated to yield very low SOA over transient operation. Gasoline engines have greater secondary aerosol precursor emissions than diesel engines [124][112][121][125][128][129][130]. However, it was also shown that SOA emissions follow emission standards [116] and recent Euro 6 gasoline vehicles had very low SOA [10]. Gasoline particle filters (GPF) have not shown similar reduction potential against SOA as DPFs [131]. For a natural gas engine, the mass of the aged particles produced by an oxidation flow reactor was hundreds of times higher than the mass of primary particles [91]. Cold start emissions have been shown to have a significant contribution to SOA [10][116][132][133]. These studies highlight the need to better characterize (semi)volatile compounds from vehicles in order to better estimate their contribution to secondary aerosol formation.

2.4. Emission Levels of Solid and Volatile Particles

The introduction of a solid particle number (SPN) limit clearly resulted to a significant decrease of vehicle emissions. For example, DPF vehicles have by a factor of >10,000 lower SPN emissions than vehicles without DPFs (from >1014 #/km to <1010 #/km) [7]. Similarly, SPN emission levels of gasoline direct injection vehicles dropped from >1012 to <1011 #/km [134] with the use of a gasoline particle filter (GPF). In contrast, no SPN emission reductions were observed for vehicle technologies that were not covered by relevant regulations. For example, the SPN emissions of port fuel injection vehicles have remained at the same level (mostly between 1011 and 1012 #/km) for the last 30 years [134]. Mopeds and motorcycles also exhibit high SPN emissions which, depending on engine tuning, can often reach more than 1011 #/km [135]. Any decreases in emission levels of this category were attributed to technology improvements (two-stroke vs. four-stoke, carburetor vs. electronic injection) which were forced by stricter limits in gaseous pollutants [136]. This is an example that demonstrates that satisfactory control of SPN can be achieved by regulating co-pollutants.
One question is how different formation mechanisms of solid and total particle emissions are; this would have an impact on the emission control technologies in each case. In general, SPN control does not necessarily result in a decrease of total particle number (TPN), because the semi-volatile part is formed by ions and organics while the solid part is mostly elemental carbon and ash. In an exaggerated example of the past, a DPF equipped engine was shown to result to higher particle number emissions than the non-DPF one [137]. Later it was shown that due to the low soot concentration post DPF available volatile species preferentially nucleated and formed new particles in the absence of solid cores on where they could condense [138]. Similar findings have been observed in the atmosphere where high particle number levels can be seen when PM is low [139]. A recent study with 130,000 plume measurements found that the number of semi-volatile particles comprised 85% to 94% of total particles [8]. Even though semi-volatile particles can be dominant in terms of number, their contribution to mass depends on the existence or not of a particulate filter. Detailed studies with heavy-duty engines equipped with aftertreatment devices to fulfil the 2007 and 2010 standards (i.e., oxidation catalyst, DPF and selective catalytic reduction (SCR) for NOx) had elemental carbon <20% of total mass [87][88]. The organic carbon on the other hand was 30–65% and the rest were sulfates and nitrates. A constant nucleation mode over a test cycle (1013 #/km, e.g., 107 #/cm3 with mean size 20 nm) would correspond to only 0.1 mg/km (<10 μg on the filter at the end of the cycle). To put these numbers into context, the current SPN limit is 6 × 1011 #/km, with the mass limit at 4.5 mg/km. For heavy-duty vehicles, the same number concentration (107 #/cm3) would translate to >5 times higher emissions due to the higher exhaust flow rate.
There is a significant body of studies that have measured both solid and total number concentrations. For example, large projects funded by the industry [140], and the European Commission, such as the Particulates project which ended in 2004 [141], showed small differences between TPN and SPN at low speeds, but high at high speeds. Other smaller scale studies reported differences of 50–100% between TPN and SPN for Euro1–4 vehicles [74] or recent Euro 5 and Euro 6 [142] or 2009–2012 model years [143] for typical cycles. A review showed that for type approval cycles the trends for solid particles were followed also for total particles (i.e., decreasing for GDIs, no decrease for PFIs) [134]. This decrease is not always so evident in real life [59]. For example, during cold start of gasoline and gas engines nucleation mode particles can be formed [144][145], but not always [146]. Relatively high differences have been reported when fuel specifications change [133][147], and at high speed cycles [143][148][149]. Even for the same vehicle and fuel, different operating points can result to varying TPN/SPN ratios [150][151]. Recent research projects, such as the DownToTen (DTT), which ended in 2020, presented results from many vehicles where the TPN emissions were more than one order of magnitude higher than the SPN [152]. Of particular interest were cases such as gasoline vehicles with GPF, compressed natural gas (CNG) vehicles with and without particulate filter and plug-in hybrids that all under certain conditions exhibited a large range of TPN/SPN values. Another study found more than one order of magnitude higher TPN than SPN for hybrid vehicles even at city driving [153]. All studies mentioned conducted measurements directly from the tailpipe so any volatile particles cannot be attributed to desorption artifacts from the sampling lines.
Similar conclusions have been also drawn for heavy duty engines [154]. A study showed that the total particle number emissions increased from 1011 #/km to 1013 #/km when the exhaust gas temperature was >310 °C [155]. In general, due to the high exhaust gas temperatures and consequently high release of desorbed species from the aftertreatment devices and exhaust line, and high SO2 to SO3 conversion, high TPN concentrations are reported [36][49][156]. Tests with L-category vehicles (e.g., mopeds and motorcycles) also resulted in high TPN, especially at high speeds [135][157]. Different combustion technologies (e.g., temperature reactivity controlled compression ignition (RCCI), hot or low exhaust gas recirculation (EGR) combustion etc.) can also have various TPN to SPN ratios [158].
Specific events, such as DPF regeneration can also produce high concentrations of both solid and semi-volatile particles [155][159][160][161][162][163]. SPN emissions can reach or even exceed the limit of 6 × 1011 #/km [160][163], while total particle emissions can be one to three orders of magnitude higher (up to 2 × 1014 #/km) [73][160][163]. Studies with light-duty and heavy-duty vehicles have also shown that even when the emissions during regeneration events are considered, the weighted (over regeneration distance) solid particle number emissions remain below the current SPN limit [36][164][165]. The regeneration frequency is on average around 400–500 km, with a tendency of shorter distance for newer vehicles [166]. Regarding semi-volatiles, many studies have shown that the concentration of sulfates and organics in the exhaust increases during regenerations and this is often linked to the formation of a distinct nucleation mode [73][163][167]. However, one study found that increased particle number emissions during DPF regeneration were still by 83–99% lower than those without DPF [90]. Furthermore, considering the regeneration frequency, the apparent total particulate matter filtration efficiency was reduced by less than 2% over the average driving conditions for medium- and heavy-duty diesel vehicles [125]. Still, the weighted (total) particle number concentrations over the regeneration distance can be up to one order of magnitude higher than the current limit for solid particles.
The collected evidence suggests that there can be technologies, fuels, and operation conditions that lead to SPN and TPN levels and trends exhibiting significant deviations. The same evidence also suggests that the metric chosen for regulatory control may influence which technologies are promoted for future vehicles and what specifications for fuels and lubricants are decided. All of these factors will have an impact, not only on the specific metric, but on other co-pollutants as well. Therefore, deciding on the proper metric for particle number control will be decisive for the wider environmental impacts of road transport.
 

This entry is adapted from the peer-reviewed paper 10.3390/atmos13020155

References

  1. World Health Organization. WHO Global Air Quality Guidelines: Particulate Matter (PM2.5 and PM10), Ozone, Nitrogen Dioxide, Sulfur Dioxide and Carbon Monoxide; World Health Organization: Geneva, Switzerland, 2021; ISBN 978-92-4-003422-8.
  2. Wolf, K.; Hoffmann, B.; Andersen, Z.J.; Atkinson, R.W.; Bauwelinck, M.; Bellander, T.; Brandt, J.; Brunekreef, B.; Cesaroni, G.; Chen, J.; et al. Long-term exposure to low-level ambient air pollution and incidence of stroke and coronary heart disease: A pooled analysis of six European cohorts within the ELAPSE project. Lancet Planet. Health 2021, 5, e620–e632.
  3. Manisalidis, I.; Stavropoulou, E.; Stavropoulos, A.; Bezirtzoglou, E. Environmental and Health Impacts of Air Pollution: A Review. Front. Public Health 2020, 8, 14.
  4. Hamanaka, R.B.; Mutlu, G.M. Particulate Matter Air Pollution: Effects on the Cardiovascular System. Front. Endocrinol. 2018, 9, 680.
  5. European Environment Agency. Air Quality in Europe: 2020 Report; Publications Office of the European Union: Luxembourg, 2020.
  6. Zhang, R.; Wang, G.; Guo, S.; Zamora, M.L.; Ying, Q.; Lin, Y.; Wang, W.; Hu, M.; Wang, Y. Formation of Urban Fine Particulate Matter. Chem. Rev. 2015, 115, 3803–3855.
  7. Giechaskiel, B.; Mamakos, A.; Andersson, J.; Dilara, P.; Martini, G.; Schindler, W.; Bergmann, A. Measurement of Automotive Nonvolatile Particle Number Emissions within the European Legislative Framework: A Review. Aerosol Sci. Technol. 2012, 46, 719–749.
  8. Wang, J.M.; Jeong, C.-H.; Zimmerman, N.; Healy, R.M.; Hilker, N.; Evans, G.J. Real-World Emission of Particles from Vehicles: Volatility and the Effects of Ambient Temperature. Environ. Sci. Technol. 2017, 51, 4081–4090.
  9. ICCT. ICCT’s Comments and Technical Recommendations on Future Euro 7/VII Emission Standards; International Council on Clean Transportation: Berlin, Germany, 2021.
  10. Simonen, P.; Kalliokoski, J.; Karjalainen, P.; Rönkkö, T.; Timonen, H.; Saarikoski, S.; Aurela, M.; Bloss, M.; Triantafyllopoulos, G.; Kontses, A.; et al. Characterization of laboratory and real driving emissions of individual Euro 6 light-duty vehicles—Fresh particles and secondary aerosol formation. Environ. Pollut. 2019, 255, 113175.
  11. Rönkkö, T.; Timonen, H. Overview of Sources and Characteristics of Nanoparticles in Urban Traffic-Influenced Areas. J. Alzheimer’s Dis. 2019, 72, 15–28.
  12. Kittelson, D.; Khalek, I.; McDonald, J.; Stevens, J.; Giannelli, R. Particle emissions from mobile sources: Discussion of ultrafine particle emissions and definition. J. Aerosol Sci. 2021, 159, 105881.
  13. Simpson, D.; Fagerli, H.; Colette, A.; van der Gon, H.D.; Dore, C.; Hallquist, M.; Hansson, H.C.; Maas, R.; Rouil, L.; Allemand, N.; et al. How Should Condensables Be Included in PM Emission Inventories Reported to EMEP/CLRTAP? EMEP: Gothenburg, Sweden, 2020.
  14. Giechaskiel, B.; Maricq, M.; Ntziachristos, L.; Dardiotis, C.; Wang, X.; Axmann, H.; Bergmann, A.; Schindler, W. Review of motor vehicle particulate emissions sampling and measurement: From smoke and filter mass to particle number. J. Aerosol Sci. 2014, 67, 48–86.
  15. Harris, S.J.; Maricq, M. Signature size distributions for diesel and gasoline engine exhaust particulate matter. J. Aerosol Sci. 2001, 32, 749–764.
  16. Giechaskiel, B.; Lähde, T.; Gandi, S.; Keller, S.; Kreutziger, P.; Mamakos, A. Assessment of 10-nm Particle Number (PN) Portable Emissions Measurement Systems (PEMS) for Future Regulations. Int. J. Environ. Res. Public Health 2020, 17, 3878.
  17. Khalek, I.A.; Badshah, H.; Premnath, V.; Brezny, R. Solid Particle Number and Ash Emissions from Heavy-Duty Natural Gas and Diesel w/SCRF Engines; SAE International: Warrendale, PA, USA, 2018.
  18. Wang, B.; Lau, Y.-S.; Huang, Y.; Organ, B.; Chuang, H.-C.; Ho, S.S.H.; Qu, L.; Lee, S.-C.; Ho, K.-F. Chemical and toxicological characterization of particulate emissions from diesel vehicles. J. Hazard. Mater. 2020, 405, 124613.
  19. Xing, J.; Shao, L.; Zhang, W.; Peng, J.; Wang, W.; Hou, C.; Shuai, S.; Hu, M.; Zhang, D. Morphology and composition of particles emitted from a port fuel injection gasoline vehicle under real-world driving test cycles. J. Environ. Sci. 2018, 76, 339–348.
  20. Polidori, A.; Hu, S.; Biswas, S.; Delfino, R.J.; Sioutas, C. Real-time characterization of particle-bound polycyclic aromatic hydrocarbons in ambient aerosols and from motor-vehicle exhaust. Atmos. Chem. Phys. 2008, 8, 1277–1291.
  21. Dutcher, D.D.; Stolzenburg, M.R.; Thompson, S.L.; Medrano, J.M.; Gross, D.S.; Kittelson, D.B.; McMurry, P.H. Emissions from Ethanol-Gasoline Blends: A Single Particle Perspective. Atmosphere 2011, 2, 182–200.
  22. Perrone, M.G.; Carbone, C.; Faedo, D.; Ferrero, L.; Maggioni, A.; Sangiorgi, G.; Bolzacchini, E. Exhaust emissions of polycyclic aromatic hydrocarbons, n-alkanes and phenols from vehicles coming within different European classes. Atmos. Environ. 2014, 82, 391–400.
  23. Muñoz, M.; Heeb, N.V.; Haag, R.; Honegger, P.; Zeyer, K.; Mohn, J.; Comte, P.; Czerwinski, J. Bioethanol Blending Reduces Nanoparticle, PAH, and Alkyl- and Nitro-PAH Emissions and the Genotoxic Potential of Exhaust from a Gasoline Direct Injection Flex-Fuel Vehicle. Environ. Sci. Technol. 2016, 50, 11853–11861.
  24. Cao, X.; Hao, X.; Shen, X.; Jiang, X.; Wu, B.; Yao, Z. Emission characteristics of polycyclic aromatic hydrocarbons and nitro-polycyclic aromatic hydrocarbons from diesel trucks based on on-road measurements. Atmos. Environ. 2017, 148, 190–196.
  25. Kwon, S.-B.; Lee, K.W.; Saito, K.; Shinozaki, O.; Seto, T. Size-Dependent Volatility of Diesel Nanoparticles: Chassis Dynamometer Experiments. Environ. Sci. Technol. 2003, 37, 1794–1802.
  26. Rönkkö, T.; Virtanen, A.; Kannosto, J.; Keskinen, J.; Lappi, M.; Pirjola, L. Nucleation Mode Particles with a Nonvolatile Core in the Exhaust of a Heavy Duty Diesel Vehicle. Environ. Sci. Technol. 2007, 41, 6384–6389.
  27. De Filippo, A.; Maricq, M.M. Diesel Nucleation Mode Particles: Semivolatile or Solid? Environ. Sci. Technol. 2008, 42, 7957–7962.
  28. Kirchner, U.; Scheer, V.; Vogt, R.; Kägi, R. TEM study on volatility and potential presence of solid cores in nucleation mode particles from diesel powered passenger cars. J. Aerosol Sci. 2009, 40, 55–64.
  29. Mayer, A.; Czerwinski, J.; Kasper, M.; Ulrich, A.; Mooney, J.J. Metal Oxide Particle Emissions from Diesel and Petrol Engines; SAE International: Warrendale, PA, USA, 2012.
  30. Sgro, L.A.; Sementa, P.; Vaglieco, B.M.; Rusciano, G.; D’Anna, A.; Minutolo, P. Investigating the origin of nuclei particles in GDI engine exhausts. Combust. Flame 2012, 159, 1687–1692.
  31. Liati, A.; Schreiber, D.; Dasilva, Y.A.R.; Eggenschwiler, P.D. Ultrafine particle emissions from modern Gasoline and Diesel vehicles: An electron microscopic perspective. Environ. Pollut. 2018, 239, 661–669.
  32. Seong, H.; Choi, S.; Lee, K. Examination of nanoparticles from gasoline direct-injection (GDI) engines using transmission electron microscopy (TEM). Int. J. Automot. Technol. 2014, 15, 175–181.
  33. Fushimi, A.; Kondo, Y.; Kobayashi, S.; Fujitani, Y.; Saitoh, K.; Takami, A.; Tanabe, K. Chemical composition and source of fine and nanoparticles from recent direct injection gasoline passenger cars: Effects of fuel and ambient temperature. Atmos. Environ. 2016, 124, 77–84.
  34. Kuuluvainen, H.; Karjalainen, P.; Saukko, E.; Ovaska, T.; Sirviö, K.; Honkanen, M.; Olin, M.; Niemi, S.; Keskinen, J.; Rönkkö, T. Nonvolatile ultrafine particles observed to form trimodal size distributions in non-road diesel engine exhaust. Aerosol Sci. Technol. 2020, 54, 1345–1358.
  35. Mamakos, A.; Schwelberger, M.; Fierz, M.; Giechaskiel, B. Effect of selective catalytic reduction on exhaust nonvolatile particle emissions of Euro VI heavy-duty compression ignition vehicles. Aerosol Sci. Technol. 2019, 53, 898–910.
  36. Giechaskiel, B. Solid Particle Number Emission Factors of Euro VI Heavy-Duty Vehicles on the Road and in the Laboratory. Int. J. Environ. Res. Public Health 2018, 15, 304.
  37. Rönkkö, T.; Kuuluvainen, H.; Karjalainen, P.; Keskinen, J.; Hillamo, R.; Niemi, J.; Pirjola, L.; Timonen, H.J.; Saarikoski, S.; Saukko, E.; et al. Traffic is a major source of atmospheric nanocluster aerosol. Proc. Natl. Acad. Sci. USA 2017, 114, 7549–7554.
  38. Alanen, J.; Saukko, E.; Lehtoranta, K.; Murtonen, T.; Timonen, H.; Hillamo, R.; Karjalainen, P.; Kuuluvainen, H.; Harra, J.; Keskinen, J.; et al. The formation and physical properties of the particle emissions from a natural gas engine. Fuel 2015, 162, 155–161.
  39. Maricq, M.M. Chemical characterization of particulate emissions from diesel engines: A review. J. Aerosol Sci. 2007, 38, 1079–1118.
  40. Karjalainen, P.; Pirjola, L.; Heikkilä, J.; Lähde, T.; Tzamkiozis, T.; Ntziachristos, L.; Keskinen, J.; Rönkkö, T. Exhaust particles of modern gasoline vehicles: A laboratory and an on-road study. Atmos. Environ. 2014, 97, 262–270.
  41. Ma, C.; Wu, L.; Mao, H.-J.; Fang, X.-Z.; Wei, N.; Zhang, J.-S.; Yang, Z.-W.; Zhang, Y.-J.; Lv, Z.-Y.; Yang, L. Transient Characterization of Automotive Exhaust Emission from Different Vehicle Types Based on On-Road Measurements. Atmosphere 2020, 11, 64.
  42. Rönkkö, T.; Pirjola, L.; Ntziachristos, L.; Heikkilä, J.; Karjalainen, P.; Hillamo, R.; Keskinen, J. Vehicle Engines Produce Exhaust Nanoparticles Even When Not Fueled. Environ. Sci. Technol. 2014, 48, 2043–2050.
  43. Sirignano, M.; D’Anna, A. Filtration and coagulation efficiency of sub-10 nm combustion-generated particles. Fuel 2018, 221, 298–302.
  44. Gren, L.; Malmborg, V.B.; Falk, J.; Markula, L.; Novakovic, M.; Shamun, S.; Eriksson, A.C.; Kristensen, T.B.; Svenningsson, B.; Tunér, M.; et al. Effects of renewable fuel and exhaust aftertreatment on primary and secondary emissions from a modern heavy-duty diesel engine. J. Aerosol Sci. 2021, 156, 105781.
  45. Liati, A.; Spiteri, A.; Eggenschwiler, P.D.; Vogel-Schäuble, N. Microscopic investigation of soot and ash particulate matter derived from biofuel and diesel: Implications for the reactivity of soot. J. Nanopart. Res. 2012, 14, 1224.
  46. Muñoz, M.; Haag, R.; Zeyer, K.; Mohn, J.; Comte, P.; Czerwinski, J.; Heeb, N.V. Effects of Four Prototype Gasoline Particle Filters (GPFs) on Nanoparticle and Genotoxic PAH Emissions of a Gasoline Direct Injection (GDI) Vehicle. Environ. Sci. Technol. 2018, 52, 10709–10718.
  47. Kittelson, D.B. Engines and nanoparticles: A review. J. Aerosol Sci. 1998, 29, 575–588.
  48. Uy, D.; Storey, J.; Sluder, C.S.; Barone, T.; Lewis, S.; Jagner, M. Effects of Oil Formulation, Oil Separator, and Engine Speed and Load on the Particle Size, Chemistry, and Morphology of Diesel Crankcase Aerosols. SAE Int. J. Fuels Lubr. 2016, 9, 224–238.
  49. Giechaskiel, B.; Ntziachristos, L.; Samaras, Z.; Casati, R.; Scheer, V.; Vogt, R. Effect of Speed and Speed-Transition on the Formation of Nucleation Mode Particles from a Light Duty Diesel Vehicle; SAE International: Warrendale, PA, USA, 2007.
  50. Suarez-Bertoa, R.; Mendoza-Villafuerte, P.; Riccobono, F.; Vojtisek, M.; Pechout, M.; Perujo, A.; Astorga, C. On-road measurement of NH3 emissions from gasoline and diesel passenger cars during real world driving conditions. Atmos. Environ. 2017, 166, 488–497.
  51. Selleri, T.; Melas, A.; Joshi, A.; Manara, D.; Perujo, A.; Suarez-Bertoa, R. An Overview of Lean Exhaust deNOx Aftertreatment Technologies and NOx Emission Regulations in the European Union. Catalysts 2021, 11, 404.
  52. Charron, A.; Harrison, R.M. Primary particle formation from vehicle emissions during exhaust dilution in the roadside atmosphere. Atmos. Environ. 2003, 37, 4109–4119.
  53. Casati, R.; Scheer, V.; Vogt, R.; Benter, T. Measurement of nucleation and soot mode particle emission from a diesel passenger car in real world and laboratory in situ dilution. Atmos. Environ. 2007, 41, 2125–2135.
  54. Uhrner, U.; Zallinger, M.; von Löwis, S.; Vehkamäki, H.; Wehner, B.; Stratmann, F.; Wiedensohler, A. Volatile Nanoparticle Formation and Growth within a Diluting Diesel Car Exhaust. J. Air Waste Manag. Assoc. 2011, 61, 399–408.
  55. Tsai, J.-H.; Chang, S.-Y.; Chiang, H.-L. Volatile organic compounds from the exhaust of light-duty diesel vehicles. Atmos. Environ. 2012, 61, 499–506.
  56. Rönkkö, T.; Lähde, T.; Heikkilä, J.; Pirjola, L.; Bauschke, U.; Arnold, F.; Schlager, H.; Rothe, D.; Yli-Ojanperä, J.; Keskinen, J. Effects of Gaseous Sulphuric Acid on Diesel Exhaust Nanoparticle Formation and Characteristics. Environ. Sci. Technol. 2013, 47, 11882–11889.
  57. Kittelson, D.; Watts, W.; Johnson, J.; Rowntree, C.; Payne, M.; Goodier, S.; Warrens, C.; Preston, H.; Zink, U.; Ortiz, M.; et al. On-road evaluation of two Diesel exhaust aftertreatment devices. J. Aerosol Sci. 2006, 37, 1140–1151.
  58. Rodríguez, S.; Cuevas, E. The contributions of “minimum primary emissions” and “new particle formation enhancements” to the particle number concentration in urban air. J. Aerosol Sci. 2007, 38, 1207–1219.
  59. Zhou, L.; Hallquist, Å.M.; Hallquist, M.; Salvador, C.M.; Gaita, S.M.; Sjödin, Å.; Jerksjö, M.; Salberg, H.; Wängberg, I.; Mellqvist, J.; et al. A transition of atmospheric emissions of particles and gases from on-road heavy-duty trucks. Atmos. Chem. Phys. 2020, 20, 1701–1722.
  60. Vaaraslahti, K.; Virtanen, A.; Ristimäki, J.; Keskinen, J. Nucleation Mode Formation in Heavy-Duty Diesel Exhaust with and without a Particulate Filter. Environ. Sci. Technol. 2004, 38, 4884–4890.
  61. Giechaskiel, B.; Ntziachristos, L.; Samaras, Z.; Scheer, V.; Casati, R.; Vogt, R. Formation potential of vehicle exhaust nucleation mode particles on-road and in the laboratory. Atmos. Environ. 2005, 39, 3191–3198.
  62. Vaaraslahti, K.; Keskinen, J.; Giechaskiel, B.; Solla, A.; Murtonen, T.; Vesala, H. Effect of Lubricant on the Formation of Heavy-Duty Diesel Exhaust Nanoparticles. Environ. Sci. Technol. 2005, 39, 8497–8504.
  63. Vouitsis, E.; Ntziachristos, L.; Samaras, Z. Modelling of diesel exhaust aerosol during laboratory sampling. Atmos. Environ. 2005, 39, 1335–1345.
  64. Du, H.; Yu, F. Nanoparticle formation in the exhaust of vehicles running on ultra-low sulfur fuel. Atmos. Chem. Phys. Discuss. 2008, 8, 4729–4739.
  65. Lemmetty, M.; Rönkkö, T.; Virtanen, A.; Keskinen, J.; Pirjola, L. The Effect of Sulphur in Diesel Exhaust Aerosol: Models Compared with Measurements. Aerosol Sci. Technol. 2008, 42, 916–929.
  66. Olin, M.; Rönkkö, T.; Maso, M.D. CFD modeling of a vehicle exhaust laboratory sampling system: Sulfur-driven nucleation and growth in diluting diesel exhaust. Atmos. Chem. Phys. Discuss. 2015, 15, 5305–5323.
  67. Sakurai, H.; Tobias, H.; Park, K.; Zarling, D.; Docherty, K.S.; Kittelson, D.B.; McMurry, P.H.; Ziemann, P.J. On-line measurements of diesel nanoparticle composition and volatility. Atmos. Environ. 2003, 37, 1199–1210.
  68. Park, G.; Mun, S.; Hong, H.; Chung, T.; Jung, S.; Kim, S.; Seo, S.; Kim, J.; Lee, J.; Kim, K.; et al. Characterization of Emission Factors Concerning Gasoline, LPG, and Diesel Vehicles via Transient Chassis-Dynamometer Tests. Appl. Sci. 2019, 9, 1573.
  69. Ristimäki, J.; Lehtoranta, K.; Lappi, M.; Keskinen, J. Hydrocarbon Condensation in Heavy-Duty Diesel Exhaust. Environ. Sci. Technol. 2007, 41, 6397–6402.
  70. Pirjola, L.; Karjalainen, P.; Heikkilä, J.; Saari, S.; Tzamkiozis, T.; Ntziachristos, L.; Kulmala, K.; Keskinen, J.; Rönkkö, T. Effects of Fresh Lubricant Oils on Particle Emissions Emitted by a Modern Gasoline Direct Injection Passenger Car. Environ. Sci. Technol. 2015, 49, 3644–3652.
  71. Vogt, R.; Scheer, V.; Casati, R.; Benter, T. On-Road Measurement of Particle Emission in the Exhaust Plume of a Diesel Passenger Car. Environ. Sci. Technol. 2003, 37, 4070–4076.
  72. Kostenidou, E.; Martinez-Valiente, A.; R’Mili, B.; Marques, B.; Temime-Roussel, B.; Durand, A.; André, M.; Liu, Y.; Louis, C.; Vansevenant, B.; et al. Technical note: Emission factors, chemical composition, and morphology of particles emitted from Euro 5 diesel and gasoline light-duty vehicles during transient cycles. Atmos. Chem. Phys. 2021, 21, 4779–4796.
  73. Bergmann, M.; Kirchner, U.; Vogt, R.; Benter, T. On-road and laboratory investigation of low-level PM emissions of a modern diesel particulate filter equipped diesel passenger car. Atmos. Environ. 2009, 43, 1908–1916.
  74. Tzamkiozis, T.; Ntziachristos, L.; Samaras, Z. Diesel passenger car PM emissions: From Euro 1 to Euro 4 with particle filter. Atmos. Environ. 2010, 44, 909–916.
  75. Keskinen, J.; Rönkkö, T. Can Real-World Diesel Exhaust Particle Size Distribution be Reproduced in the Laboratory? A Critical Review Jorma Keskinen. J. Air Waste Manag. Assoc. 2010, 60, 1245–1255.
  76. Lu, T.; Cheung, C.S.; Huang, Z. Size-Resolved Volatility, Morphology, Nanostructure, and Oxidation Characteristics of Diesel Particulate. Energy Fuels 2012, 26, 6168–6176.
  77. Pang, Y.; Fuentes, M.; Rieger, P. Trends in the emissions of Volatile Organic Compounds (VOCs) from light-duty gasoline vehicles tested on chassis dynamometers in Southern California. Atmos. Environ. 2013, 83, 127–135.
  78. Yang, J.; Roth, P.; Zhu, H.; Durbin, T.D.; Karavalakis, G. Impacts of gasoline aromatic and ethanol levels on the emissions from GDI vehicles: Part 2. Influence on particulate matter, black carbon, and nanoparticle emissions. Fuel 2019, 252, 812–820.
  79. Clairotte, M.; Adam, T.; Zardini, A.; Manfredi, U.; Martini, G.; Krasenbrink, A.; Vicet, A.; Tournié, E.; Astorga, C. Effects of low temperature on the cold start gaseous emissions from light duty vehicles fuelled by ethanol-blended gasoline. Appl. Energy 2013, 102, 44–54.
  80. Sonntag, D.B.; Bailey, C.R.; Fulper, C.R.; Baldauf, R.W. Contribution of Lubricating Oil to Particulate Matter Emissions from Light-Duty Gasoline Vehicles in Kansas City. Environ. Sci. Technol. 2012, 46, 4191–4199.
  81. Amirante, R.; Distaso, E.; Napolitano, M.; Tamburrano, P.; Di Iorio, S.; Sementa, P.; Vaglieco, B.M.; Reitz, R.D. Effects of lubricant oil on particulate emissions from port-fuel and direct-injection spark-ignition engines. Int. J. Engine Res. 2017, 18, 606–620.
  82. Distaso, E.; Amirante, R.; Calò, G.; De Palma, P.; Tamburrano, P. Evolution of Soot Particle Number, Mass and Size Distribution along the Exhaust Line of a Heavy-Duty Engine Fueled with Compressed Natural Gas. Energies 2020, 13, 3993.
  83. Karavalakis, G.; Durbin, T.D.; Yang, J.; Ventura, L.; Xu, K. Fuel Effects on PM Emissions from Different Vehicle/Engine Configurations: A Literature Review; SAE International: Warrendale, PA, USA, 2018.
  84. Lu, Q.; Zhao, Y.; Robinson, A.L. Comprehensive organic emission profiles for gasoline, diesel, and gas-turbine engines including intermediate and semi-volatile organic compound emissions. Atmos. Chem. Phys. 2018, 18, 17637–17654.
  85. Cheung, K.L.; Polidori, A.; Ntziachristos, L.; Tzamkiozis, T.; Samaras, Z.; Cassee, F.R.; Gerlofs, M.; Sioutas, C. Chemical Characteristics and Oxidative Potential of Particulate Matter Emissions from Gasoline, Diesel, and Biodiesel Cars. Environ. Sci. Technol. 2009, 43, 6334–6340.
  86. Giechaskiel, B.; Melas, A.D.; Lähde, T.; Martini, G. Non-Volatile Particle Number Emission Measurements with Catalytic Strippers: A Review. Vehicles 2020, 2, 342–364.
  87. Khalek, I.A.; Bougher, T.L.; Merritt, P.M.; Zielinska, B. Regulated and Unregulated Emissions from Highway Heavy-Duty Diesel Engines Complying with U.S. Environmental Protection Agency 2007 Emissions Standards. J. Air Waste Manag. Assoc. 2011, 61, 427–442.
  88. Khalek, I.A.; Blanks, M.G.; Merritt, P.M.; Zielinska, B. Regulated and unregulated emissions from modern 2010 emissions-compliant heavy-duty on-highway diesel engines. J. Air Waste Manag. Assoc. 2015, 65, 987–1001.
  89. Zeraati-Rezaei, S.; Alam, M.S.; Xu, H.; Beddows, D.C.; Harrison, R.M. Size-resolved physico-chemical characterization of diesel exhaust particles and efficiency of exhaust aftertreatment. Atmos. Environ. 2019, 222, 117021.
  90. Huang, L.; Bohac, S.V.; Chernyak, S.M.; Batterman, S.A. Effects of fuels, engine load and exhaust after-treatment on diesel engine SVOC emissions and development of SVOC profiles for receptor modeling. Atmos. Environ. 2014, 102, 228–238.
  91. Alanen, J.; Simonen, P.; Saarikoski, S.; Timonen, H.; Kangasniemi, O.; Saukko, E.; Hillamo, R.; Lehtoranta, K.; Murtonen, T.; Vesala, H.; et al. Comparison of primary and secondary particle formation from natural gas engine exhaust and of their volatility characteristics. Atmos. Chem. Phys. 2017, 17, 8739–8755.
  92. Li, Y.; Xue, J.; Peppers, J.; Kado, N.Y.; Vogel, C.F.; Alaimo, C.P.; Green, P.G.; Zhang, R.; Jenkins, B.M.; Kim, M.; et al. Chemical and Toxicological Properties of Emissions from a Light-Duty Compressed Natural Gas Vehicle Fueled with Renewable Natural Gas. Environ. Sci. Technol. 2021, 55, 2820–2830.
  93. Rönkkö, T.; Virtanen, A.; Lehtoranta, K.; Keskinen, J.; Pirjola, L.; Lappi, M. Effect of dilution conditions and driving parameters on nucleation mode particles in diesel exhaust: Laboratory and on-road study. Atmos. Environ. 2006, 40, 2893–2901.
  94. Ntziachristos, L.; Ning, Z.; Geller, M.D.; Sioutas, C. Particle Concentration and Characteristics near a Major Freeway with Heavy-Duty Diesel Traffic. Environ. Sci. Technol. 2007, 41, 2223–2230.
  95. Zhang, K.M.; Wexler, A.S. Evolution of particle number distribution near roadways—Part I: Analysis of aerosol dynamics and its implications for engine emission measurement. Atmos. Environ. 2004, 38, 6643–6653.
  96. Kwak, J.H.; Kim, H.S.; Lee, J.H.; Lee, S.H. On-road chasing measurement of exhaust particle emissions from diesel, CNG, LPG, and DME-fueled vehicles using a mobile emission laboratory. Int. J. Automot. Technol. 2014, 15, 543–551.
  97. Shen, X.; Yao, Z.; He, K.; Cao, X.; Liu, H. The Construction and Application of a Multipoint Sampling System for Vehicle Exhaust Plumes. Aerosol Air Qual. Res. 2017, 17, 1705–1716.
  98. Sasaki, S.; Nakajima, T. Study on the Measuring Method of Vehicular PM Size Distribution to Simulate the Atmospheric Dilution Process; SAE International: Warrendale, PA, USA, 2002.
  99. Lee, S.H.; Kwak, J.H.; Lee, J.H. On-road chasing and laboratory measurements of exhaust particle emissions of diesel vehicles equipped with aftertreatment technologies (DPF, urea-SCR). Int. J. Automot. Technol. 2015, 16, 551–559.
  100. Harrison, R.M.; MacKenzie, A.R.; Xu, H.; Alam, M.S.; Nikolova, I.; Zhong, J.; Singh, A.; Zeraati-Rezaei, S.; Stark, C.; Beddows, D.; et al. Diesel exhaust nanoparticles and their behaviour in the atmosphere. Proc. R. Soc. A Math. Phys. Eng. Sci. 2018, 474, 20180492.
  101. Saha, P.K.; Khlystov, A.; Snyder, M.G.; Grieshop, A.P. Characterization of air pollutant concentrations, fleet emission factors, and dispersion near a North Carolina interstate freeway across two seasons. Atmos. Environ. 2018, 177, 143–153.
  102. Choi, W.; Paulson, S.E. Closing the ultrafine particle number concentration budget at road-to-ambient scale: Implications for particle dynamics. Aerosol Sci. Technol. 2016, 50, 448–461.
  103. Fushimi, A.; Hasegawa, S.; Takahashi, K.; Fujitani, Y.; Tanabe, K.; Kobayashi, S. Atmospheric fate of nuclei-mode particles estimated from the number concentrations and chemical composition of particles measured at roadside and background sites. Atmos. Environ. 2008, 42, 949–959.
  104. Zimmerman, N.; Wang, J.M.; Jeong, C.-H.; Ramos, M.; Hilker, N.; Healy, R.M.; Sabaliauskas, K.; Wallace, J.S.; Evans, G.J. Field Measurements of Gasoline Direct Injection Emission Factors: Spatial and Seasonal Variability. Environ. Sci. Technol. 2016, 50, 2035–2043.
  105. Kangasniemi, O.; Kuuluvainen, H.; Heikkilä, J.; Pirjola, L.; Niemi, J.V.; Timonen, H.; Saarikoski, S.; Rönkkö, T.; Maso, M.D. Dispersion of a Traffic Related Nanocluster Aerosol Near a Major Road. Atmosphere 2019, 10, 309.
  106. Kumar, P.; Ketzel, M.; Vardoulakis, S.; Pirjola, L.; Britter, R. Dynamics and dispersion modelling of nanoparticles from road traffic in the urban atmospheric environment—A review. J. Aerosol Sci. 2011, 42, 580–603.
  107. Carpentieri, M.; Kumar, P. Ground-fixed and on-board measurements of nanoparticles in the wake of a moving vehicle. Atmos. Environ. 2011, 45, 5837–5852.
  108. Liu, H.; Qi, L.; Liang, C.; Deng, F.; Man, H.; He, K. How aging process changes characteristics of vehicle emissions? A review. Crit. Rev. Environ. Sci. Technol. 2019, 50, 1796–1828.
  109. Hidy, G.M. Atmospheric Chemistry in a Box or a Bag. Atmosphere 2019, 10, 401.
  110. Ahlberg, E.; Ausmeel, S.; Eriksson, A.; Holst, T.; Karlsson, T.; Brune, W.H.; Frank, G.; Roldin, P.; Kristensson, A.; Svenningsson, B. No Particle Mass Enhancement from Induced Atmospheric Ageing at a Rural Site in Northern Europe. Atmosphere 2019, 10, 408.
  111. Suarez-Bertoa, R.; Zardini, A.; Platt, S.; Hellebust, S.; Pieber, S.M.; El Haddad, I.; Temime-Roussel, B.; Baltensperger, U.; Marchand, N.; Prevot, A.; et al. Primary emissions and secondary organic aerosol formation from the exhaust of a flex-fuel (ethanol) vehicle. Atmos. Environ. 2015, 117, 200–211.
  112. Karjalainen, P.; Timonen, H.; Saukko, E.; Kuuluvainen, H.; Saarikoski, S.; Aakko-Saksa, P.; Murtonen, T.; Bloss, M.; Maso, M.D.; Simonen, P.; et al. Time-resolved characterization of primary particle emissions and secondary particle formation from a modern gasoline passenger car. Atmos. Chem. Phys. 2016, 16, 8559–8570.
  113. Roth, P.; Yang, J.; Peng, W.; Cocker, D.R.; Durbin, T.D.; Asa-Awuku, A.; Karavalakis, G. Intermediate and high ethanol blends reduce secondary organic aerosol formation from gasoline direct injection vehicles. Atmos. Environ. 2019, 220, 117064.
  114. Chirico, R.; Clairotte, M.; Adam, T.W.; Giechaskiel, B.; Heringa, M.F.; Elsasser, M.; Martini, G.; Manfredi, U.; Streibel, T.; Sklorz, M.; et al. Emissions of Organic Aerosol Mass, Black Carbon, Particle Number, and Regulated and Unregulated Gases from Scooters and Light and Heavy Duty Vehicles with Different Fuels. Atmos. Chem. Phys. Discuss. 2014, 14, 16591–16639.
  115. Deng, W.; Hu, Q.; Liu, T.; Wang, X.; Zhang, Y.; Song, W.; Sun, Y.; Bi, X.; Yu, J.; Yang, W.; et al. Primary particulate emissions and secondary organic aerosol (SOA) formation from idling diesel vehicle exhaust in China. Sci. Total Environ. 2017, 593–594, 462–469.
  116. Zhao, Y.; Lambe, A.T.; Saleh, R.; Saliba, G.; Robinson, A.L. Secondary Organic Aerosol Production from Gasoline Vehicle Exhaust: Effects of Engine Technology, Cold Start, and Emission Certification Standard. Environ. Sci. Technol. 2018, 52, 1253–1261.
  117. Vu, D.; Roth, P.; Berte, T.; Yang, J.; Cocker, D.; Durbin, T.D.; Karavalakis, G.; Asa-Awuku, A. Using a new Mobile Atmospheric Chamber (MACh) to investigate the formation of secondary aerosols from mobile sources: The case of gasoline direct injection vehicles. J. Aerosol Sci. 2019, 133, 1–11.
  118. Du, Z.; Hu, M.; Peng, J.; Zhang, W.; Zheng, J.; Gu, F.; Qin, Y.; Yang, Y.; Li, M.; Wu, Y.; et al. Comparison of primary aerosol emission and secondary aerosol formation from gasoline direct injection and port fuel injection vehicles. Atmos. Chem. Phys. 2018, 18, 9011–9023.
  119. Gordon, T.D.; Presto, A.A.; May, A.A.; Nguyen, N.T.; Lipsky, E.M.; Donahue, N.M.; Gutierrez, A.; Zhang, M.; Maddox, C.; Rieger, P.; et al. Secondary organic aerosol formation exceeds primary particulate matter emissions for light-duty gasoline vehicles. Atmos. Chem. Phys. 2014, 14, 4661–4678.
  120. Gentner, D.R.; Jathar, S.H.; Gordon, T.D.; Bahreini, R.; Day, D.; El Haddad, I.; Hayes, P.L.; Pieber, S.M.; Platt, S.; de Gouw, J.; et al. Review of Urban Secondary Organic Aerosol Formation from Gasoline and Diesel Motor Vehicle Emissions. Environ. Sci. Technol. 2017, 51, 1074–1093.
  121. Timonen, H.; Karjalainen, P.; Saukko, E.; Saarikoski, S.; Aakko-Saksa, P.; Simonen, P.; Murtonen, T.; Maso, M.D.; Kuuluvainen, H.; Bloss, M.; et al. Influence of fuel ethanol content on primary emissions and secondary aerosol formation potential for a modern flex-fuel gasoline vehicle. Atmos. Chem. Phys. 2017, 17, 5311–5329.
  122. Karjalainen, P.; Rönkkö, T.; Simonen, P.; Ntziachristos, L.; Juuti, P.; Timonen, H.; Teinilä, K.; Saarikoski, S.; Saveljeff, H.; Lauren, M.; et al. Strategies to Diminish the Emissions of Particles and Secondary Aerosol Formation from Diesel Engines. Environ. Sci. Technol. 2019, 53, 10408–10416.
  123. Gramsch, E.; Papapostolou, V.; Reyes, F.; Vásquez, Y.; Castillo, M.; Oyola, P.; López, G.; Cádiz, A.; Ferguson, S.; Wolfson, M.; et al. Variability in the primary emissions and secondary gas and particle formation from vehicles using bioethanol mixtures. J. Air Waste Manag. Assoc. 2018, 68, 329–346.
  124. May, A.A.; Nguyen, N.T.; Presto, A.A.; Gordon, T.; Lipsky, E.M.; Karve, M.; Gutierrez, A.; Robertson, W.H.; Zhang, M.; Brandow, C.; et al. Gas- and particle-phase primary emissions from in-use, on-road gasoline and diesel vehicles. Atmos. Environ. 2014, 88, 247–260.
  125. Gordon, T.D.; Presto, A.A.; Nguyen, N.T.; Robertson, W.H.; Na, K.; Sahay, K.N.; Zhang, M.; Maddox, C.; Rieger, P.; Chattopadhyay, S.; et al. Secondary organic aerosol production from diesel vehicle exhaust: Impact of aftertreatment, fuel chemistry and driving cycle. Atmos. Chem. Phys. 2014, 14, 4643–4659.
  126. Mehsein, K.; Norsic, C.; Chaillou, C.; Nicolle, A. Minimizing secondary pollutant formation through identification of most influential volatile emissions in gasoline exhausts: Impact of the vehicle powertrain technology. Atmos. Environ. 2020, 226, 117394.
  127. Park, G.; Kim, K.; Park, T.; Kang, S.; Ban, J.; Choi, S.; Yu, D.-G.; Lee, S.; Lim, Y.; Kim, S.; et al. Primary and secondary aerosols in small passenger vehicle emissions: Evaluation of engine technology, driving conditions, and regulatory standards. Environ. Pollut. 2021, 286, 117195.
  128. Jathar, S.H.; Friedman, B.; Galang, A.A.; Link, M.F.; Brophy, P.; Volckens, J.; Eluri, S.; Farmer, D.K. Linking Load, Fuel, and Emission Controls to Photochemical Production of Secondary Organic Aerosol from a Diesel Engine. Environ. Sci. Technol. 2017, 51, 1377–1386.
  129. Bahreini, R.; Middlebrook, A.; de Gouw, J.; Warneke, C.; Trainer, M.; Brock, C.A.; Stark, H.; Brown, S.S.; Dube, W.P.; Gilman, J.B.; et al. Gasoline emissions dominate over diesel in formation of secondary organic aerosol mass. Geophys. Res. Lett. 2012, 39, L06805.
  130. Platt, S.M.; El Haddad, I.; Zardini, A.A.; Clairotte, M.; Astorga, C.; Wolf, R.; Slowik, J.G.; Temime-Roussel, B.; Marchand, N.; Ježek, I.; et al. Secondary organic aerosol formation from gasoline vehicle emissions in a new mobile environmental reaction chamber. Atmos. Chem. Phys. 2013, 13, 9141–9158.
  131. Pieber, S.M.; Kumar, N.K.; Klein, F.; Comte, P.; Bhattu, D.; Dommen, J.; Bruns, E.A.; Kılıç, D.; El Haddad, I.; Keller, A.; et al. Gas-phase composition and secondary organic aerosol formation from standard and particle filter-retrofitted gasoline direct injection vehicles investigated in a batch and flow reactor. Atmos. Chem. Phys. 2018, 18, 9929–9954.
  132. Kuittinen, N.; McCaffery, C.; Peng, W.; Zimmerman, S.; Roth, P.; Simonen, P.; Karjalainen, P.; Keskinen, J.; Cocker, D.R.; Durbin, T.D.; et al. Effects of driving conditions on secondary aerosol formation from a GDI vehicle using an oxidation flow reactor. Environ. Pollut. 2021, 282, 117069.
  133. Kuittinen, N.; McCaffery, C.; Zimmerman, S.; Bahreini, R.; Simonen, P.; Karjalainen, P.; Keskinen, J.; Rönkkö, T.; Karavalakis, G. Using an oxidation flow reactor to understand the effects of gasoline aromatics and ethanol levels on secondary aerosol formation. Environ. Res. 2021, 200, 111453.
  134. Giechaskiel, B.; Joshi, A.; Ntziachristos, L.; Dilara, P. European Regulatory Framework and Particulate Matter Emissions of Gasoline Light-Duty Vehicles: A Review. Catalysts 2019, 9, 586.
  135. Kontses, A.; Ntziachristos, L.; Zardini, A.; Papadopoulos, G.; Giechaskiel, B. Particulate emissions from L-Category vehicles towards Euro 5. Environ. Res. 2019, 182, 109071.
  136. Giechaskiel, B.; Zardini, A.A.; Lähde, T.; Perujo, A.; Kontses, A.; Ntziachristos, L. Particulate Emissions of Euro 4 Motorcycles and Sampling Considerations. Atmosphere 2019, 10, 421.
  137. Bagley, S.T.; Baumgard, K.; Gratz, L.; Johnson, J.H.; Leddy, D. Haracterization of Fuel and Aftertreatment Device Effects on Diesel Emissions. Res. Rep. Health Eff. Inst. 1996, 76, 1–75.
  138. Vouitsis, E.; Ntziachristos, L.; Samaras, Z. Theoretical Investigation of the Nucleation Mode Formation Downstream of Diesel After-treatment Devices. Aerosol Air Qual. Res. 2008, 8, 37–53.
  139. de Jesus, A.L.; Rahman, M.; Mazaheri, M.; Thompson, M.; Knibbs, L.; Jeong, C.; Evans, G.; Nei, W.; Ding, A.; Qiao, L.; et al. Ultrafine particles and PM2.5 in the air of cities around the world: Are they representative of each other? Environ. Int. 2019, 129, 118–135.
  140. Mohr, M.; Lehmann, U.; Margaria, G. ACEA Programme on the Emissions of Fine Particulates from Passenger Cars(2) Part1: Particle Characterisation of a Wide Range of Engine Technologies; SAE International: Warrendale, PA, USA, 2003.
  141. Ntziachristos, L.; Mamakos, A.; Samaras, Z.; Mathis, U.; Mohr, M.; Thompson, N.; Stradling, R.; Forti, L.; De Serves, C. Overview of the European “Particulates” Project on the Characterization of Exhaust Particulate Emissions from Road Vehicles: Results for Light-Duty Vehicles; SAE International: Warrendale, PA, USA, 2004.
  142. Giechaskiel, B.; Vanhanen, J.; Väkevä, M.; Martini, G. Investigation of vehicle exhaust sub-23 nm particle emissions. Aerosol Sci. Technol. 2017, 51, 626–641.
  143. Xue, J.; Li, Y.; Quiros, D.; Hu, S.; Huai, T.; Ayala, A.; Jung, H.S. Investigation of alternative metrics to quantify PM mass emissions from light duty vehicles. J. Aerosol Sci. 2017, 113, 85–94.
  144. Kontses, A.; Triantafyllopoulos, G.; Ntziachristos, L.; Samaras, Z. Particle number (PN) emissions from gasoline, diesel, LPG, CNG and hybrid-electric light-duty vehicles under real-world driving conditions. Atmos. Environ. 2019, 222, 117126.
  145. Li, W.; Collins, J.F.; Norbeck, J.M.; Cocker, D.R.; Sawant, A. Assessment of Particulate Matter Emissions from a Smple of In-Use ULEV and SULEV Vehicles; SAE International: Warrendale, PA, USA, 2006.
  146. Badshah, H.; Kittelson, D.; Northrop, W. Particle Emissions from Light-Duty Vehicles during Cold-Cold Start. SAE Int. J. Engines 2016, 9, 1775–1785.
  147. Karavalakis, G.; Short, D.; Chen, V.; Espinoza, C.; Berte, T.; Durbin, T.; Asa-Awuku, A.; Jung, H.; Ntziachristos, L.; Amanatidis, S.; et al. Evaluating Particulate Emissions from a Flexible Fuel Vehicle with Direct Injection when Operated on Ethanol and Iso-Butanol Blends; SAE International: Warrendale, PA, USA, 2014.
  148. Maricq, M.M.; Szente, J.J.; Harwell, A.L.; Loos, M.J. Impact of aggressive drive cycles on motor vehicle exhaust PM emissions. J. Aerosol Sci. 2017, 113, 1–11.
  149. Hu, Z.; Lu, Z.; Song, B.; Quan, Y. Impact of test cycle on mass, number and particle size distribution of particulates emitted from gasoline direct injection vehicles. Sci. Total Environ. 2020, 762, 143128.
  150. Larsson, T.; Prasath, A.; Olofsson, U.; Erlandsson, A. Undiluted Measurement of Sub 10 nm Non-Volatile and Volatile Particle Emissions from a DISI Engine Fueled with Gasoline and Ethanol; SAE International: Warrendale, PA, USA, 2021.
  151. Di Iorio, S.; Catapano, F.; Magno, A.; Sementa, P.; Vaglieco, B.M. Investigation on sub-23 nm particles and their volatile organic fraction (VOF) in PFI/DI spark ignition engine fueled with gasoline, ethanol and a 30% v/v ethanol blend. J. Aerosol Sci. 2020, 153, 105723.
  152. Samaras, Z.C.; Andersson, J.; Bergmann, A.; Hausberger, S.; Toumasatos, Z.; Keskinen, J.; Haisch, C.; Kontses, A.; Ntziachristos, L.D.; Landl, L.; et al. Measuring Automotive Exhaust Particles Down to 10 nm. SAE Int. J. Adv. Curr. Pract. Mobil. 2020, 3, 539–550.
  153. Li, C.; Swanson, J.; Pham, L.; Hu, S.; Hu, S.; Mikailian, G.; Jung, H.S. Real-world particle and NOx emissions from hybrid electric vehicles under cold weather conditions. Environ. Pollut. 2021, 286, 117320.
  154. Thompson, N.; Ntziachristos, L.; Samaras, Z.; Aakko, P.; Wass, U.; Hausberger, S.; Sams, T. Overview of the European “Particulates” Project on the Characterization of Exhaust Particulate Emissions from Road Vehicles: Results for Heavy Duty Engines; SAE International: Warrendale, PA, USA, 2004.
  155. Wang, T.; Quiros, D.C.; Thiruvengadam, A.; Pradhan, S.; Hu, S.; Huai, T.; Lee, E.S.; Zhu, Y. Total Particle Number Emissions from Modern Diesel, Natural Gas, and Hybrid Heavy-Duty Vehicles During On-Road Operation. Environ. Sci. Technol. 2017, 51, 6990–6998.
  156. Swanson, J.J.; Kittelson, D.B.; Watts, W.F.; Gladis, D.D.; Twigg, M.V. Influence of storage and release on particle emissions from new and used CRTs. Atmos. Environ. 2009, 43, 3998–4004.
  157. Giechaskiel, B.; Zardini, A.; Martini, G. Particle Emission Measurements from L-Category Vehicles. SAE Int. J. Engines 2015, 8, 2322–2337.
  158. Premnath, V.; Zavala, B.; Khalek, I.; Eakle, S.; Henry, C. Detailed Characterization of Particle Emissions from Advanced Internal Combustion Engines; SAE International: Warrendale, PA, USA, 2021.
  159. Yamada, H.; Inomata, S.; Tanimoto, H. Mechanisms of Increased Particle and VOC Emissions during DPF Active Regeneration and Practical Emissions Considering Regeneration. Environ. Sci. Technol. 2017, 51, 2914–2923.
  160. Giechaskiel, B. Particle Number Emissions of a Diesel Vehicle during and between Regeneration Events. Catalysts 2020, 10, 587.
  161. R’Mili, B.; Boréave, A.; Meme, A.; Vernoux, P.; Leblanc, M.; Noël, L.; Raux, S.; D’Anna, B. Physico-Chemical Characterization of Fine and Ultrafine Particles Emitted during Diesel Particulate Filter Active Regeneration of Euro5 Diesel Vehicles. Environ. Sci. Technol. 2018, 52, 3312–3319.
  162. Leblanc, M.; Noel, L.; R’Mili, B.; Boréave, A.; D’Anna, B.; Raux, S. Impact of Engine Warm-up and DPF Active Regeneration on Regulated & Unregulated Emissions of a Euro 6 Diesel SCR Equipped Vehicle. J. Earth Sci. Geotech. Eng. 2016, 6, 29–50.
  163. Transport & Environment. New Diesels, New Problems; European Federation for Transport and Environment AISBL: Brussels, Belgium, 2020.
  164. Giechaskiel, B.; Lahde, T.; Suarez-Bertoa, R.; Clairotte, M.; Grigoratos, T.; Zardini, A.; Perujo, A.; Martini, G. Particle number measurements in the European legislation and future JRC activities. Combust. Engines 2018, 174, 3–16.
  165. Giechaskiel, B.; Gioria, R.; Carriero, M.; Lähde, T.; Forloni, F.; Perujo, A.; Martini, G.; Bissi, L.M.; Terenghi, R. Emission Factors of a Euro VI Heavy-duty Diesel Refuse Collection Vehicle. Sustainability 2019, 11, 1067.
  166. Valverde, V.; Giechaskiel, B. Assessment of Gaseous and Particulate Emissions of a Euro 6d-Temp Diesel Vehicle Driven >1300 km Including Six Diesel Particulate Filter Regenerations. Atmosphere 2020, 11, 645.
  167. Bikas, G.; Zervas, E. Regulated and Non-Regulated Pollutants Emitted during the Regeneration of a Diesel Particulate Filter. Energy Fuels 2007, 21, 1543–1547.
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