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JRC115979

EUR 29905 EN

PDF | ISBN 978-92-76-14123-5 | ISSN 1831-9424 | doi:10.2760/003337 | KJ-1A-29905-EN-N
Print | ISBN 978-92-76-14124-2 | ISSN 1018-5593 | doi:10.2760/214318 | KJ-1A-29905-EN-C
EPUB | ISBN 978-92-76-14314-7 | ISSN 1831-9424 | doi:10.2760/46252 | KJ-1A-29905-EN-E

Luxembourg: Publications Office of the European Union, 2019 Ispra: European Commission, 2019

© European Union, 2019

The reuse policy of the European Commission is implemented by the Commission Decision 2011/833/EU of 12 December 2011 on the reuse of Commission documents (OJ L 330, 14.12.2011, p. 39). Except otherwise noted, the reuse of this document is authorised under the Creative Commons Attribution 4.0 International (CC BY 4.0) licence (https://creativecommons.org/licenses/by/4.0/). This means that reuse is allowed provided appropriate credit is given and any changes are indicated. For any use or reproduction of photos or other material that is not owned by the EU, permission must be sought directly from the copyright holders.

All content © European Union, 2019

How to cite this report: Suarez-Bertoa, R., Astorga C., Franco V., Kregar Z., Valverde V., Clairotte M., Pavlovic J., Giechaskiel B. On-road vehicle emissions beyond RDE conditions 29905 EN, Publications Office of the European Union, Luxembourg, 2019, ISBN 978-92-76-14123-5, doi:10.2760/003337, JRC115979.

This is a re-edition of: Suarez-Bertoa, R., Astorga C., Franco V., Kregar Z., Valverde V., Clairotte M., Pavlovic J. and Giechaskiel B., On-road vehicle emissions beyond RDE conditions, EUR 29905 EN, Publications Office of the European Union, Luxembourg, 2019, ISBN 978-92-76-12392-7, doi:10.2760/779200, JRC115979.

JRC TECHNICAL REPORTS

On-road vehicle emissions beyond RDE conditions

Experimental assessment addressing EU Real-Driving Emission (RDE)

This publication is a Technical report by the Joint Research Centre (JRC), the European Commission’s science and knowledge service. It aims to provide evidence-based scientific support to the European policymaking process. The scientific output expressed does not imply a policy position of the European Commission. Neither the European Commission nor any person acting on behalf of the Commission is responsible for the use that might be made of this publication.

EU Science Hub

https://ec.europa.eu/jrc

JRC Mission

As the science and knowledge service of the European Commission, the Joint Research Centre’s mission is to support EU policies with independent evidence throughout the whole policy cycle.

Foreword

Directorate C Sustainable Transport Unit (unit C4) designed and carried out a testing campaign during 2017 and 2018 using tests outside Real-driving emissions (RDE) boundary conditions and experimental work in the context of the Administrative Arrangement ENV-070201-JRC.743134 entitled Real Driving emissions of new diesel vehicles.

This technical report is an assessment on real world performance and emission factors of some of the top selling diesel and gasoline cars models of the EU market. The document includes an evidence based assessment for policy making addressed to DG ENV. The report describes the evaluation on real world performance and the production of emission factors of representative top selling diesel and gasoline cars models of the EU market. This report also includes the data of the most relevant results regarding the behaviour of those cars when running beyond the so called "extended conditions", meaning cold ambient temperature (<-7°C), high altitude (>1300m), as well as high vehicle driving dynamics.

The experimental campaign was planned with a proactive and forward-looking frame. The STU has developed its capacity to anticipate future policy actions in relevant areas of vehicle pollutant emissions. Therefore, the output of the AA contains data on various powertrains (diesel, gasoline, natural gas and plug-in hybrid). It presents and discusses on road emissions of NOx, NO₂, CO, PN and CO₂ from twenty-one Euro 6b, or newer vehicles, including ten diesel (three of which certified to Euro 6d-TEMP), nine gasoline (direct injection (GDI) and port fuel injection (PFI), one of which is certified to Euro 6d-TEMP), one plug-in hybrid and one CNG vehicles.

Although RDE accounts for a large share of real-world driving, it excludes certain driving situations by setting boundary conditions (e.g., in relation to altitude, temperature or dynamic driving). The vehicles were investigated in different on-road scenarios and exploring the emissions taking place when vehicles were tested outside the RDE boundary conditions and compared to tests performed using RDE routes.

Acknowledgements

Authors would like to acknowledge the support and collaboration of (in alphabetical order) A. Bonamin, F. Buchet, M. Cadario, M. Carriero, G. Cotogno, F. Forloni, F. Forni, P. Le Lijour, D. Lesueur, F. Montigny, M. Otura-Garcia, V. Padovan, M. Sculati, and A. Zappia.

Authors

Suarez-Bertoa Ricardo, Astorga Covadonga, Franco Vicente, Kregar Zlatko Valverde, Victor, Clairotte Michael, Pavlovic Jelica, Giechaskiel Barouch.

Abstract

Passenger cars are an important source of air pollution, especially in urban areas. Recently, real-driving emissions (RDE) test procedures have been introduced in the EU aiming to evaluate nitrogen oxides (NOx) and particulate number (PN) emissions from passenger cars during on-road operation. Although RDE accounts for a large share of real-world driving, it excludes certain driving situations by setting boundary conditions (e.g., in relation to altitude, temperature or dynamic driving).

The present work investigates the on-road emissions of NOx, NO₂, CO, particle number (PN) and CO₂ from a fleet of twenty-one Euro 6b, 6c and 6d-TEMP vehicles, including diesel, gasoline (GDI and PFI) and compressed natural gas (CNG) vehicles. The vehicles were tested under different on-road driving conditions both inside and outside of RDE boundaries. These included ‘baseline’ tests within RDE conditions, but also testing in conditions beyond the RDE boundary conditions to investigate the performance of the emissions control devices in demanding situations.

Consistently, low average emission rates of PN and CO were measured from all diesel vehicles tested under most conditions. Moreover, the tested Euro 6d-TEMP and Euro 6c diesel vehicles met the NOx emission limits applicable to Euro 6d-TEMP diesel vehicles during RDE tests (168 mg/km). Some of the vehicles met this limit even outside the RDE boundaries. The Euro 6b GDI vehicle equipped with a gasoline particulate filter (GPF) presented PN emissions < 6×10¹¹ #/km. These results, in contrast with previous on-road measurements from earlier Euro 6 vehicles, indicate more efficient emission control technologies are currently being used in diesel and gasoline vehicles.

However, the results described in this report also raise some new concerns. In particular, the emissions of CO (measured during the regulated RDE test, but without an emission limit associated to it) or PN from PFI vehicles (presently not covered by the Euro 6 standard) showed elevated results in some occasions. Emissions of CO were up to 7.5 times higher when the more dynamic tests were conducted and the highest PN emissions were measured from a PFI gasoline vehicle during dynamic driving.

The work also investigates how NOx, CO, PN and CO₂ on-road emissions from three vehicles are impacted by sub-zero ambient temperatures and high altitudes. Two of the tested vehicles were Euro 6d-TEMP certified vehicles, one diesel and one gasoline, and one was a Euro 6b plug-in hybrid vehicle. The vehicles were studied during tests that do not fulfil the boundary conditions in terms of maximum altitude, altitude gain, and/or minimum temperature. The obtained emissions were compared to those obtained during tests performed along RDE routes.

The results indicate that cold ambient temperature and high altitude, outside the RDE boundary conditions, lead to higher NOx, CO and PN emissions compared to moderate conditions of temperature and altitude. Nonetheless, the two Euro 6d-TEMP vehicles tested in those extreme conditions yielded NOx emissions factors that fulfilled the Euro 6d-TEMP emission requirements.

Our work underlines the importance of a technology- and fuel-neutral approach to vehicle emission standards, whereby all vehicles must comply with the same emission limits for all pollutants.

1   Introduction

Air pollution remains the most important environmental cause of premature death in the EU as well as globally. Despite notable improvements during the last decades, poor air quality continues to cause over 400 000 premature deaths in the EU each year. Moreover, air quality present other health and environmental impacts which extend to acute and chronic respiratory, cardiovascular and other diseases and associated socio-economic costs. The European Clean Air Programme considers the high concentrations of particulate matter, nitrogen dioxide and ground-level ozone of most concern. Hence the strategic objectives are set accordingly based on an extensive evaluation and impact assessment [SWD, 2013]. It is furthermore noted that, for some air pollutants, EU air quality standards are less strict than the specific guideline values provided by World Health Organization [WHO, 2005]. To achieve compliance with the EU air quality standards and, in the long term, move towards those stated in the WHO guidelines, air pollutant emissions need to be reduced at local, national and transboundary levels.

Recent seasonal studies have shown that in some urban areas the highest levels of NOx, NH₃, CO and PM occur in the cold season [Hofman et al., 2016; Hama et al., 2017]. Those studies, as well as the recent report presented by the European Environment Agency [EEA, 2018], indicate that transport sector is among the main sources of NOx, CO, volatile organic compounds (VOCs), primary aerosols and secondary aerosol precursors [EEA, 2018; Gordon et al., 2014; Platt et al., 2017; Suarez-Bertoa et al., 2015; Link et al.,2017; Anenberg et al, 2017]. These pollutants play key roles in the formation of tropospheric ozone (O₃) and secondary aerosols that impair air quality. Winter season, in particular, is associated with high pollution episodes [Custódio et al. 2016; Wang et al. 2017].

The successive revisions of the EU type approval legislation aimed at reducing emissions from cars through the introduction of the respective EURO standards (1 to 6). The latest focus was on PM and NOx. Already in 2011 it was acknowledged that cars could emit more than the legal standards under real-driving conditions, thereby confirming earlier speculations about a growing problem in this field. The difference in emissions could be anywhere between 2 to 20 times the legal emission limits for Euro 5 diesel vehicles. The Volkswagen case has brought this matter to the forefront of the political agenda both in the EU and in the Member States, and has undermined consumer confidence in the car industry and the regulators.

Although RDE accounts for a large share of real world situations there are several boundary conditions that were introduced to allow the test to be representative of European real driving. These boundary conditions include: vehicle dynamics, positive altitude gain, speed share of operations, ambient temperature, among others. Moreover, the RDE requires not-to-exceed limits (NTE) only for NOx and solid particle number (PN) emissions. As for laboratory type-approval procedure, in RDE the PN limit only applies for diesel (DV) and gasoline direct injection vehicles (GDI). Moreover, in the laboratory type-approval procedure there is a limit for CO. Therefore, a series of situations, such as on-road CO emissions, PN emissions from port fuel injection (PFI) gasoline vehicles, off-boundary condition testing, are not covered by the current RDE regulation.

1.1 Scope of the study

The overall objective of this work is to gain targeted independent evidence and assessments about the sector's progress in reducing real-driving exhaust emission levels of air pollutants from new vehicles reaching the EU market.

Efforts of the experimental work focused on testing and assessing some of the most popular new models on the European market, as these are assumed to account for the largest fraction of the total emissions, especially in urban areas. This approach provides further technical input to vehicle emissions policy concerns by the European Commission, particularly in relation to considerations towards setting up a voluntary system for identification of low emission vehicles.

Another objective was to provide a better indication of the current state of real-driving emissions to the Commission and the public at large. The JRC has already been performing real world testing of light duty vehicles for many years now, as documented in several publications [Weiss et al., 2011; 2012; 2013; Giechaskiel et al., 2014]. JRC has also been fully involved in the preparation of the RDE [2016/646; 2017/1151; 2018/1832] acts, supporting discussions with scientific evidence throughout the whole process and has been actively involved in setting new emission factors for use in air quality modelling through the ERMES group. The specific objectives of this study were as follows:

Box 1. Objectives of the experimental program.

Objective 1 - Assess real world performance of some of the best-selling models on the EU market.

This part focussed on the newest and most popular diesel and gasoline models sold, ranked by their most recent total sales in the EU. Recently type-approved vehicles (presumably engineered with RDE provisions in mind) were prioritized. It is necessary to test the most recent vehicles sold, because in a normal vehicle life cycle, it is expected that these will be on the market for longer. Also, a few independent studies [Franco et al., 2014, Kadijk et al., 2016] that have investigated vehicle exhaust emissions have focused on the higher and more expensive end of the market. Therefore, a better coverage of lower vehicle market segments was desirable.

Objective 2 - Contribute to production of appropriate emission factors for these vehicles

Policy makers and stakeholders that deal with exceedances of air pollutants concentrations need to know the emission performance of most popular vehicles with sufficient detail. Up-to-date emission factors must be used in emission and air quality modelling in order to evaluate the effectiveness of newer diesel technology (driven by the phase-in of mandatory RDE not-to-exceed limits). The data resulting from the vehicle testing be made available to the broad community of emission modelers, specifically to the ERMES network.

Following the aforementioned objectives, the present work investigates the emissions of NOx, NO₂, CO, PN and CO₂ from a fleet of 21 Euro 6b+ vehicles, including diesel, gasoline (GDI and PFI) and CNG vehicles, under different driving conditions. Emissions of the vehicles tested during RDE compliant tests, which act as base line, were compared to emissions obtained during tests that do not fulfil the boundary conditions in terms of dynamicity (excessively dynamic driving), share of operation (too long urban and/or motorway shares), altitude gain (excessive altitude gain), among others. Table 1 summarizes a not exhaustive list of these requirements and boundary conditions for a test to be RDE compliant.

The work does not only shed light on the current state of vehicle emissions under different real world conditions but it is an important source for emission factors. The obtained emission factors will allow updating current vehicle emissions inventories providing real world emissions of pollutants that are not included in on-road regulation at the moment (CO and PN from PFI). Moreover, it presents some of the first results of vehicles type-approved under the most stringent emission standards at the moment (Euro 6d-TEMP) investigated under different real-world driving situations.

The RDE procedure requires the measurement of NOx and PN for all passenger cars (with the exception of PN from non-direct injection gasoline vehicles, i.e., port fuel injection – PFI) at ambient temperature as low as -2°C for vehicles type-approved as Euro 6d-TEMP vehicles and down to -7°C for those type approved after 1 September 2019. The current laboratory-based test at cold temperature (-7 ±3°C) only requires the measurement of total hydrocarbons (THC) and CO emissions from gasoline vehicles (see Figure 1), with a limit for the emissions which are more than 15 times higher than those allowed during Type 1 test performed at 23 ±5 °C.

Figure 1. Cold ambient laboratory test for light-duty vehicles. Global state of play.

* CO₂ is analysed and results used for the determination of the vehicle fuel economy. Cold temperature standards apply for CO and NMHC emissions.

Therefore, it is also in the scope of this study to investigate how sub-zero ambient temperatures and high altitudes impact the on-road emissions of NOx, CO, PN and CO₂ from two Euro 6d-TEMP certified vehicles, one diesel (DV8) one gasoline (GV9), and one Euro 6b plug-in hybrid vehicle (PHEV).

The vehicles were studied during tests that do not fulfil the boundary conditions in terms of maximum altitude (one route reaches >2000 m.a.s.l.), altitude gain (altitude gain >1200m/100km), and/or minimum temperature (< -2°C) and the emissions were compared to those obtained during tests performed fulling most of the requiring RDE regulation. These tests acted as base line. Emissions during the urban section of the on-road tests as well as during cold start were also evaluated as they could have a higher impact on urban air quality.

Box 2. Supporting material and information.

The present report was based on the data of the most relevant results concerning the behaviour of the studied cars when running beyond the so called "extended conditions", including altitude gain (altitude gain >1200m/100km), as well as high vehicle driving dynamics, presented in the following peer reviewed article:

Suarez-Bertoa Ricardo, Valverde Victor, Clairotte Michael, Pavlovic Jelica, Giechaskiel Barouch, Franco Vicente, Kregar Zlatko, and Astorga Covadonga. On-road emissions of passenger cars beyond the boundary conditions of the Real-Driving Emissions test. Environmental Research. 2019. 176, 108572.

Table 1. Some of the requirements and boundary conditions for a test to be RDE compliant.

Altitude (m.a.s.l.) | Moderate conditions | 0 – 700
Extended conditions | 700 – 1300
Ambient temperature | Moderate conditions | 0 – 30 °C
Extended conditions | −7 – 0 °C and 30 – 35 °C
Cumulative positive elevation gain |  | 1200 m every 100 km
Altitude difference between start and finish |  | <100 m
Dynamics | Upper limits | 95th percentile of the multiplication of the instant speed and positive acceleration signals as defined in Appendix 7a, Section 4 of RDE 3.
Lower limits | Relates to the relative positive acceleration as defined in Appendix 7a, Section 4 of RDE 3.
Maximum speed |  | 145 km/h (up to 160 km/h for <3% of motorway driving time).
Payload |  | Maximum 90% of the maximum vehicle weight (including the mass of the driver and measurement equipment).
Stop percentage |  | Between 6% and 30% of the urban driving time.
Speed | Average urban speed | 15 – 40 km/h
| above 100 km/h for at least 5 minutes.
Distance |  | Urban >16 km; Rural >16 km; Motorway >16 km
Trip Composition |  | Urban 29 – 44% of the total distance; Rural 23 – 43% of the total distance; Motorway 23 – 43% of the total distance.
Total Trip Duration |  | 90 – 120 minutes
Use of auxiliary systems |  | Operated as in real life use (air conditioning, etc.).

2   Research methodology: Results and discussion

Two experimental campaigns were conducted by the Sustainable Transport Unit of the European Commission Joint Research Centre (EC-JRC) between March 2017 and December 2018 aiming at investigating the impact that driving style, shares of operation, cold ambient temperature and high altitude could have on vehicle emissions during real life driving.

In order to investigate the impact of driving style and/or shares of operation, emissions of NOx, NO₂, CO, PN and CO₂ from 19 Euro 6 vehicles (see Table 3 and Table 4 for main characteristics and for further details including brand and model) were comprehensively studied under different driving conditions.

The fleet comprised, 8 gasolines (7 Euro 6b and 1 Euro 6c), 10 diesels (6 Euro 6b, 1 Euro 6c and 3 Euro 6d-TEMP) and 1 Euro 6b CNG light commercial vehicle (hereinafter CNG-LCV). The vehicles were tested during RDE-compliant tests, which act as baseline, and also during tests that do not fulfil RDE boundary conditions in terms of dynamicity (excessive dynamic driving), share of operation (urban and/or motorway shares above RDE requirements), altitude gain (excessive altitude gain), among others. The vehicles were tested with PEMS over four different pre-defined routes in the Italian region of Lombardy: two fully RDE-compliant (route identifiers RDE-1 and RDE-2) and 2 non-RDE compliant (City-Motorway and Hill) (see Table 2).

To investigate the impact of cold ambient temperature and high altitude, on the NOx, CO, PN and CO₂ emissions from one Euro 6d-TEMP gasoline (GV9), one Euro 6d-TEMP diesel (DV8) and one Euro 6b gasoline-PHEV were comprehensively studied. The vehicles were tested during: i) Two RDE-compliant routes (route identifiers RDE-1 and RDE-2; hereinafter RDE-routes), which act as baseline, ii) one on-road test that does not fulfill RDE boundary conditions in terms of minimum temperature (< -2°C) and is at the high end of the maximum altitude boundary (Max. altitude 1300 m.a.s.l.) (hereinafter Alpine-1) and iii) one on-road test that do not fulfill RDE boundary conditions in terms of maximum altitude (one route reaches >2000 m.a.s.l.), altitude gain (altitude gain >1200m/100km), and minimum temperature (< -2°C) (hereinafter Alpine-2). Table 2 summarizes the main features of the tests performed.

The vehicles used in this study were selected to be a representative sample of the European market for new vehicles. The tested fleet included some of the best-selling models from different manufacturers across vehicle segments and engine sizes. The vehicles were equipped with the usual exhaust after-treatment technologies in the EU for new cars sold between 2016 and 2018. Gasoline vehicles used either port fuel injection (PFI) or direct injection (GDI) technology. One gasoline vehicle (GV8) was equipped with a gasoline particulate filter (GPF). All diesel vehicles were equipped with an exhaust gas recirculation (EGR) system and either a lean NOx trap (LNT), selective catalytic reduction (SCR) or both (DV9) to control NOx emissions. One diesel vehicle (DV10, type-approved to Euro 6d-TEMP) was equipped with a dual LNT and a passive SCR (not requiring urea solution refills).

Table 2. Trips characteristics. Bold indicates that the value is outside RDE boundary conditions.

| RDE compliant routes | Non-RDE compliant routes
| RDE-A | RDE-B | RDE-A-Dyn. | RDE-B-Dyn. | City-MW | Hill | Alpine-1 | Alpine-2
Trip distance (km) | 79 | 94 | 79 | 94 | 139 | 61 | 87 | 84
Av. trip duration (min) | 98 | 112 | 94 | 104 | 136 | 106 | 108 | 91
Ambient Temperature (°C) | 11–27 | 7–32 | 5–30 | 9–33 | 8–30 | 5–31 | -5 | -6 – -7
Av. Urban distance (km) | 32 | 37 | 31 | 34 | 44 | 61 | 36 | 36
Av. Rural distance (km) | 25 | 27 | 25 | 28 | 18 | - | 24 | 22
Av. MW distance (km) | 22 | 30 | 23 | 32 | 80 | - | 27 | 25
Urban av. Speed (km/h) | 29 | 29 | 29 | 31 | 31 | 34 | 29 | 37
Av.Urban 95th v*a (m²/s³) | 13 | 13 | 20 | 20 | 10 | 9 | 8 | 11
Av. Rural 95th v*a (m²/s³) | 19 | 17 | 29 | 30 | 19 | - | 16 | 19
Av. MW 95th v*a (m²/s³) | 19 | 21 | 29 | 30 | 18 | - | 21 | 17
Cumulative positive gain (m/100km) | 760 | 820 | 760 | 820 | 440 | 1830 | 1015 | 1687
Max trip altitude (m) | 300 | 415 | 300 | 415 | 295 | 1088 | 1380 | 2040

Table 3. Vehicle specifications. Gasoline vehicles (GV), plug-in hybrid vehicle (PHEV) and compressed natural gas light commercial vehicle (CNG-LCV).

Code | Brand | Model | Fuel | Inj. | Emission Control system | Reg. Year | Euro standard | Engine Capty. (cm³) | Power (kW)
GV1 | Fiat | Panda | Gasoline | PFI | TWC | 2016 | Euro 6b | 1242 | 51
GV2 | Renault | Twingo | Gasoline | PFI | TWC | 2017 | Euro 6b | 999 | 51
GV3 | Audi | A1 | Gasoline | DI | TWC | 2016 | Euro 6b | 999 | 70
GV4 | Opel | Astra | Gasoline | DI | TWC | 2017 | Euro 6b | 999 | 77
GV5 | VW | Golf BlueMotion | Gasoline | DI | TWC | 2017 | Euro 6c | 1498 | 96
GV6 | Lancia | Ypsilon | Gasoline | PFI | TWC | 2016 | Euro 6b | 875 | 63
GV7 | Renault | Clio | Gasoline | DI | TWC | 2016 | Euro 6b | 1197 | 87
GV8 | VW | Tiguan | Gasoline | DI | TWC+GPF | 2018 | Euro 6b | 1395 | 110
GV9 | Citroën | C3 | Gasoline | PFI | TWC | 2018 | Euro 6d-TEMP | 1199 | 61
PHEV | Mitsubishi | Outlander | Gasoline | PFI | TWC | 2015 | Euro 6b | 1968 | 149
CNG-LCV | Fiat | Ducato | CNG | PFI | TWC | 2018 | Euro 6b | 2999 | 100

Table 4. Diesel vehicles (DV) specifications.

Code | Brand | Model | Fuel | Inj. | Emission Control system | Reg. Year | Euro standard | Engine Capty. (cm³) | Power (kW)
DV1 | Fiat | 500X | Diesel | DI | DOC+EGR+DPF+LNT | 2016 | Euro 6b | 1956 | 103
DV2 | Peugeot | Partner | Diesel | DI | DOC+EGR+DPF+SCR | 2017 | Euro 6b | 1560 | 73
DV3 | Kia | Sportage | Diesel | DI | DOC+EGR+LNT+DPF | 2017 | Euro 6b | 1685 | 85
DV4 | VW | Golf BlueMotion | Diesel | DI | DOC+EGR+LNT+DPF | 2015 | Euro 6b | 1968 | 110
DV5 | BMW | 530d - 5 series G30 | Diesel | DI | DOC+ EGR+SCR+LNT+DPF | 2017 | Euro 6b | 2993 | 195
DV6 | Mercedes-Benz | C220d | Diesel | DI | DOC+ EGR+DPF+SCR | 2017 | Euro 6b | 2143 | 125
DV7 | Škoda | Superb | Diesel | DI | DOC+ EGR+DPF+SCR | 2017 | Euro 6c | 1968 | 110
DV8 | Peugeot | 308 | Diesel | DI | DOC+ EGR+DPF+SCR | 2018 | Euro 6d-TEMP | 1499 | 96
DV9 | Volvo | XC40 | Diesel | DI | DOC+EGR+ DPF+LNT+SCR | 2018 | Euro 6d-TEMP | 1969 | 140
DV10 | Ford | Focus | Diesel | DI | DOC+EGR+LNT+DPF+LNT+pSCR | 2018 | Euro 6d-TEMP | 1499 | 88

2.1 On-road emissions impact of driving dynamics and shares of operations

2.1.1 NOx emissions

The emissions factors indicated as RDE and Dynamic are the mean of the emissions obtained using routes RDE-1 and RDE-2 for the RDE compliant tests and the dynamic tests, respectively. Figure 2 illustrates NOx median emissions factors from diesel and gasoline vehicles obtained during the tests performed using the different routes and driving styles. Table 5 summarizes the NOx emission factors for each individual vehicle.

Figure 2. NOx median emissions factors from diesel (left plot) and gasoline (right plot) vehicles

Most gasoline vehicles complied with the NOx Euro 6d-TEMP on-road NTE (i.e., 60 mg/km multiplied by a conformity factor of 2.1) with the exception of GV8 during one of the dynamic tests (205 mg/km), the GV4 during the Hill route (288 mg/km). In addition, NOx emissions higher than the Euro 6d limits (60 mg/km multiplied by a conformity factor 1.43) were measured from GV7 during the Dynamic test (92 mg/km) and GV4 during RDE and Dynamic (91 and 93 mg/km respectively).

NOx median emissions factors from the diesel fleet (DV1 – DV10) were one order of magnitude higher than those of the gasoline fleet, and varied from ~92 mg/km, during the Hill and RDE compliant tests respectively, to 349 mg/km during the Dynamic tests. Individual average emission factors ranged from 9 mg/km (DV7) during the RDE test to 1011 mg/km (DV3) during the dynamic tests. The Euro 6b diesel vehicles DV1 – DV4 (type approved under the NEDC) tested under RDE compliant tests presented NOx emissions from similar (DV4) to up to 4 times higher than the diesel’s RDE Euro 6d- TEMP (i.e., 80 mg/km multiplied by a conformity factor of 2.1) and 1.4 to 6 times higher than the RDE Euro 6d standard (i.e., 80 mg/km multiplied by a conformity factor of 1.43). Vehicle DV4 met the Euro 6d-TEMP tailpipe emissions requirements but it fell short of meeting Euro 6d. Vehicles DV5 and DV6 met the more stringent RDE Euro 6d. The elevated NOx emissions from Euro 6b vehicles could be explained by the after-treatment strategies and low efficiency of the catalytic systems used in those vehicles to reduce the emissions of NOx, namely SCR or LNT [Ko et al., 2017; O'Driscoll et al., 2016; 2018; Suarez-Bertoa et al., 2015b; 2016; 2017; Yang et al., 2015].

Table 5. Emission factors of NOx (mg/km) during the RDE, Dynamic (Dyn.), City-Motorway (City-MW) and Hill tests. The emissions factors presented in the columns RDE and Dyn. are the average of the emissions obtained along the two different routes (RDE-1 and RDE-2) tested using these two different driving dynamics (RDE and Dynamic)

| GV1 | GV2 | GV3 | GV4 | GV5 | GV6 | GV7 | GV8 | CNG-LCV
RDE | 6 | 15 | 39 | 91 | 11 | 21 | 46 | 20 | 164
Dyn. | 13 | 12 | 33 | 93 | 20 | 16 | 92 | 115 | 956
City-MW | 9 | 11 | 21 | 62 | 5 | - | 18 | 16 | 242
Hill | 8 | 19 | 56 | 288 | 10 | - | 25 | 18 | 515

| DV1 | DV2 | DV3 | DV4 | DV5 | DV6 | DV7 | DV8 | DV9 | DV10
RDE | 476 | 552 | 569 | 147 | 33 | 78 | 13 | 60 | 57 | 119
Dyn. | 702 | 784 | 1005 | 645 | 85 | 300 | 39 | 188 | 319 | 338
City-MW | - | 799 | 673 | 179 | - | 141 | 13 | 19 | 34 | 89
Hill | 639 | 405 | 641 | 203 | 59 | 93 | 31 | 72 | 51 | -

Vehicles DV8, DV9 and DV10 were type approved to the Euro 6 d-TEMP standard using WLTP and RDE tests. On the other hand, an RDE test was not required for vehicles DV5, DV6 and DV7 at the time of type approval. Nonetheless, together with the Euro 6d-TEMP vehicles (DV8 – DV10), they met the Euro 6d NOx tailpipe emissions requirements during the RDE, City and Hill tests. Only during the Dynamic tests, the NOx emission factors were higher than Euro 6 limits. Vehicles DV5 (during RDE-1-Dyn) and DV8 (during RDE-2-Dyn) were below the Euro 6d NOx requirements. Moreover, DV7 yielded very low emissions for this test (39 mg/km). This indicates that, although there is room for improvement, substantial progress has been made on NOx emission control in the more recent and that high reduction efficiency of NOx is often maintained beyond the dynamic boundaries of RDE. Vehicles DV7, DV8 and DV9 achieved lower NOx emissions compared to the Euro 6b diesel vehicles by using more advanced and complex catalytic systems (e.g., EGR + LNT + SCR, EGR + dual-LNT) and, possibly, a higher urea solution dosage in the SCR.

NOx emissions from the CNG-LCV were the highest recorded among the positive ignition vehicles (see Table 5). They ranged from 164 mg/km during the RDE route to 956 mg/km during the Dynamic routes, which is 9 times higher than the worst performing gasoline vehicle. It should be noted that this vehicle (CNG-LCV) was a light commercial vehicle whereas the other tested vehicles were passenger cars. Surprisingly, NOx emissions from the CNG-LCV were comparable to or higher than most of the diesel vehicles measured in this study. These high NOx emissions may be linked to lean engine operation.

2.1.2 NO₂ emissions

Before the introduction of DPF and SCR systems, NOx in diesel exhaust was usually composed of >90% NO. However, to decrease soot oxidation temperatures for the DPF regeneration and since equimolar amounts of NO and NO₂ increase the reaction rate with NH3 on the SCR, NO is oxidised to NO₂ on the DOC [Guan et al., 2014].

NOx emissions from the spark ignition vehicles tested were mainly composed of NO. Median NO₂ emissions from gasoline cars were very low (1 - 2 mg/km during all the tested routes with a maximum of 12 mg/km). On the other hand, median NO₂ emissions from diesel vehicles ranged from 23 to 94 mg/km, during the RDE and Dynamic routes respectively. Vehicles DV7 and DV8 emitted less than 5% of NOx as NO₂. Vehicles DV9 and DV10 had NO₂/NOx ratios (0.2) similar to those from Euro 6b vehicles.

Figure 3 illustrates NO₂ median emissions factors from diesel and gasoline vehicles obtained during the tests performed using the different routes and driving styles. Table 6 summarizes the NO₂ emission factors for each individual vehicle.

Figure 3. NO₂ median emissions factors from diesel (left plot) and gasoline (right plot) vehicles

The higher ratio of NO₂ emissions in the exhaust may have important effects on the urban atmospheric chemistry, and consequently on air quality. The EEA has recently reported that, following an increase of NO₂ emissions from diesel vehicles at the expense of NO, ground level ozone (O3) concentrations have increased in several air quality measurement stations monitoring pollution from traffic in the EU [EEA, 2018].

Table 6. Emission factors of NO₂ (mg/km) during the RDE, Dynamic (Dyn.), City-Motorway (City-MW) and Hill tests. The emissions factors presented in the columns RDE and Dyn. are the average of the emissions obtained along the two different routes (RDE-1 and RDE-2) tested using these two different driving dynamics (RDE and Dynamic).

| GV1 | GV2 | GV3 | GV4 | GV5 | GV6 | GV7 | GV8 | CNG-LCV
RDE | 0 | 3 | 1 | 2 | 1 | 0 | 1 | 2 | 15
Dyn. | 0 | 3 | 0 | 3 | 2 | 0 | 2 | 7 | 33
City-MW | 0 | 3 | 0 | 2 | 1 | - | - | 2 | 16
Hill | 0 | 3 | 3 | 2 | 1 | - | - | 3 | 21

| DV1 | DV2 | DV3 | DV4 | DV5 | DV6 | DV7 | DV8 | DV9 | DV10
RDE | 131 | 124 | 127 | 42 | 7 | 22 | 1 | 6 | 13 | 27
Dyn. | 176 | 125 | 190 | 157 | 10 | 104 | 2 | 14 | 40 | 110
City-MW | - | 207 | 139 | 38 | - | 67 | 2 | 0 | 0 | 16
Hill | 236 | 97 | 113 | 53 | 16 | 38 | 1 | 0 | 1 | -

2.1.3 PN emissions

Figure 4 illustrates PN median emissions factors from diesel and gasoline vehicles obtained during the tests performed using the different routes and driving styles. Table 7 summarizes the PN emission factors for each individual vehicle.

PN emissions from diesel vehicles were below Euro 6 limits (6×10¹¹ #/km) under all the studied conditions for all the studied vehicles even without using the applicable conformity factor of 1.5 for PN. PN median emissions ranged from 5×10⁹ #/km to 5×10¹⁰ #/km. There was no significant difference on PN emissions for the different routes used (see Figure 4). Although below Euro 6 limits, DV6 presented the highest PN emissions among the diesel vehicles (3.4-6.4 ×10¹¹ #/km), indicating lower filtration efficiency than the other tested vehicles. The measured PN emissions indicate an overall good performance of DPFs during real-world operation.

Figure 4. PN median emissions factors from diesel (left plot) and gasoline (right plot) vehicles

Table 7. Emission factors of PN (×10¹¹ #/km) during the RDE, Dynamic (Dyn.), City-Motorway (City-MW) and Hill tests. The emissions factors presented in the columns RDE and Dyn. are the average of the emissions obtained along the two different routes (RDE-1 and RDE-2) tested using these two different driving dynamics (RDE and Dynamic).

| GV1 | GV2 | GV3 | GV4 | GV5 | GV6 | GV7 | GV8 | CNG-LCV
RDE | 6 | 2 | 12 | 24 | 0.9 | 21 | 31 | 0.2 | 6
Dyn. | 11 | 4.5 | 28 | 34 | 1.2 | 104 | 62 | 0.3 | -
City-MW | 2.6 | 1.7 | 8.9 | 21 | 1.0 | - | 18 | 0.1 | -
Hill | 10 | 5.1 | 19 | 27 | 1.0 | - | 19 | 0.1 | -

| DV1 | DV2 | DV3 | DV4 | DV5 | DV6 | DV7 | DV8 | DV9 | DV10
RDE | - | - | 0.03 | - | 0.17 | 5.0 | 0.06 | 0.7 | 0.02 | 0.03
Dyn. | - | - | 0.01 | - | 2 | 6.1 | 0.20 | 0.7 | 0.06 | 0.07
City-MW | - | - | <0.01 | - | - | 3.4 | 0.30 | 0.6 | <0.01 | 0.01
Hill | - | - | 0.04 | - | 0.15 | 6.4 | 0.03 | 0.5 | 0.02 | -

Missing emission factors are due to instrument failure or instrument unavailability in case of stand-alone system.

PN emissions from gasoline vehicles were up to three orders of magnitude higher than those obtained from diesel vehicles. Median PN emissions from gasoline vehicles varied from 3×10¹¹ #/km to 2×10¹² #/km. They are below the laboratory PN limit for GDIs until 2017 (6×10¹² #/km), even without any additional margin. PN emissions from GDIs are higher due to the limited time available for fuel and air to be thoroughly mixed in the combustion chamber; these emissions increase during high-speed and sudden acceleration events due to rich air/fuel ratios [Überall et al., 2015; Yinhui et al., 2016]. On the other hand, PN emissions from PFI spark ignition vehicles are commonly linked to enrichment of the air-fuel mixture during cold start engine operations and accelerations. Although most of the GDIs studied here resulted in higher PN emissions than the PFIs, PN emissions from the PFIs exceed in some occasions the PN limits for diesel and GDI vehicles. High emissions of PFIs especially at dynamic cycles is not new [Giechaskiel et al., 2015; Suarez-Bertoa and Astorga, 2018].

The highest PN emissions were recorded for vehicle GV6, a PFI gasoline car, which not only exhibited very high PN emissions during the cold-start phase, but also across all trip sections. Emissions ranged from 2×10¹² #/km during the RDE routes to 1×10¹³ #/km during the dynamic routes. The lowest PN emissions resulted from vehicle GV8 (1×10¹⁰ – 3×10¹⁰ #/km), a GDI vehicle equipped with a gasoline particle filter (GPF). Although this was the only gasoline vehicle equipped with a GPF, the consistency of the results with those from previous studies indicate that GDIs equipped with a GPF consistently achieve much lower PN emissions than those without the GPF [Joshi and Johnson, 2018]. It needs to be seen if future GPFs will be able to reach the emission levels of efficient DPFs (one order of magnitude lower).

PN median emissions were unsurprisingly higher – 2 times– during the dynamic routes (2×10¹² #/km) than during the RDE routes (1×10¹² #/km). More dynamicity means more accelerations episodes, which in turn results in richer air/fuel ratios, hence in higher PN emissions. PN median emissions were 3.5 times lower during the City-Motorway route than during the RDE ones. Excluding GV6 from the analysis (as it was not tested along this route), the PN median emissions are 2.4 times lower during the City-Motorway route than during the RDE. In any case, as illustrated in Figure 4, there were no significant differences on PN emissions for different routes. PFIs though had tendency for higher emissions during the Hill route.

Due to an instrument failure, PN emissions from the CNG-LCV vehicle were only measured during the RDE tests. PN emissions were as high as those recorded from GDI vehicles reaching 1×10¹² #/km during the RDE-1 route. PN average emission factor during the RDE routes was 6×10¹¹ #/km. It should be noted that the specific vehicle had <3000km during the on road testing, so the contribution of fresh lubricant could be significant.

2.1.4 CO emissions

Figure 5 illustrates CO median emissions factors from diesel and gasoline vehicles obtained during the tests performed using the different routes and driving styles. Table 8 summarizes the CO emission factors for each individual vehicle.

CO emissions from diesel vehicles were below Euro 6 limits (500 mg/km) for all the studied vehicles and under all the studied conditions. Median CO emissions ranged from 20 and 41 mg/km. There was no significant difference on CO emissions for the different routes used (see Figure 5). The measured CO emissions indicate good performance of diesel oxidation catalysts (DOCs) during real-world operation.

Figure 5. CO median emissions factors from diesel (left plot) and gasoline (right plot) vehicles

CO Euro 6 emissions limit for gasoline light-duty vehicles is 1000 mg/km. CO median emissions from gasoline vehicles were one to two orders of magnitude higher than those obtained from diesel vehicles. Median CO emissions from gasoline vehicles ranged from 167 mg/km during the Hill test to 2850 mg/km during the dynamic test (see Figure 5). CO median emissions from gasoline emissions during dynamic tests were more than five times higher than those obtained during the RDE compliant tests.

Table 8. Emission factors of CO (mg/km) during the RDE, Dynamic (Dyn.), City-Motorway (City-MW) and Hill tests. The emissions factors presented in the columns RDE and Dyn. are the average of the emissions obtained along the two different routes (RDE-1 and RDE-2) tested using these two different driving dynamics (RDE and Dynamic)

| GV1 | GV2 | GV3 | GV4 | GV5 | GV6 | GV7 | GV8 | CNG-LCV
RDE | 681 | 2192 | 208 | 990 | 317 | 988 | 433 | 161 | 307
Dyn. | 2829 | 6234 | 1228 | 2577 | 864 | 7551 | 3303 | 2737 | 208
City-MW | 370 | 2234 | 455 | 930 | 108 | - | 307 | 181 | 440
Hill | 1046 | 450 | 167 | 199 | 115 | - | 127 | 149 | 317

| DV1 | DV2 | DV3 | DV4 | DV5 | DV6 | DV7 | DV8 | DV9 | DV10
RDE | 334 | 25 | 25 | 5 | 35 | 13 | 20 | 20 | 4 | 35
Dyn. | 243 | 25 | 75 | 6 | 36 | 30 | 27 | 31 | 0 | 24
City-MW | - | 32 | 34 | 9 | - | 21 | 30 | 0 | 0 | 56
Hill | 205 | 129 | 103 | 4 | 57 | 4 | 65 | 25 | 0 | -

Very high CO emissions were recorded for most gasoline vehicles during Dynamic trips, reaching concerning levels of 6000-8600 mg/km (see in particular GV2 and GV6); approximately 8 times more compared to the non-dynamic driving. For some vehicles they were associated to motorway operation during dynamic tests as well as RDE compliant test. These may be a consequence of an emissions strategy (AES) aiming to protect the TWC from overheating, but also may be due to an undersized catalyst. Since engine-out emissions were not measured during the testing campaign, it was not possible to examine the behaviour of the catalyst during these emission events. Further investigations will be conducted in future testing campaigns.

Regardless of its large engine displacement and high laden mass, the CNG-LCV exhibited the lowest CO emissions of all the positive ignition vehicles during the Dynamic tests, 208 mg/km. Nonetheless, CO emissions for this vehicle during the City-Motorway test (440 mg/km), were in agreement with the median of the other vehicles tested during City-Motorway (416 mg/km).

2.1.5 CO₂ emissions

Figure 6 illustrates CO₂ median emissions factors from diesel and gasoline vehicles obtained during the tests performed using the different routes and driving styles. Table 9 summarizes the CO₂ emission factors for each individual vehicle.

Median CO₂ emissions from diesel vehicles were slightly higher than median CO₂ emissions from the gasoline vehicles, contrary to normal expectation. Nonetheless, the vehicles tested presented in this study included several relatively small and lighter vehicles equipped with relatively small gasoline engines with average engine displacement of ~1150 cc and average power of ~75 kW. On the other hand, the average engine displacement and power of the diesel vehicles tested were ~1900 cc and ~112 kW. In addition, 5 out of 8 gasoline vehicles tested were GDIs, which are generally more efficient than PFIs.

Median CO₂ emissions increased for Dynamic trips in relation to RDE-compliant trip (+7% and +6% for gasoline and diesel, respectively). The highest impact of dynamic driving was measured for the CNG vehicle (+16%) which was also the heaviest vehicle. The City-Motorway driving resulted in lower CO₂ emissions compared to the RDE-compliant routes (-6% for both gasoline and diesel vehicles). The most energy-demanding route for diesel vehicles was the Hill route which on average resulted in 10% higher CO₂ emissions. In particular, this route was the most demanding for vehicles DV5 and DV6 (25% and 29% increase in CO₂ emissions, respectively). For gasoline vehicles, the Hill route exhibited 6% higher CO₂ emissions (average of all vehicles), with some gasolines vehicles (GV1 and GV5) achieving lower CO₂ emissions compared to RDE-compliant trips. It should be noticed that the Hill route begins and ends at the same point. Therefore, CO₂ emissions are the combination of and up-hill (Max. altitude ~1100m.a.s.l.) and downhill driving (Min. altitude ~200m.a.s.l.).

Figure 6. CO₂ median emissions factors from diesel (left plot) and gasoline (right plot) vehicles

Table 9. Emission factors of CO₂ (g/km) during the RDE, Dynamic (Dyn.), City-Motorway (City-MW) and Hill tests. The emissions factors presented in the columns RDE and Dyn. are the average of the emissions obtained along the two different routes (RDE-1 and RDE-2) tested using these two different driving dynamics (RDE and Dynamic).

| GV1 | GV2 | GV3 | GV4 | GV5 | GV6 | GV7 | GV8 | CNG-LCV
RDE | 155 | 156 | 129 | 140 | 154 | 201 | 166 | 172 | 243
Dyn. | 167 | 152 | 149 | 164 | 168 | 215 | 180 | 184 | 282
City-MW | 163 | 135 | 137 | 132 | 140 | - | 154 | 158 | 251
Hill | 140 | 166 | 156 | 167 | 142 | - | 186 | 182 | 268

| DV1 | DV2 | DV3 | DV4 | DV5 | DV6 | DV7 | DV8 | DV9 | DV10
RDE | 188 | 139 | 155 | 158 | 156 | 150 | 152 | 139 | 188 | 169
Dyn. | 203 | 154 | 165 | 173 | 177 | 162 | 153 | 150 | 209 | 162
City-MW | - | 145 | 158 | 152 | - | 137 | 135 | 131 | 171 | 151
Hill | 381 | 155 | 148 | 173 | 194 | 197 | 162 | 140 | 202 | -

2.2 On-road emissions impact of sub-zero ambient temperatures and high altitude

Table 10, Table 11 and Table 12 summarize NOx, PN, CO and CO₂ emissions factors from the DV8, the GV9 and the PHEV obtained for the complete tests, the subsections urban, rural and motorway of the tests performed using the four different routes (RDE-1, RDE-2, Alpine-1 and Alpine-2).

2.2.1 Emissions from a Euro 6d-TEMP diesel vehicle

Criteria emissions (CO, NOx and PN) from the DV8 were higher at colder temperatures during on-road tests (Table 10). NOx raw emissions were always below Euro 6d-TEMP on-road emission requirement (80 mg/km + 2.1 conformity factor). The highest NOx emissions factors (113 mg/km) were obtained during Alpine-2, which was the most demanding test in terms of road grade, altitude and cold ambient temperature.

NOx emissions from the DV8 during the complete Alpine tests were 72 mg/km for Alpine-1 and 113 mg/km Alpine-2, up to 2 times higher than those measured during the RDE compliant routes (51 mg/km), performed at 24°C.

NOx emission factors in the urban section (~36 km long for all four routes) were always higher than those obtained during the urban and motorway sections and ranged from 67 mg/km in the RDE-routes to 169 mg/km in the Alpine-2 (see Table 10). NOx emission factors during the motorway section were 70 – 90 mg/km for the Alpine routes and 50 mg/km for the RDE-routes.

Wang et al. (2018) reported higher emissions of CO and PN at higher altitude for a vehicle certified under China IV standard tested on-road at 30-2990 m.a.s.l. at 33-25°C. However, absolute CO and PN emissions for the vehicle were low. PN and CO emissions from diesel vehicles have been shown to be little affected by cold ambient temperatures [Suarez-Bertoa and Astorga, 2018].

Although PN emissions from the DV8 were higher during the cold and high altitude tests than during moderate conditions, they were relatively low (<6×10¹¹ #/km Euro 6 limit) during all the tests performed. PN emission factors ranged from 1×10¹¹ #/km during the RDE compliant routes (RDE-routes) to 2×10¹¹ #/km during Alpine-1.

Table 10. DV8’s emission factors of NOx (mg/km), PN (#/km), CO (mg/km) and CO₂ (g/km) during the RDE routes, the Alpine-1 route and the Alpine-2 route.

| DV RDE-routes | DV Alpine-1 | DV Alpine-2
| Comp. | Urb. | Rur. | MW | Comp. | Urb. | Rur. | MW | Comp. | Urb. | Rur. | MW.
NOx | 51 | 67 | 28 | 50 | 72 | 99 | 30 | 71 | 113 | 169 | 65 | 78
PN ×10¹¹ | 1.3 | 1.3 | 2 | 1.2 | 2.0 | 1.9 | 2.3 | 1.9 | 1.3 | 1.2 | 1.6 | 1.3
CO | 41 | 74 | 21 | 15 | 83 | 136 | 52 | 39 | 149 | 255 | 72 | 68
CO₂ | 134 | 136 | 115 | 145 | 134 | 129 | 117 | 157 | 143 | 138 | 124 | 168

Testing on higher positive road grade leads to faster heating of the DOC, and therefore higher efficiency of the catalyst to reduce CO emissions. In fact, CO emissions measured from the DV were relatively low during all the on-road tests. Emission factors during the urban section ranged from 74 mg/km (RDE-routes) to 255 mg/km (Alpine-2). The CO emissions measured for the DV8 during the Alpine tests were in line with those reported for Euro 6b vehicles tests at -7°C using the WLTP [Suarez-Bertoa and Astorga, 2018].

Average CO₂ emissions from the DV8 at cold temperatures and high altitude of the Alpine-1 route were comparable to the RDE-routes and 7% higher during Alpine-2 than during the RDE-routes.

2.2.2 Emissions from a Euro 6d-TEMP gasoline vehicle

NOx emissions from the GV9 were higher at colder temperatures. NOx emissions from the GV9 were surprisingly high during the Alpine tests, performed at temperatures that ranged from -8°C to -5°C, and during the test performed using the RDE compliant route, RDE-2. The emissions during the complete on-road tests were 113 – 178 mg/km. It should be noted that these are raw emissions and the correction factor (1.6) for extended conditions was not applied. Previous studies have shown that cold ambient temperatures lead to higher NOx emissions from gasoline vehicles as the light-off of the TWC takes longer at colder temperatures [Suarez-Bertoa and Astorga, 2018 and references therein]. Interestingly, urban emissions during Alpine-1, performed at -5°C, were low (44 mg/km), indicating that, for this vehicle, cold temperature or high altitude did not have a strong impact on the NOx emissions (Table 11).

NOx emissions during the urban section of Alpine-2 (170 mg/km), which starts with a steep slope, and during the motorway sections of Alpine-1 (367 mg/km) and Alpine-2 (290 mg/km), which faced certain length uphill (but also downhill), were ~8 times higher than during the urban section of RDE-routes (47 mg/km) and Alpine-1 (44 mg/km), which are relatively flat. This indicates that road grade may have a strong impact on the NOx emissions of this vehicle.

PN emissions for the GV9 were relatively high during most tests (7 – 8 ×10¹¹ #/km during the RDE-routes, Alpine-1) and very high during Alpine-2 (1.4×10¹² #/km). The urban section of the on-road routes presented the highest emission factors, ranging from 1.1×10¹² #/km during Alpine-1 to 2.3×10¹² #/km during Alpine-2. High PN emissions from PFI during cold temperature tests has been previously reported for laboratory studies [Suarez-Bertoa and Astorga, 2018; Zhu et al., 2017]. High PN emissions from PFI vehicles at cold temperature are linked to enrichment of the air-fuel mixture during cold-start engine operation, which compensates for the reduced fuel vaporization and elevated friction of engine components, leading to incomplete fuel combustion. PN emissions decrease as the engine gets warmer due to better combustion. However, PN emissions from the GV9 were high during the motorway section.

Table 11. GV9’s emission factors of NOx (mg/km), PN (#/km), CO (mg/km) and CO₂ (g/km) during the RDE routes, the Alpine-1 route and the Alpine-2 route.

| GV RDE-routes | GV Alpine-1 | GV Alpine-2
| Comp. | Urb. | Rur. | MW | Comp. | Urb. | Rur. | MW | Comp. | Urb. | Rur. | MW.
NOx | 113 | 47 | 42 | 88 | 176 | 44 | 138 | 367 | 178 | 170 | 91 | 290
PN ×10¹¹ | 8 | 13 | 4 | 4 | 6.6 | 11 | 3 | 4 | 14 | 23 | 6 | 9
CO | 125 | 215 | 45 | 127 | 135 | 261 | 40 | 57 | 155 | 265 | 64 | 73
CO₂ | 149 | 167 | 114 | 157 | 150 | 166 | 110 | 163 | 152 | 158 | 131 | 167

It is should be noticed that, at the time being, PN emissions from PFI vehicles are only regulated in China under China-6 regulation [China 6].

CO emissions from the GV9 were low during all the performed tests. CO emissions were comparable at the two studied temperatures and the other studied conditions. They ranged from 125 mg/km during the RDE-routes to 155 mg/km during Alpine-2. Although CO urban emission factors during the on-road test were two times higher than those obtained from the complete tests, they were relatively low (215 – 265 mg/km).

CO₂ emission factors during the cold and high altitude tests (Alpine-1 150 g/km and Alpine-2 152 g/km) were comparable to the tests performed in along the RDE compliant routes (149 g/km). In previous laboratory studies performed using the WLTP it was reported a ~16% increase on CO₂ emissions as the temperature decreased from 23°C to -7°C [Zhu et al., 2017; Suarez-Bertoa and Astorga, 2018].

2.2.3 Emissions from a Euro 6b gasoline plug-in hybrid vehicle

The ambient temperature together with the use of the PHEV’s heating system affected dramatically the use of the internal combustion engine (ICE) of the vehicle and consequently its emissions. During all the Alpine tests, where temperature was below -5°C, and when the heating system was activated, the ICE started as soon as the heating was enable, i.e., as soon as the test initiated (see Figure 7). The activation of the ICE was dependent of the ambient temperature. In fact, during RDE-routes the vehicle ran electric for ~1000s, even though the air-conditioning system was activated as soon as the car was ignited.

NOx emissions from the PHEV were very low (<9 mg/km) in most of the studied conditions (maximum NOx 33 mg/km during the Alpine-2). NOx emissions were comparable during the RDE compliant routes performed at 9°C (4 mg/km) and the Alpine-1 (performed at -5°C; 5 mg/km), which indicates that cold temperature and the maximum allowed altitude of RDE (1300m) did not appear to affect these emissions (Table 12). Similar as for the GV9, the highest NOx emissions were measured during the Alpine-2, which is the most demanding in terms of temperature, torque, and altitude. NOx emission factors during the urban section were also low (up to 32 mg/km).

While the Alpine-1 test yielded the highest CO emissions (1767 mg/km), the highest PN emissions were measured during the Alpine-2 test (1.0 ×10¹² #/km). However, the lowest CO emissions were measured during the Alpine-2 test (1010 mg/km) and the lowest PN emissions during the Alpine-1 test (3.5 ×10¹¹ #/km).

When the use of the heating system along the Alpine routes was taken into consideration, it was recorded that CO and PN emissions were approximatively three times higher when the heating system was disabled than when it was enabled (Table 13).

The highest CO emissions (3153 mg/km) were measured during Alpine-1 AUX-OFF, and the lowest during Alpine-2 AUX-ON (1010 mg/km). The highest PN emissions (3.2×10¹² #/km) were measured during Alpine-2 AUX-OFF, and the lowest during Alpine-1 AUX-ON (3.5×10¹¹ #/km).

Figure 7. CO₂ emission profile during the Alpine-1 tests performed with the PHEV at 12% battery state of charge (SOC) and with the air conditioning heating system enabled (AUX-ON) and disabled (AUX-OFF). CO₂ emissions are an indicator of the ICE operation.

Table 12. PHEV’s emission factors of NOx (mg/km), PN (#/km), CO (mg/km) and CO₂ (g/km) during the RDE routes, the Alpine-1 route and the Alpine-2 route.

| PHEV RDE-routes | PHEV Alpine-1 | PHEV Alpine-2
| Comp. | Urb. | Rur. | MW | Comp. | Urb. | Rur. | MW | Comp. | Urb. | Rur. | MW.
NOx | 4 | 1 | 2 | 2 | 5 | 7 | 1 | 4 | 33 | 32 | 35 | 33
PN ×10¹¹ | 9 | 9 | 3.3 | 4 | 3.5 | 4.9 | 3 | 2.1 | 10 | 14 | 10 | 3.9
CO | 1375 | 370 | 362 | 2477 | 1767 | 842 | 817 | 3710 | 1010 | 1090 | 630 | 1266
CO₂ | 152 | 82 | 159 | 220 | 140 | 89 | 143 | 203 | 174 | 183 | 146 | 188

The difference between AUX-OFF and AUX-ON on the CO and PN emissions was also observed during the laboratory tests using the WLTP at -7°C. As described in a previous study with other two PHEVs investigated in the laboratory at different conditions [Suarez-Bertoa et al., 2019], this difference may be linked to the way the engine and TWC are heated during the two different operations. When the heating system is enabled, the ICE initiate with the vehicle stopped and allows the engine and TWC to heat up on a more controlled manner during low load operations (similarly to a conventional vehicle). On the other hand, when the heating system is disabled the ICE kicks in at higher loads, while the vehicle is already running. The combination of the high load and cold engine/catalyst may result on incomplete combustion, i.e., high emissions of particles and CO, that a catalyst that has not reach light-off is not capable of reducing.

Table 13. PHEV’s emission factors of NOx (mg/km), CO (mg/km), PN (#/km), CO₂ (g/km), for the complete on-road tests, their sections (urban, rural and motorway (MW)) during the Alpine-1 and Alpine-2 tests performed with the PHEV at 12% battery SOC and with the air conditioning heating system enabled (AUX-ON) and disabled (AUX-OFF).

| PHEV Alpine-1 –AUX-ON | PHEV Alpine-1 – AUX-OFF
| Comp. | Urban | Rural | MW | Comp. | Urban | Rural | MW
NOx | 5 | 7 | 5 | 4 | 1 | 0 | 0 | 2
PN ×10¹¹ | 3.5 | 4.9 | 3.5 | 2.1 | 6.5 | 12 | 3.0 | 2.5
CO | 1767 | 842 | 1767 | 3710 | 3153 | 559 | 799 | 7935
CO₂ | 140 | 89 | 140 | 143 | 148 | 97 | 136 | 215

| PHEV Alpine-2 –AUX-ON | PHEV Alpine-2 – AUX-OFF
| Comp. | Urban | Rural | MW | Comp. | Urban | Rural | MW
NOx | 33 | 32 | 35 | 33 | 9 | 1 | 12 | 18
PN ×10¹¹ | 10 | 14 | 10 | 3.9 | 32 | 36 | 37 | 22
CO | 1010 | 1090 | 630 | 1266 | 2627 | 1916 | 1020 | 5082
CO₂ | 174 | 183 | 146 | 188 | 164 | 168 | 105 | 211

3   Conclusions

Our results indicate that, following the introduction of the RDE procedure in EU, more efficient and complex emission control are being used to reduce the emissions of the pollutants, particularly NOx, from diesel vehicles. Consequently, the selected diesel vehicles exhibit markedly lower NOx emissions than earlier Euro 6 diesel vehicles for the RDE-compliant tests and for some of the most demanding tests outside RDE boundary conditions. This is a promising indication of the capability of RDE-compliant vehicles (Euro 6d-TEMP and later) to deliver consistently low-NOx emission performance. Nonetheless, during the Dynamic tests the NOx emission factors were higher than Euro 6 limits even for some Euro 6d-TEMP diesel vehicles and gasoline vehicles studied.

CO emissions from gasoline vehicles during dynamic tests were more than five times higher than those obtained during the RDE compliant tests. This indicates some of the limitations of the current procedure, which does not include measuring CO.

PN emissions from gasoline vehicles (including PFIs) were up to three orders of magnitude higher than those obtained from diesel vehicles. PN median emissions were two times higher during the dynamic routes (2×10¹² #/km) than during the RDE routes (1×10¹² #/km).

Tests performed at cold ambient temperature and high altitude, outside the RDE boundary conditions, resulted in higher emission of NOx and CO than those obtained when vehicles were tested on RDE compliant routes and moderate conditions of temperature and altitude. Nonetheless, the two Euro 6d-TEMP vehicles tested in those extreme conditions yielded NOx emissions factors that fulfilled the Euro 6d-TEMP emission requirements.

Raw emissions of criteria pollutants from the Euro 6d-TEMP vehicles were below Euro 6d-TEMP on-road emission requirements even when considering the fact that the correction for RDE extended conditions (1.6 factor) was not applied. Our Alpine tests were performed entirely at RDE extended conditions (or beyond) for both altitude and temperature.

The ambient temperature together with the use of the PHEV’s heating system affected how the ICE is used and the emissions. Although NOx emissions (4 – 33 mg/km) from the PHEV, a PFI vehicle Euro 6b compliant, were low at all the studied conditions, CO (1010 – 1767 mg/km) and PN (3.5 ×10¹¹ – 1.0 ×10¹² #/km) emissions were high in some cases.

Emission factors obtained in this study will allow updating current vehicle emissions inventories providing real world emissions of pollutants, that in some cases (CO and PN from PFI) is rather limited in the literature. Moreover, the study presents the first results of vehicles type-approved under the most stringent emission standards at the moment (Euro 6d-TEMP) investigated under different real-world driving situations.

3.1 Recommendations

• Our work underlines the urgent necessity of a technology- and fuel-neutral approach to vehicle emission standards, whereby all vehicles must comply with the same emission limits for all pollutants.

• CO and PN emissions from PFI gasoline vehicles are not regulated currently by RDE. However, it has been shown that their emissions can be high. Therefore, it is advisable to include them along with NOx in the RDE procedure.

• Correction factor for RDE extended conditions (1.6 dividing factor) is not shown to be necessary.

Summary of the outcomes

Box 3. Summary of the outcomes.

1. On road emissions of NOx, PN, NO₂, CO and CO₂ from nineteen Euro 6b+ vehicles, including diesel (3 of which Euro 6d-temp) gasoline (GDI and PFI) and CNG vehicles, were investigated following RDE standard procedure and other real world operations not covered by the RDE (dynamic driving style, different shares of operation) using 4 different routes.

Euro 6d-TEMP diesel vehicles exhibit markedly lower NOx emissions than earlier Euro 6 diesel vehicles for the RDE-compliant tests and for some of the more demanding tests outside RDE boundary conditions.

When equipped with a GPF, GDI cars can meet RDE requirements for PN on-road emissions.

Gasoline PFI vehicles can present high PN emissions during RDE tests.

When driven outside the RDE dynamicity boundaries:

Gasoline cars often presented high CO emissions during dynamic RDE tests;

NOx emissions increased for diesel cars, including Euro 6d-TEMP;

NOx emissions from some gasoline cars were higher than the Euro 6 limit (60mg/km x CF 2.1);

PN emissions from gasoline cars were higher than 6×10¹¹ #/km (except for the GPF-equipped car).

2. On-road emissions of NOx, CO, PN and CO₂ from two Euro 6d-TEMP certified vehicles, one diesel (DV8) one gasoline (GV9), and one Euro 6b plug-in hybrid vehicle (PHEV) were investigated at sub-zero ambient temperatures and high altitudes.

Emissions were higher at cold temperature and high altitude (>1300m) than at RDE moderate temperature and altitude conditions.

Ambient temperature together with the use of the heating system of the PHEV’s strongly and negatively impacted the emissions of CO and PN.

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List of abbreviations

AES | Auxiliary Emissions Strategy
CI | Compressed Ignition
CNG | Compressed natural gas
CNG-LCV | Compressed natural gas-Light commercial vehicle
CVS | Constant Volume Sampler
CVS 75 | Constant Volume Sampling 75
DOC | Diesel Oxidation Catalyst
DPF | Diesel Particle Filter
EGR | Exhaust Gas Recirculation
ERMES | European Research for Mobile Emission Sources
FTP | Federal Test Procedure
GDI | Gasoline Direct Injection
GPF | Gasoline Particle Filter
HC | Hydrocarbons
LNT | Lean NOx Catalyst
NMHC | Non-Methane Hydrocarbons
NTE | Not-To-Exceed Limit
PFI | Port Fuel Injection
PHEV | plug-in hybrid vehicle
PI | Positive Ignition
PN | Particle Number
pSCR | Passive Selective Catalyst Reaction
RDE | Real Driving Emission
SCR | Selective Catalyst Reaction
SOC | State Of Charge
THC | Total Hydrocarbons
TWC | Three Way Catalyst
UDC | Urban Driving Cycle
WHO | World Health Organization

List of boxes

Box 1. Objectives of the experimental program.

Box 2. Supporting material and information.

Box 3. Summary of the outcomes.

List of figures

Figure 1. Cold ambient laboratory test for light-duty vehicles. Global state of play.

Figure 2. NOx median emissions factors from diesel (left plot) and gasoline (right plot) vehicles

Figure 3. NO₂ median emissions factors from diesel (left plot) and gasoline (right plot) vehicles

Figure 4. PN median emissions factors from diesel (left plot) and gasoline (right plot) vehicles

Figure 5. CO median emissions factors from diesel (left plot) and gasoline (right plot) vehicles

Figure 6. CO₂ median emissions factors from diesel (left plot) and gasoline (right plot) vehicles

Figure 7. CO₂ emission profile during the Alpine-1 tests performed with the PHEV at 12% battery state of charge (SOC) and with the air conditioning heating system enabled (AUX-ON) and disabled (AUX-OFF). CO₂ emissions are an indicator of the ICE operation.

List of tables

Table 1. Some of the requirements and boundary conditions for a test to be RDE compliant.

Table 2. Trips characteristics. Bold indicates that the value is outside RDE boundary conditions.

Table 3. Vehicle specifications. Gasoline vehicles (GV), plug-in hybrid vehicle (PHEV) and compressed natural gas light commercial vehicle (CNG-LCV).

Table 4. Diesel vehicle (DV) specifications.

Table 5. Emission factors of NOx (mg/km) during the RDE, Dynamic (Dyn.), City-Motorway (City-MW) and Hill tests. The emissions factors presented in the columns RDE and Dyn. are the average of the emissions obtained along the two different routes (RDE-1 and RDE-2) tested using these two different driving dynamics (RDE and Dynamic)

Table 6. Emission factors of NO₂ (mg/km) during the RDE, Dynamic (Dyn.), City-Motorway (City-MW) and Hill tests. The emissions factors presented in the columns RDE and Dyn. are the average of the emissions obtained along the two different routes (RDE-1 and RDE-2) tested using these two different driving dynamics (RDE and Dynamic).

Table 7. Emission factors of PN (×10¹¹ #/km) during the RDE, Dynamic (Dyn.), City-Motorway (City-MW) and Hill tests. The emissions factors presented in the columns RDE and Dyn. are the average of the emissions obtained along the two different routes (RDE-1 and RDE-2) tested using these two different driving dynamics (RDE and Dynamic).

Table 8. Emission factors of CO (mg/km) during the RDE, Dynamic (Dyn.), City-Motorway (City-MW) and Hill tests. The emissions factors presented in the columns RDE and Dyn. are the average of the emissions obtained along the two different routes (RDE-1 and RDE-2) tested using these two different driving dynamics (RDE and Dynamic)

Table 9. Emission factors of CO₂ (g/km) during the RDE, Dynamic (Dyn.), City-Motorway (City-MW) and Hill tests. The emissions factors presented in the columns RDE and Dyn. are the average of the emissions obtained along the two different routes (RDE-1 and RDE-2) tested using these two different driving dynamics (RDE and Dynamic).

Table 10. DV8’s emission factors of NOx (mg/km), PN (#/km), CO (mg/km) and CO₂ (g/km) during the RDE, Dynamic (Dyn.), City-Motorway (City-MW) and Hill

Table 11. GV9’s emission factors of NOx (mg/km), PN (#/km), CO (mg/km) and CO₂ (g/km) during the RDE, Dynamic (Dyn.), City-Motorway (City-MW) and Hill

Table 12. PHEV’s emission factors of NOx (mg/km), PN (#/km), CO (mg/km) and CO₂ (g/km) during the RDE, Dynamic (Dyn.), City-Motorway (City-MW) and Hill

Table 13. PHEV’s emission factors of NOx (mg/km), CO (mg/km), PN (#/km), CO₂ (g/km), for the complete on-road tests, their sections (urban, rural and motorway (MW)) during the Alpine-1 and Alpine-2 tests performed with the PHEV at 12% battery SOC and with the air conditioning heating system enabled (AUX-ON) and disabled (AUX-OFF).

Annexes

Annex 1. Measurements

The vehicles used in this study were selected to be a representative sample of the European market for new vehicles. The tested fleet included some of the best-selling models from different manufacturers across vehicle segments and engine sizes. The vehicles were equipped with the usual exhaust after-treatment technologies in the EU for new cars sold between 2016 and 2018. Gasoline vehicles used either port fuel injection (PFI) or direct injection (GDI) technology. One gasoline vehicle (GV8) was equipped with a gasoline particulate filter (GPF). All diesel vehicles were equipped with an exhaust gas recirculation (EGR) system and either a lean NOx trap (LNT), selective catalytic reduction (SCR) or both (DV9) to control NOx emissions. One diesel vehicle (DV10, type-approved to Euro 6d-TEMP) was equipped with a dual LNT and a passive SCR (not requiring urea solution refills).

All vehicles were tested using the applicable laboratory procedures for exhaust emissions, i.e., WLTP [EU 2017/1151] for vehicles DV8, DV9 and DV10, and Type 1 test according to UNECE Regulation 83 for all others (see [Clairotte et al, 2018; Suarez-Bertoa and Astorga 2018] for a complete description of the tests). The corresponding Euro 6 limits were met in all cases. Compliance with the emission limits over the laboratory test was taken as indication that the vehicles were free of malfunctions that could result in abnormally high emissions.

The measurement of the instantaneous, on-road emissions of NOx, NO₂, CO, PN and/or CO₂ were performed using PEMS. Vehicles DV1 and PHEV were tested using a Semtech Ecostar system (Sensors, Saline, Michigan, USA – model 2013), and all other vehicles were tested using an AVL MOVE system (AVL, Graz, Austria – model 2016). Both PEMS systems consist of a tailpipe attachment, heated exhaust lines, an exhaust flow meter (EFM), exhaust gas analyzers, a solid particle counter, data logger connected to vehicle network, a GPS and a weather station for ambient temperature and humidity measurements. Both systems measure exhaust gas concentrations of CO and CO₂ by a non-dispersive infrared sensor, and NO and NO₂ by a non-dispersive ultra-violet sensor. NOx is calculated by the sum of the concentrations of NO and NO₂. PN was measured by means of diffusion charge methodology using the MOVE (GV5-GV9, DV3, DV7-DV10) or by condensation particle counter (CPC) using a TSI NPET 3795, modified by HORIBA to reach higher concentrations (GV1-GV4, DV1, DV2, DV4 – DV6, CNG-LCV and PHEV). A stand-alone Testo3 analyser (NanoMet3), which also measures PN means of diffusion charge methodology, was used for the PHEV during Alpine-1 and Alpine-2 tests. EFM uses a Pitot tube to calculate flow rate. All relevant emissions data were recorded at a frequency of 1 Hz. The PEMS used in the described experimental campaign are routinely validated on the chassis dynamometer as recommended by RDE regulation.

The emission factors reported here were calculated by integrating the total mass emissions measured during the test and dividing the obtained value by the driven distance, as estimated from the GPS velocity signal. These are the so-called ‘raw’ emissions (without using the weighting function based on CO₂ emissions as introduced in the fourth package of the RDE regulation) [EU 2018/1832].

The PHEV was tested along Alpine-1 and Alpine-2 activating and deactivating the air heating system (set in automatic mode at 21°C when activated; hereinafter, A/C-ON and A/C-OFF, respectively). For PHEV, RDE-routes was only performed using the air heating system.

Annex 2. Routes

Table 2 summarizes the main characteristics of the routes used. Route RDE-1 and Route RDE-2 were designed to fulfil all the requirements of the RDE procedure. Route City-Motorway presents a different sequence of vehicle operation (City-Motorway-City-Motorway-City instead of the usual urban-rural-motorway), and urban and motorway shares are longer than allowed by RDE. Route Hill has a positive altitude gain outside RDE boundaries (~1800m), and it comprises only urban operation.
Vehicles were tested fulfilling RDE requirements along route RDE-1 and route RDE-2. Then, they were tested through the two same routes using a more dynamic driving style (i.e., seeking an increase in the 95th percentile of v*a). Even if dynamic tests presented higher v*a, some of these tests fulfilled the Max. 95th percentile of v*a RDE boundary. The higher dynamicity was achieved for example by faster starts after fully stopping the vehicle at traffic lights or engaging lower gears when using manual transmission. All the dynamic tests were performed respecting the traffic code.

For the tests performed in the Alpine area, Alpine-1 fulfils all the requirements of the RDE procedure with the exception on the maximum altitude, which is slightly above (aprox. 1380m) the maximum allowed for an RDE test, 1300m. Alpine-2 fulfils some of the requirements of the RDE procedure such as: section sequence (urban, rural and motorway), share of operation, driving dynamics, among others, but explores altitudes (Max. 2000 m) and positive altitude gain (>1200m/100km) outside RDE boundaries.

Route# 1 – RDE-1

Total Distance [km] | Ca. 79
Urban Rural Motorway Distance Shares [%] | 38.5 – 27.5 – 34.0
Average speed [km/h] | 48.8
Average urban speed [km/h] | 27.5
Cumulative altitude gain [m/100km] | 631

Route# 2 – RDE-2

Total Distance [km] | Ca. 94
Urban Rural Motorway Distance Shares [%] | 36.7 – 25.7 – 37.6
Average speed [km/h] | 51.0
Average urban speed [km/h] | 27.5
Cumulative altitude gain [m/100km] | 739

Route# 3 - Hill

Total Distance | Ca. 62
Urban Rural Motorway Distance Shares [%] | 95.5 – 4.5 – 0%
Average speed [km/h] | 34.5
Average urban speed [km/h] | 33.8
Cumulative altitude gain [m/100km] | 1800

Route# 4 – City-Motorway

Total Distance | Ca. 141
Urban Rural Motorway Distance Shares [%] | 30.1 – 13.7 – 56.2
Average speed [km/h] | 60.3
Average urban speed [km/h] | 30.9
Cumulative altitude gain [m/100km] | 374

Annex 3. Emission Factors

Emission factors of NOx (mg/km), NO₂ (mg/km), CO (mg/km), CO₂ (g/km) and PN (#/km) for the tested vehicles D1-D10, GV1-GV8 and CNG during the complete on-road tests (C.) and the sub-sections: urban (U.), rural (R.) and motorway (MW).

DV1

| RDE-1 |  | RDE-2 |  | RDE-1-Dyn |  | RDE-2-Dyn |  | City-MW |  | Hill
| C. | U. | R. | MW |  | C. | U. | R. | MW |  | C. | U. | R. | MW. |  | C. | U. | R. | MW. |  | C. | U. | R. | MW. |  | C./Urb
NOx | 474 | 279 | 385 | 869 |  | 477 | 296 | 336 | 872 |  | 646 | 525 | 494 | 973 |  | 759 | 523 | 433 | 1326 |  |  |  |  |  |  | 639
NO₂ | 120 | 90 | 127 | 157 |  | 141 | 113 | 140 | 178 |  | 187 | 149 | 157 | 269 |  | 165 | 156 | 130 | 207 |  |  |  |  |  |  | 236
CO | 262 | 258 | 151 | 409 |  | 405 | 349 | 235 | 666 |  | 298 | 378 | 266 | 228 |  | 188 | 197 | 104 | 256 |  |  |  |  |  |  | 205
CO₂ | 187 | 220 | 143 | 196 |  | 189 | 218 | 135 | 210 |  | 204 | 257 | 150 | 197 |  | 202 | 229 | 145 | 223 |  |  |  |  |  |  | 381
PN ×10¹¹ |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |

DV2

| RDE-1 |  | RDE-2 |  | RDE-1-Dyn |  | RDE-2-Dyn |  | City-MW |  | Hill
| C. | U. | R. | MW |  | C. | U. | R. | MW |  | C. | U. | R. | MW. |  | C. | U. | R. | MW. |  | C. | U. | R. | MW. |  | C./Urb
NOx | 483 | 260 | 525 | 775 |  | 620 | 472 | 515 | 884 |  | 628 | 392 | 679 | 886 |  | 939 | 682 | 872 | 1252 |  | 799 | 810 | 615 | 837 |  | 405
NO₂ | 108 | 97 | 151 | 74 |  | 139 | 186 | 190 | 42 |  | 94 | 125 | 101 | 46 |  | 155 | 213 | 190 | 71 |  | 207 | 466 | 191 | 58 |  | 97
CO | 30 | 63 | 10 | 2 |  | 20 | 40 | 4 | 7 |  | 38 | 48 | 37 | 28 |  | 12 | 22 | 2 | 10 |  | 32 | 81 | 19 | 5 |  | 129
CO₂ | 134 | 151 | 106 | 141 |  | 144 | 152 | 108 | 163 |  | 153 | 169 | 136 | 153 |  | 155 | 167 | 131 | 160 |  | 145 | 157 | 118 | 145 |  | 155
PN ×10¹¹ |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |

DV3

| RDE-1 |  | RDE-2 |  | RDE-1-Dyn |  | RDE-2-Dyn |  | City-MW |  | Hill
| C. | U. | R. | MW |  | C. | U. | R. | MW |  | C. | U. | R. | MW. |  | C. | U. | R. | MW. |  | C. | U. | R. | MW. |  | C./Urb
NOx | 551 | 412 | 433 | 882 |  | 586 | 445 | 414 | 893 |  | 998 | 907 | 770 | 1378 |  | 1011 | 762 | 904 | 1376 |  | 673 | 496 | 659 | 762 |  | 641
NO₂ | 117 | 81 | 97 | 191 |  | 136 | 103 | 105 | 199 |  | 191 | 156 | 153 | 281 |  | 188 | 131 | 165 | 271 |  | 139 | 88 | 164 | 161 |  | 113
CO | 28 | 39 | 23 | 20 |  | 21 | 33 | 8 | 17 |  | 106 | 155 | 48 | 106 |  | 44 | 83 | 46 | 1 |  | 34 | 78 | 8 | 17 |  | 103
CO₂ | 154 | 156 | 135 | 173 |  | 156 | 153 | 128 | 181 |  | 164 | 173 | 145 | 174 |  | 165 | 156 | 151 | 186 |  | 158 | 147 | 120 | 169 |  | 148
PN ×10¹ | 0.03 | 0.06 | <0.01 | <0.01 |  | <0.01 | <0.01 | <0.01 | <0.01 |  | 0.01 | <0.01 | <0.01 | <0.01 |  | <0.01 | <0.01 | <0.01 | <0.01 |  | <0.01 | <0.01 | <0.01 | <0.01 |  | 0.04

DV4

| RDE-1 |  | RDE-2 |  | RDE-1-Dyn |  | RDE-2-Dyn |  | City-MW |  | Hill
| C. | U. | R. | MW |  | C. | U. | R. | MW |  | C. | U. | R. | MW. |  | C. | U. | R. | MW. |  | C. | U. | R. | MW. |  | C./U.
NOx | 146 | 122 | 143 | 182 |  | 147 | 124 | 168 | 156 |  | 684 | 673 | 749 | 643 |  | 605 | 661 | 748 | 448 |  | 179 | 100 | 156 | 230 |  | 203
NO₂ | 42 | 32 | 40 | 56 |  | 41 | 32 | 47 | 46 |  | 162 | 146 | 186 | 159 |  | 152 | 160 | 189 | 117 |  | 38 | 26 | 37 | 46 |  | 53
CO | 5 | 4 | 8 | 4 |  | 5 | 5 | 6 | 3 |  | 9 | 11 | 7 | 10 |  | 3 | 0 | 0 | 9 |  | 9 | 5 | 1 | 13 |  | 4
CO₂ | 160 | 193 | 132 | 146 |  | 155 | 179 | 131 | 147 |  | 174 | 212 | 147 | 155 |  | 172 | 209 | 139 | 161 |  | 152 | 170 | 111 | 152 |  | 173
PN ×10¹¹ |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |

DV5

| RDE-1 |  | RDE-2 |  | RDE-1-Dyn |  | RDE-2-Dyn |  | City-MW |  | Hill
| C. | U. | R. | MW |  | C. | U. | R. | MW |  | C. | U. | R. | MW. |  | C. | U. | R. | MW. |  | C. | U. | R. | MW. |  | C./U.
NOx | 21 | 22 | 17 | 25 |  | 44 | 39 | 9 | 79 |  | 28 | 30 | 22 | 31 |  | 141 | 130 | 86 | 203 |  |  |  |  |  |  | 59
NO₂ | 5 | 5 | 3 | 5 |  | 8 | 6 | 2 | 15 |  | 4 | 5 | 3 | 4 |  | 15 | 14 | 7 | 23 |  |  |  |  |  |  | 16
CO | 45 | 26 | 93 | 22 |  | 25 | 29 | 35 | 12 |  | 20 | 33 | 4 | 21 |  | 51 | 45 | 115 | 0 |  |  |  |  |  |  | 57
CO₂ | 157 | 188 | 131 | 140 |  | 155 | 189 | 128 | 140 |  | 170 | 235 | 122 | 139 |  | 183 | 247 | 145 | 154 |  |  |  |  |  |  | 194
PN ×10¹¹ | 0.03 | 0.03 | 0.03 | 0.02 |  | 0.3 | 0.6 | 0.08 | 0.07 |  | 1.5 | 3.8 | 0.3 | 0.2 |  | - | - | - | - |  |  |  |  |  |  | -

DV6

| RDE-1 |  | RDE-2 |  | RDE-1-Dyn |  | RDE-2-Dyn |  | City-MW |  | Hill
| C. | U. | R. | MW |  | C. | U. | R. | MW |  | C. | U. | R. | MW. |  | C. | U. | R. | MW. |  | C. | U. | R. | MW. |  | C./Urb
NOx | 75 | 89 | 45 | 88 |  | 81 | 84 | 81 | 77 |  | 376 | 325 | 367 | 449 |  | 224 | 256 | 162 | 248 |  | 141 | 131 | 88 | 173 |  | 93
NO₂ | 21 | 23 | 18 | 22 |  | 23 | 28 | 22 | 19 |  | 126 | 107 | 109 | 168 |  | 82 | 78 | 56 | 111 |  | 67 | 47 | 40 | 92 |  | 38
CO | 26 | 57 | 5 | 6 |  | 0 | 0 | 0 | 0 |  | 0 | 0 | 0 | 0 |  | 60 | 199 | 0 | 0 |  | 21 | 43 | 11 | 12 |  | 4
CO₂ | 150 | 178 | 127 | 134 |  | 149 | 175 | 133 | 133 |  | 156 | 186 | 138 | 139 |  | 168 | 228 | 120 | 146 |  | 137 | 163 | 110 | 134 |  | 197
PN ×10¹¹ | 5.4 | 8.5 | 4.4 | 1.9 |  | 4.6 | 7.6 | 4.0 | 1.9 |  | 6.1 | 8.4 | 5.4 | 4.0 |  | 6.0 | 13 | 2.5 | 1.6 |  | 3.4 | 6.2 | 3.13 | 1.8 |  | -

DV7

| RDE-1 |  | RDE-2 |  | RDE-1-Dyn |  | RDE-2-Dyn |  | City-MW |  | Hill
| C. | U. | R. | MW |  | C. | U. | R. | MW |  | C. | U. | R. | MW. |  | C. | U. | R. | MW. |  | C. | U. | R. | MW. |  | C./Urb
NOx | 17 | 30 | 9 | 7 |  | 9 | 13 | 4 | 9 |  | 40 | 67 | 23 | 23 |  | 38 | 75 | 24 | 12 |  | 13 | 25 | 23 | 6 |  | 31
NO₂ | 0 | 1 | 0 | 0 |  | 1 | 1 | 1 | 1 |  | 2 | 5 | 0 | 0 |  | 2 | 2 | 1 | 1 |  | 2 | 3 | 3 | 2 |  | 1
CO | 40 | 52 | 29 | 36 |  | 0 | 0 | 0 | 0 |  | 49 | 65 | 36 | 41 |  | 4 | 10 | 0 | 0 |  | 30 | 45 | 27 | 23 |  | 65
CO₂ | 151 | 182 | 120 | 142 |  | 153 | 178 | 121 | 151 |  | 152 | 182 | 122 | 145 |  | 153 | 185 | 122 | 148 |  | 135 | 147 | 116 | 133 |  | 162
PN ×10¹¹ | 0.05 | 0.09 | 0.03 | 0.02 |  | 0.06 | 0.07 | 0.03 | 0.07 |  | 0.3 | 0.3 | 0.3 | 0.1 |  | 0.1 | 0.2 | 0.2 | 0.1 |  | 0.3 | 0.7 | 1 | 0.6 |  | 0.03

DV8

| RDE-1 |  | RDE-2 |  | RDE-1-Dyn |  | RDE-2-Dyn |  | City-MW |  | Hill
| C. | U. | R. | MW |  | C. | U. | R. | MW |  | C. | U. | R. | MW. |  | C. | U. | R. | MW. |  | C. | U. | R. | MW. |  | C./Urb
NOx | 31 | 35 | 26 | 29 |  | 89 | 61 | 71 | 138 |  | 318 | 252 | 267 | 464 |  | 57 | 101 | 29 | 31 |  | 19 | 29 | 13 | 15 |  | 72
NO₂ | 4 | 4 | 2 | 6 |  | 8 | 3 | 7 | 15 |  | 23 | 15 | 17 | 40 |  | 4 | 3 | 4 | 4 |  | 0 | 0 | 0 | 0 |  | 0
CO | 0 | 12 | 0 | 0 |  | 40 | 57 | 22 | 33 |  | 6 | 6 | 3 | 10 |  | 55 | 73 | 40 | 47 |  | 0 | 0 | 0 | 0 |  | 25
CO₂ | 134 | 144 | 113 | 138 |  | 143 | 155 | 117 | 151 |  | 159 | 184 | 127 | 162 |  | 141 | 155 | 112 | 150 |  | 131 | 126 | 103 | 138 |  | 140
PN ×10¹¹ | 0.7 | 0.7 | 0.7 | 0.5 |  | 0.6 | 0.6 | 0.5 | 0.5 |  | 0.7 | 1 | 0.6 | 0.5 |  | 0.7 | 0.8 | 0.6 | 0.5 |  | 0.6 | 0.7 | 0.6 | 0.6 |  | 0.5

DV9

| RDE-1 |  | RDE-2 |  | RDE-1-Dyn |  | RDE-2-Dyn |  | City-MW |  | Hill
| C. | U. | R. | MW |  | C. | U. | R. | MW |  | C. | U. | R. | MW. |  | C. | U. | R. | MW. |  | C. | U. | R. | MW. |  | C./Urb
NOx | 59 | 70 | 43 | 58 |  | 54 | 63 | 41 | 57 |  | 321 | 327 | 318 | 316 |  | 317 | 382 | 225 | 326 |  | 34 | 46 | 40 | 26 |  | 51
NO₂ | 17 | 22 | 12 | 15 |  | 8 | 10 | 6 | 8 |  | 40 | 39 | 37 | 44 |  | 39 | 43 | 26 | 45 |  | 0 | 0 | 0 | 0 |  | 1
CO | 8 | 8 | 1 | 15 |  | 0 | 0 | 0 | 0 |  | 0 | 0 | 0 | 0 |  | 0 | 0 | 0 | 0 |  | 0 | 0 | 0 | 0 |  | 0
CO₂ | 188 | 221 | 156 | 178 |  | 188 | 215 | 155 | 187 |  | 210 | 247 | 171 | 203 |  | 208 | 259 | 160 | 193 |  | 171 | 196 | 150 | 160 |  | 202
PN ×10¹¹ | 0.02 | 0.03 | 0.02 | 0.02 |  | 0.02 | 0.03 | 0.02 | 0.02 |  | 0.06 | 0.08 | 0.05 | 0.05 |  | 0.06 | 0.1 | 0.04 | 0.03 |  | <0.01 | <0.01 | <0.01 | <0.01 |  | 0.02

DV10

| RDE-1 |  | RDE-2 |  | RDE-1-Dyn |  | RDE-2-Dyn |  | City-MW |  | Hill
| C. | U. | R. | MW |  | C. | U. | R. | MW |  | C. | U. | R. | MW. |  | C. | U. | R. | MW. |  | C. | U. | R. | MW. |  | C./Urb
NOx | 92 | 32 | 39 | 242 |  | 145 | 47 | 47 | 337 |  | 385 | 316 | 236 | 627 |  | 290 | 273 | 219 | 376 |  | 89 | 26 | 67 | 136 |  |
NO₂ | 22 | 7 | 11 | 55 |  | 31 | 8 | 12 | 71 |  | 125 | 94 | 88 | 202 |  | 94 | 74 | 93 | 119 |  | 16 | 0 | 15 | 30 |  |
CO | 47 | 45 | 36 | 64 |  | 23 | 5 | 11 | 51 |  | 40 | 42 | 39 | 40 |  | 8 | 0 | 1 | 35 |  | 56 | 41 | 20 | 74 |  |
CO₂ | 169 | 199 | 137 | 162 |  | 169 | 197 | 138 | 162 |  | 165 | 196 | 134 | 157 |  | 159 | 186 | 126 | 157 |  | 151 | 175 | 123 | 142 |  |
PN ×10¹¹ | 0.03 | 0.03 | 0.02 | 0.02 |  | 0.02 | 0.02 | 0.01 | 0.02 |  | 0.1 | 0.2 | 0.06 | 0.04 |  | 0.04 | 0.06 | 0.04 | 0.03 |  | 0.01 | 0.02 | 0.01 | 0.01 |  |

GV1

| RDE-1 |  | RDE-2 |  | RDE-1-Dyn |  | RDE-2-Dyn |  | City-MW |  | Hill
| C. | U. | R. | MW |  | C. | U. | R. | MW |  | C. | U. | R. | MW. |  | C. | U. | R. | MW. |  | C. | U. | R. | MW. |  | C./Urb
NOx | 6 | 8 | 7 | 3 |  | 6 | 9 | 5 | 2 |  | 14 | 25 | 10 | 2 |  | 11 | 18 | 10 | 5 |  | 9 | 11 | 13 | 5 |  | 8
NO₂ | 0 | 0 | 0 | 0 |  | 0 | 0 | 0 | 0 |  | 0 | 0 | 0 | 0 |  | 0 | 0 | 0 | 0 |  | 0 | 0 | 0 | 0 |  | 0
CO | 699 | 352 | 766 | 1127 |  | 662 | 447 | 172 | 1360 |  | 1494 | 645 | 1927 | 2249 |  | 4163 | 2484 | 4581 | 5709 |  | 370 | 315 | 264 | 439 |  | 1046
CO₂ | 158 | 151 | 149 | 179 |  | 152 | 152 | 127 | 174 |  | 171 | 179 | 155 | 177 |  | 162 | 151 | 153 | 183 |  | 163 | 165 | 120 | 175 |  | 140
PN ×10¹¹ | 3.9 | 3.1 | 4.2 | 4.8 |  | 7.4 | 6.5 | 6.1 | 9.5 |  | 11 | 10 | 11 | 12 |  | 11 | 12 | 10 | 10 |  | 2.6 | 1.8 | 2.6 | 3.0 |  | 10

GV2

| RDE-1 |  | RDE-2 |  | RDE-1-Dyn |  | RDE-2-Dyn |  | City-MW |  | Hill
| C. | U. | R. | MW |  | C. | U. | R. | MW |  | C. | U. | R. | MW. |  | C. | U. | R. | MW. |  | C. | U. | R. | MW. |  | C./Urb
NOx | 13 | 20 | 6 | 10 |  | 16 | 19 | 8 | 20 |  | 13 | 19 | 10 | 6 |  | 11 | 16 | 7 | 9 |  | 11 | 15 | 9 | 9 |  | 19
NO₂ | 2 | 2 | 1 | 2 |  | 4 | 4 | 3 | 4 |  | 3 | 3 | 3 | 4 |  | 3 | 2 | 2 | 3 |  | 3 | 3 | 3 | 3 |  | 3
CO | 3344 | 149 | 1011 | 10910 |  | 1039 | 242 | 343 | 2666 |  | 6727 | 3078 | 4598 | 14101 |  | 5741 | 1979 | 3930 | 11443 |  | 2234 | 145 | 773 | 4121 |  | 450
CO₂ | 154 | 188 | 119 | 146 |  | 157 | 186 | 122 | 150 |  | 155 | 196 | 122 | 135 |  | 149 | 169 | 123 | 148 |  | 135 | 156 | 108 | 129 |  | 166
PN ×10¹¹ | 2.0 | 3.9 | 0.6 | 0.8 |  |  |  |  |  |  | 5.4 | 10 | 2.6 | 1.8 |  | 3.5 | 6.7 | 1. | 1.1 |  | 1.7 | 3.9 | 0.7 | 0.5 |  | 5.1

GV3

| RDE-1 |  | RDE-2 |  | RDE-1-Dyn |  | RDE-2-Dyn |  | City-MW |  | Hill
| C. | U. | R. | MW |  | C. | U. | R. | MW |  | C. | U. | R. | MW. |  | C. | U. | R. | MW. |  | C. | U. | R. | MW. |  | C./Urb
NOx | 38 | 73 | 19 | 7 |  | 39 | 58 | 50 | 7 |  | 25 | 41 | 23 | 6 |  | 41 | 91 | 20 | 6 |  | 21 | 53 | 7 | 5 |  | 56
NO₂ | 0 | 1 | 0 | 0 |  | 1 | 1 | 1 | 1 |  | 0 | 0 | 0 | 0 |  | 0 | 1 | 0 | 0 |  | 0 | 0 | 0 | 0 |  | 3
CO | 170 | 149 | 202 | 162 |  | 245 | 223 | 156 | 350 |  | 1398 | 382 | 1831 | 2255 |  | 1057 | 368 | 1782 | 1146 |  | 455 | 185 | 724 | 561 |  | 167
CO₂ | 135 | 166 | 105 | 126 |  | 123 | 111 | 120 | 139 |  | 152 | 183 | 127 | 135 |  | 145 | 156 | 131 | 145 |  | 137 | 153 | 99 | 134 |  | 156
PN ×10¹¹ | 11 | 20 | 51 | 7.2 |  | 12 | 12 | 9.4 | 15 |  | 25 | 46 | 9.9 | 14 |  | 31 | 65 | 11 | 13 |  | 8.9 | 11 | 5.0 | 8.7 |  | 19

GV4

| RDE-1 |  | RDE-2 |  | RDE-1-Dyn |  | RDE-2-Dyn |  | City-MW |  | Hill
| C. | U. | R. | MW |  | C. | U. | R. | MW |  | C. | U. | R. | MW. |  | C. | U. | R. | MW. |  | C. | U. | R. | MW. |  | C./Urb
NOx | 98 | 119 | 152 | 11 |  | 84 | 142 | 91 | 11 |  | 91 | 189 | 36 | 18 |  | 95 | 223 | 31 | 11 |  | 62 | 124 | 112 | 8 |  | 288
NO₂ | 2 | 2 | 2 | 2 |  | 2 | 2 | 1 | 2 |  | 3 | 4 | 2 | 3 |  | 2 | 3 | 2 | 3 |  | 2 | 3 | 2 | 2 |  | 2
CO | 1022 | 364 | 667 | 2323 |  | 958 | 405 | 354 | 2115 |  | 1838 | 1613 | 1446 | 2594 |  | 3315 | 3232 | 2266 | 4350 |  | 930 | 264 | 1391 | 1238 |  | 199
CO₂ | 133 | 149 | 117 | 126 |  | 147 | 165 | 121 | 149 |  | 165 | 214 | 129 | 140 |  | 162 | 200 | 131 | 146 |  | 132 | 149 | 113 | 125 |  | 167
PN ×10¹¹ | 22 | 28 | 15 | 22 |  | 25 | 28 | 16 | 30 |  | 37 | 56 | 25 | 27 |  | 31 | 43 | 21 | 28 |  | 21 | 22 | 14 | 22 |  | 27

GV5

| RDE-1 |  | RDE-2 |  | RDE-1-Dyn |  | RDE-2-Dyn |  | City-MW |  | Hill
| C. | U. | R. | MW |  | C. | U. | R. | MW |  | C.* | U. | R. | MW. |  | C. | U. | R. | MW. |  | C. | U. | R. | MW. |  | C./Urb
NOx | 13 | 17 | 10 | 12 |  | 9 | 18 | 2 | 4 |  | 23 | 44 | 15 | 5 |  | 17 | 33 | 13 | 3 |  | 5 | 10 | 3 | 3 |  |
NO₂ | 0 | 0 | 0 | 0 |  | 1 | 2 | 1 | 1 |  | 2 | 2 | 1 | 2 |  | 1 | 2 | 1 | 1 |  | 1 | 1 | 0 | 1 |  |
CO | 257 | 137 | 146 | 561 |  | 376 | 77 | 113 | 970 |  | 1078 | 364 | 752 | 2425 |  | 650 | 439 | 301 | 1200 |  | 108 | 55 | 56 | 145 |  |
CO₂ | 151 | 184 | 116 | 143 |  | 157 | 191 | 118 | 149 |  | 172 | 217 | 136 | 155 |  | 164 | 208 | 127 | 154 |  | 140 | 162 | 114 | 134 |  |
PN ×10¹¹ | 1 | 0.1 | 0.8 | 0.8 |  | 0.8 | 1.2 | 0.6 | 0.6 |  | 1.3 | 1.7 | 1.2 | 1.1 |  | 1.1 | 1.4 | 1.0 | 1.0 |  | 1.0 | 1.3 | 1.0 | 0.8 |  |

GV6

| RDE-1 |  | RDE-2 |  | RDE-1-Dyn |  | RDE-2-Dyn |  | City-MW |  | Hill
| C. | U. | R. | MW |  | C. | U. | R. | MW |  | C. | U. | R. | MW. |  | C. | U. | R. | MW. |  | C. | U. | R. | MW. |  | C./Urb
NOx | 20 | 21 | 5 | 35 |  | 22 | 48 | 7 | 5 |  | 16 | 33 | 5 | 4 |  | 16 | 38 | 2 | 5 |  |  |  |  |  |  |
NO₂ | 0 | 0 | 0 | 0 |  | 0 | 0 | 0 | 0 |  | 0 | 0 | 0 | 0 |  | 0 | 0 | 0 | 0 |  |  |  |  |  |  |
CO | 1050 | 973 | 524 | 1739 |  | 925 | 455 | 569 | 1764 |  | 8601 | 8245 | 5237 | 12837 |  | 6501 | 6309 | 4580 | 8472 |  |  |  |  |  |  |
CO₂ | 214 | 273 | 173 | 174 |  | 188 | 217 | 146 | 192 |  | 222 | 281 | 173 | 197 |  | 208 | 256 | 161 | 199 |  |  |  |  |  |  |
PN ×10¹¹ | 18 | 18 | 11 | 25 |  | 24 | 32 | 16 | 21 |  | 110 | 130 | 79 | 110 |  | 97 | 120 | 67 | 98 |  |  |  |  |  |  |

GV7

| RDE-1 |  | RDE-2 |  | RDE-1-Dyn |  | RDE-2-Dyn |  | City-MW |  | Hill
| C. | U. | R. | MW |  | C. | U. | R. | MW |  | C. | U. | R. | MW. |  | C. | U. | R. | MW. |  | C. | U. | R. | MW. |  | C./Urb
NOx | 60 | 101 | 37 | 27 |  | 31 | 52 | 13 | 18 |  | 113 | 195 | 72 | 51 |  | 70 | 143 | 37 | 21 |  | 18 | 31 | 50 | 7 |  | 25
NO₂ | 1 | 1 | 1 | 0 |  | 0 | 0 | 0 | 0 |  | 4 | 4 | 3 | 5 |  | 0 | 0 | 0 | 0 |  | 0 | 0 | 0 | 0 |  | 0
CO | 252 | 80 | 102 | 660 |  | 614 | 76 | 21 | 1751 |  | 3971 | 2125 | 4840 | 5436 |  | 2635 | 2961 | 3610 | 1500 |  | 307 | 102 | 346 | 412 |  | 127
CO₂ | 164 | 206 | 132 | 138 |  | 167 | 211 | 122 | 147 |  | 179 | 236 | 133 | 155 |  | 181 | 253 | 133 | 147 |  | 154 | 191 | 131 | 137 |  | 186
PN ×10¹¹ | 27 | 33 | 17 | 32 |  | 34 | 31 | 12 | 54 |  | 67 | 81 | 54 | 64 |  | 57 | 89 | 39 | 39 |  | 18 | 20 | 15 | 17 |  | 19

GV8

| RDE-1 |  | RDE-2 |  | RDE-1-Dyn |  | RDE-2-Dyn |  | City-MW |  | Hill
| C. | U. | R. | MW |  | C. | U. | R. | MW |  | C.* | U. | R. | MW. |  | C. | U. | R. | MW. |  | C. | U. | R. | MW. |  | C./Urb
NOx | 24 | 34 | 11 | 24 |  | 15 | 25 | 3 | 14 |  | 205 | 251 | 314 | 25 |  | 25 | 32 | 14 | 26 |  | 16 | 25 | 11 | 12 |  | 18
NO₂ | 2 | 2 | 1 | 1 |  | 1 | 2 | 1 | 1 |  | 12 | 16 | 16 | 3 |  | 2 | 2 | 1 | 2 |  | 2 | 2 | 1 | 2 |  | 3
CO | 189 | 41 | 83 | 520 |  | 133 | 26 | 17 | 353 |  | 2408 | 1118 | 2861 | 3625 |  | 3065 | 766 | 2422 | 6102 |  | 181 | 23 | 17 | 294 |  | 149
CO₂ | 173 | 210 | 135 | 162 |  | 170 | 188 | 135 | 178 |  | 179 | 214 | 145 | 170 |  | 189 | 223 | 156 | 183 |  | 158 | 167 | 132 | 160 |  | 182
PN ×10¹¹ | 0.2 | 0.2 | 0.1 | 0.2 |  | 0.2 | 0.2 | 0.1 | 0.2 |  | 0.2 | 0.3 | 0.2 | 0.2 |  | 0.4 | 0.4 | 0.3 | 0.5 |  | 0.1 | 0.1 | 0.1 | 0.2 |  | 0.1

*During a second repetition of the same dynamic test the emissions factors for the complete test were: NOx 23mg/km, NO₂ 2mg/km, CO 3973mg/km, CO₂ 190g/km, PN 5×10¹⁰ #/km

CNG-LCV

| RDE-1 |  | RDE-2 |  | RDE-1-Dyn |  | RDE-2-Dyn |  | City-MW |  | Hill
| C. | U. | R. | MW |  | C. | U. | R. | MW |  | C. | U. | R. | MW. |  | C. | U. | R. | MW. |  | C. | U. | R. | MW. |  | C./Urb
NOx | 308 | 641 | 123 | 42 |  | 354 | 702 | 253 | 47 |  | 852 | 1718 | 527 | 89 |  | 1060 | 1673 | 1052 | 307 |  | 242 | 659 | 178 | 51 |  | 515
NO₂ | 15 | 23 | 9 | 9 |  | 15 | 26 | 11 | 7 |  | 27 | 55 | 13 | 6 |  | 39 | 63 | 34 | 12 |  | 16 | 32 | 11 | 9 |  | 21
CO | 369 | 270 | 274 | 612 |  | 245 | 111 | 155 | 478 |  | 187 | 123 | 119 | 349 |  | 230 | 195 | 203 | 298 |  | 440 | 150 | 203 | 635 |  | 317
CO₂ | 256 | 296 | 211 | 249 |  | 231 | 277 | 181 | 223 |  | 287 | 342 | 240 | 269 |  | 277 | 323 | 227 | 267 |  | 251 | 277 | 206 | 248 |  | 251
PN ×10¹¹ | 11 | 26 | 0.6 | 0.2 |  | 1.6 | 3.7 | 0.4 | 0.3 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |