Characterization of laboratory and real driving emissions of individual Euro 6 light-duty vehicles – Fresh particles and secondary aerosol formation

Emissions from passenger cars are one of major sources that deteriorate urban air quality. This study presents characterization of real-drive emissions from three Euro 6 emission level passenger cars (two gasoline and one diesel) in terms of fresh particles and secondary aerosol formation. The gasoline vehicles were also characterized by chassis dynamometer studies. In the real-drive study, the particle number emissions during regular driving were 1.1–12.7 times greater than observed in the laboratory tests (4.8 times greater on average), which may be caused by more effective nucleation process when diluted by real polluted and humid ambient air. However, the emission factors measured in laboratory were still much higher than the regulatory value of 6 × 10^(11) particles km^(−1). The higher emission factors measured here result probably from the fact that the regulatory limit considers only non-volatile particles larger than 23 nm, whereas here, all particles (also volatile) larger than 3 nm were measured. Secondary aerosol formation potential was the highest after a vehicle cold start when most of the secondary mass was organics. After the cold start, the relative contributions of ammonium, sulfate and nitrate increased. Using a novel approach to study secondary aerosol formation under real-drive conditions with the chase method resulted mostly in emission factors below detection limit, which was not in disagreement with the laboratory findings

HELIOS/SICRIT/mass spectrometry for analysis of aerosols in engine exhaust

Current legislations typically characterize systems of aerosols, such as from vehicle exhaust, primarily by number concentration and size distributions. While potential health threats have a dependence on the particle size, the chemical composition of particles, including the volatile and semi-volatile components adsorbed onto nonvolatile particle cores present at roadside and urban settings, is important in understanding the impact of exhaust particles on health. To date, the only tools suitable for an online in-depth chemical aerosol characterization are aerosol mass spectrometers, which are typically composed of complex and cost intensive instrumentation. We present a new analytical system, which combines a novel inexpensive infrared-radiation-based evaporation system (HELIOS) with a commercially available highly efficient atmospheric ionization source (SICRIT) connected to a rather low-price ion-trap mass spectrometer. Our inexpensive, robust and mobile aerosol characterization HELIOS/SICRIT/Mass Spectrometry system enables highly sensitive chemical analysis of particle-associated volatile substances. We validate the HELIOS/SICRIT/Mass Spectrometry system in laboratory experiments with coated particles generated under controlled conditions, and show that the system is capable of identification of combustion-generated polycyclic aromatic hydrocarbons and relative quantification of individual chemical species adsorbed on particle surfaces. We then employ our system to analyze real-world vehicle engine exhaust aerosol and show through time-resolved measurements with high time resolution (<10 s) that the chemical composition of the particles changes during different parts of an engine test cycle.acceptedVersionPeer reviewe

Nanoparticle emissions from the transport sector: health and policy impacts - the nPETS concept

Road, rail, air, and sea transport generate a major fraction of outdoor ultrafine particles. However, there is no common methodology for comparable sub 100 nm particle emissions measurement. This paper presents the nPETS (grant agreement No 954377) concept to understand and mitigate the effects of emerging non-regulated nanoparticle emissions. This paper presents the concept and selected results. For example, nucleation and condensation mechanisms occur more frequently in the urban background site, leading to new particle formation, while mostly fresh emissions are measured in the traffic site.This work is part of nPETS, a project that has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 954377Peer reviewe

Μέθοδοι και τεχνικές για την αξιολόγηση σωματιδιακών εκπομπών οχημάτων με χρήση εναλλακτικών καυσίμων και εξελιγμένων συστημάτων αντιρρύπανσης

The current PhD Thesis presents the assessment of vehicular exhaust particulate emissions, covering a wide range of different vehicle types (light-duty and L-category vehicles, the latter including 2-, 3-, and light 4-wheelers), fuel types (gasoline, diesel, Liquified Petroleum Gas-LPG, Compressed Natural Gas-CNG and hybrid-electric powertrains), engine and emission control technologies. The method followed comprised emission measurements under laboratory (chassis dynamometer) and real-world driving conditions. The main objective was to identify those cases where particulate control regulation needs to be extended, further to the current coverage of diesel and gasoline direct injection (GDI) technologies. The potential to further decrease particulate emissions of diesel vehicles through fuel refinement was evaluated, with the focus being on latest-technology DPF-equipped passenger cars. Focusing on L-category vehicles (the current and forthcoming regulation prescribe only a particulate mass limit), the results of the current study revealed that, apart from diesel and GDI, high particulate emissions are also observed in other engine technologies. More specifically, vehicles equipped with 2-stroke gasoline engines were found to be high particulate mass (PM) and solid particle number (SPN) emitters, reaching the emission levels of diesel vehicles (without diesel particulate filter). Furthermore, high SPN emissions were also observed in the other L-sub-categories, although their PM emissions were in low levels, already below the respective limits. With regard to light-duty vehicles, the highest SPN emissions (under real-world driving conditions) were observed in the case of gasoline (with port fuel injection-PFI system) and LPG vehicles, especially in old-technology ones, exceeding the regulation limit (although this is not applicable on this engine technology). Diesel vehicles (equipped with DPF) were found to be the lowest emitters, while similar emission levels were observed in the case of the CNG vehicle. SPN emissions from the hybrid-electric vehicle (equipped with gasoline PFI engine) were found to be rather high compared to conventional PFI engines, exceeding the regulation limit (although not applicable also in this case). With regard to the fuel properties effects, the current study revealed that these can significantly affect particulate emissions even in the case of latest-technology DPF-equipped diesel vehicles. Thus, the conclusion of the current study is that in both L-category and light-duty vehicles, regulation focus should be extended to other engine and powertrain technologies, which were found to be high emitters. In the case of L-category vehicles, the PM limit should be extended to 2-stroke engines, while for the other sub-categories the introduction of a SPN limit may be required. In the case of light-duty vehicles, close attention should be focused on old-technology gasoline and LPG vehicles, while even latest technology gasoline (PFI) and hybrid-electric vehicles should also come under scrutiny. Finally, regarding the fuel properties refinement, it is suggested that the regulation limits on fuel properties should be revised in order to take into account the fuel properties effects on particulate emissions from latest-technology vehicles.Η παρούσα διδακτορική διατριβή εστιάζει στην αξιολόγηση των σωματιδιακών εκπομπών οχημάτων, καλύπτοντας ένα ευρύ φάσμα διαφορετικών τύπων οχημάτων (επιβατικά και οχήματα της κατηγορίας «L», δηλαδή δίτροχα, τρίτροχα και ελαφρά τετράτροχα), καυσίμων (πετρέλαιο, βενζίνη, υγραέριο, φυσικό αέριο και ηλεκτρο-υβριδικά οχήματα), τεχνολογιών κινητήρα και συστημάτων αντιρρύπανσης. Η μελέτη βασίζεται σε μετρήσεις ρύπων σε εργαστηριακό περιβάλλον (πέδη οχημάτων) και σε πραγματικές συνθήκες στο δρόμο. Ο κύριος στόχος της διατριβής ήταν να προσδιοριστούν οι τεχνολογίες κινητήρα και τα είδη καυσίμου, στα οποία θα πρέπει να επεκταθεί η υπάρχουσα νομοθεσία, η οποία επικεντρώνεται προς το παρόν μόνο στις σωματιδιακές εκπομπές από πετρελαιοκίνητα οχήματα και από οχήματα με κινητήρα άμεσης έγχυσης καυσίμου. Επιπλέον, αξιολογήθηκε το περιθώριο περαιτέρω μείωσης των σωματιδιακών εκπομπών των σύγχρονων πετρελαιοκίνητων οχημάτων μέσω της αλλαγής των ιδιοτήτων του καυσίμου. Εστιάζοντας αρχικά στα οχήματα της κατηγορίας «L» (η υπάρχουσα και η προσεχής νομοθεσία προβλέπουν όριο εκπομπών μόνο για την μάζα των σωματιδίων), τα αποτελέσματα της έρευνας φανέρωσαν ότι εκτός από τα πετρελαιοκίνητα οχήματα, υψηλές σωματιδιακές εκπομπές (μάζας και αριθμού σωματιδίων) παρατηρούνται και σε άλλες τεχνολογίες κινητήρα. Πιο συγκεκριμένα, οχήματα εφοδιασμένα με δίχρονους βενζινοκινητήρες παρουσίασαν υψηλές εκπομπές μάζας και αριθμού σωματιδίων, κοντά στα επίπεδα των πετρελαιοκίνητων οχημάτων (χωρίς φίλτρο κατακράτησης σωματιδίων), ενώ υψηλές εκπομπές αριθμού σωματιδίων παρατηρήθηκαν και στις υπόλοιπες υποκατηγορίες που μελετήθηκαν, παρόλο που η εκπεμπόμενη μάζα σωματιδίων ήταν σε επίπεδα κάτω από τα νομοθετημένα όρια. Όσον αφορά τα επιβατικά οχήματα, οι υψηλότερες εκπομπές αριθμού σωματιδίων (υπό πραγματικές συνθήκες οδήγησης) παρατηρήθηκαν στα οχήματα βενζίνης (έμμεσης έγχυσης καυσίμου) και υγραερίου, ιδιαίτερα στα παλαιότερης τεχνολογίας, ξεπερνώντας κατά πολύ το όριο της νομοθεσίας (παρόλο που αυτό δεν ισχύει για αυτές τις τεχνολογίες κινητήρα). Πολύ χαμηλές ήταν οι εκπομπές των πετρελαιοκίνητων οχημάτων (χάρη στην τοποθέτηση φίλτρου σωματιδίων) αλλά και του οχήματος φυσικού αερίου που μελετήθηκε. Αξιοσημείωτο είναι το γεγονός ότι οι εκπομπές του ηλεκτρο-υβριδικού οχήματος ήταν σχετικά υψηλές συγκριτικά με συμβατικά οχήματα με κινητήρα έμμεσης έγχυσης καυσίμου, ξεπερνώντας μάλιστα το όριο της νομοθεσίας (το οποίο δεν ισχύει ούτε σε αυτή την τεχνολογία κινητήρα). Όσον αφορά την μελέτη των ιδιοτήτων του καυσίμου, προέκυψε ότι αυτές μπορούν να επηρεάσουν σημαντικά τις σωματιδιακές εκπομπές ακόμα και των σύγχρονων πετρελαιοκίνητων οχημάτων που είναι εφοδιασμένα με φίλτρο κατακράτησης σωματιδίων. Το συμπέρασμα που προκύπτει, λοιπόν, από την παρούσα διδακτορική έρευνα είναι ότι τόσο στα οχήματα της κατηγορίας «L», όσο και στα επιβατικά οχήματα, το ενδιαφέρον της νομοθεσίας θα πρέπει να στραφεί και προς άλλες τεχνολογίες, οι οποίες παρουσίασαν υψηλές σωματιδιακές εκπομπές. Στην περίπτωση των οχημάτων της κατηγορίας «L» το όριο εκπομπών μάζας σωματιδίων θα πρέπει να επεκταθεί και στους δίχρονους κινητήρες, ενώ για τις υπόλοιπες υποκατηγορίες η υιοθέτηση ενός ορίου για τις εκπομπές αριθμού σωματιδίων ίσως είναι απαραίτητη. Στα επιβατικά οχήματα, προσοχή θα πρέπει να δοθεί στα παλαιότερης τεχνολογίας οχήματα βενζίνης και υγραερίου, ενώ στο μικροσκόπιο θα πρέπει επίσης να βρεθούν τα βενζινοκίνητα (έμμεσης έγχυσης καυσίμου) και τα ηλεκτρο-υβριδικά οχήματα τελευταίας τεχνολογίας. Τέλος, όσον αφορά την βελτίωση των ιδιοτήτων του καυσίμου, προτείνεται η αναθεώρηση των ορίων που θέτει η νομοθεσία ώστε να ληφθεί υπόψη και η επίδρασή τους στις σωματιδιακές εκπομπές των οχημάτων τελευταίας τεχνολογίας

Particulate emissions from L-Category vehicles towards Euro 5

The current experimental study presents particulate emissions from 30 Euro 1-4 L-category vehicles (i.e. 2-, 3- and 4-wheelers such as mopeds, motorcycles, quads and minicars, registered in Europe between 2009 and 2016) tested on a chassis dynamometer. The objectives were to identify those sub-categories with high emissions, to assess whether the measures prescribed in the Euro 5 legislation will effectively control particulate emissions and finally to investigate the need for additional measures. The results showed that 2-stroke (2S) mopeds and diesel minicars comprised the vehicles with the highest particulate mass (PM) and solid particle number above 23 nm (SPN23) emissions (up to 64 mg/km and 4.5 × 10^13 p/km, respectively). It is uncertain whether the installation of diesel particulate filters (DPF) is a cost-effective measure for diesel mini-cars in order to comply with Euro 5 standard, while advanced emission controls will be required for 2S mopeds, if such vehicles remain competitive for Euro 5. Regarding 4-stroke mopeds, motorcycles and quads, PM emissions were one order of magnitude lower than 2S ones and already below the Euro 5 limit. Nevertheless, SPN23 emissions from these sub-categories were up to 5 times higher than the Euro 6 passenger cars limit (6×10^11 p/km). Even recent Euro 4 motorcycles eceeded this limit by up to 3 times. These results indicate that L-category vehicles are a significant contributor to vehicular particulate emissions and should be further monitored during and after the introduction of the Euro 5 step. Moreover, including SPN in the range 10–23 nm increases emission levels by up to 2.4 times compared to SPN23, while volatile and semi-volatile particle numbers were even higher. Finally, cold engine operation was found to be a significant contributor on SPN23 emissions, especially for vehicles with lower overall emission levels. These results indicate that a specific particle number limit may be required for L-category to align emissions with passenger cars.JRC.C.4-Sustainable Transpor

Particulate Emissions of Euro 4 Motorcycles and Sampling Considerations

The scientific literature indicates that solid particle number (SPN) emissions of motorcycles are usually higher than that of passenger cars. The L-category (e.g., mopeds, motorcycles) Euro 4 and 5 environmental steps were designed to reduce the emissions of particulate matter and ozone precursors such as nitrogen oxides and hydrocarbons. In this study the SPN emissions of one moped and eight motorcycles, all fulfilling the Euro 4 standards, were measured with a SPN measurement system employing a catalytic stripper to minimize volatile artefacts. Although the particulate matter mass emissions were &lt;1.5 mg/km for all vehicles tested, two motorcycles and the moped were close to the SPN limit for passenger cars (6 &times; 1011 particles/km with sizes larger than 23 nm) and four motorcycles exceeded the limit by a factor of up to four. The measurement repeatability was satisfactory (deviation from the mean 10%) and concentration differences between tailpipe and dilution tunnel were small, indicating that performing robust SPN measurements for regulatory control purposes is feasible. However, steady state tests with the moped showed major differences between the tailpipe and the dilution tunnel sampling points for sub-23 nm particles. Thus, the measurement procedures of particles for small displacement engine mopeds and motorcycles need to be better defined for a possible future introduction in regulations

Particulate emissions of euro 4 motorcycles and sampling considerations

The scientific literature indicates that solid particle number (SPN) emissions of motorcycles are usually higher than that of passenger cars. The L-category (e.g., mopeds, motorcycles) Euro 4 and 5 environmental steps were designed to reduce the emissions of particulate matter and ozone precursors such as nitrogen oxides and hydrocarbons. In this study the SPN emissions of one moped and eight motorcycles, all fulfilling the Euro 4 standards, were measured with a SPN measurement system employing a catalytic stripper to minimize volatile artefacts. Although the particulate matter mass emissions were <1.5 mg/km for all vehicles tested, two motorcycles and the moped were close to the SPN limit for passenger cars (6 × 1011 particles/km with sizes larger than 23 nm) and four motorcycles exceeded the limit by a factor of up to four. The measurement repeatability was satisfactory (deviation from the mean 10%) and concentration differences between tailpipe and dilution tunnel were small, indicating that performing robust SPN measurements for regulatory control purposes is feasible. However, steady state tests with the moped showed major differences between the tailpipe and the dilution tunnel sampling points for sub-23 nm particles. Thus, the measurement procedures of particles for small displacement engine mopeds and motorcycles need to be better defined for a possible future introduction in regulations.JRC.C.4-Sustainable Transpor

Effect of Extreme Temperatures and Driving Conditions on Gaseous Pollutants of a Euro 6d-Temp Gasoline Vehicle

Gaseous emissions of modern Euro 6d vehicles, when tested within real driving emissions (RDE) boundaries, are, in most cases, at low levels. There are concerns, though, about their emission performance when tested at or above the boundaries of ambient and driving conditions requirements of RDE regulations. In this study, a Euro 6d-Temp gasoline direct injection (GDI) vehicle with three-way catalyst and gasoline particulate filter was tested on the road and in a laboratory at temperatures ranging between −30 °C and 50 °C, with cycles simulating urban congested traffic, uphill driving while towing a trailer at 85% of the vehicle’s maximum payload, and dynamic driving. The vehicle respected the Euro 6 emission limits, even though they were not applicable to the specific cycles, which were outside of the RDE environmental and trip boundary conditions. Most of the emissions were produced during cold starts and at low ambient temperatures. Heavy traffic, dynamic driving, and high payload were found to increase emissions depending on the pollutant. Even though this car was one of the lowest emitting cars found in the literature, the proposed future Euro 7 limits will require a further decrease in cold start emissions in order to ensure low emission levels under most ambient and driving conditions, particularly in urban environments. Nevertheless, motorway emissions will also have to be controlled well

Transport-related airborne nanoparticles: Sources, different aerosol modes, and their toxicity

Nanoparticle emissions from transport are of considerable importance because of their dominance in terms of particle number concentration in most urban atmospheres. Nanoparticles may carry toxic substances, posing a serious threat to pedestrians, passengers and residents. The road sector has been studied intensively in both academia and industry and considerable knowledge has already been gathered. Shipping is also a significant source of nanoparticles both at the global and the European level and may be responsible for cardiopulmonary diseases and lung cancer at the global level, while ship emissions are known as one of the least regulated sources of pollutants. Aviation nanoparticle emissions have also received increasing attention in recent years because of the rapid growth of air transport volumes and the expected expansion to meet capacity needs for future years. Exhaust nanoparticle emissions from diesel rail transport are not very well known and only a few sources addressing actual emission rates are available. All modes of transport are sources of non-exhaust nanoparticle number emission associated with the tire, brake, and road/rail surface wear and tear. This paper provides a literature review to identify the different aerosol modes (i.e., primary, delayed primary, and secondary) from each transport source (road, shipping, aviation, rail), in both laboratory and field tests and to explore their toxicity relevance. The review focuses on nanoparticles (<100 nm) and investigates both exhaust and non-exhaust emissions. We present details on nanoparticles produced by transport sources in the urban environment and parameters that influence nanoparticle emissions. Also, we review the potential relationship between the different aerosol modes and their toxicity effects and point out some issues concerning nanoparticle collection for chemical and toxicity characterization. As regards the toxicity part, it is concluded that transport sources emit large number of nanoparticles which may pose a health risk. They can damage the respiratory tract and lungs, thus playing a crucial role in the physiology of pulmonary pathologies. These nanoparticles can also affect other organs, and the cardiovascular, nervous, and reproductive systems. The combination of oxidative stress, mitochondrial damage, inflammation, and activation of apoptosis, are the initiators of the systemic toxicity of nanoparticles, triggered by a unique combination of heavy metals and organic compounds present in combustion products.This work was funded by European Union’s Horizon 2020 Research and Innovation programme, under grant agreement № 954377.Peer reviewe