1.A.3.b i - iv - Emissions from fuel combustion in Road Vehicles (OVERVIEW)

Short description

This overview chapter provides information on the emissions from fuel combustion activities in road transport sub-categories 1.A.3.b i, ii, iii, and iv.

NFR-Code Name of Category
1.A.3.b i Passenger Cars
1.A.3.b ii Light Duty Vehicles
1.A.3.b iii Heavy Duty Vehicles
1.A.3.b iv Mopeds & Motorcycles


Activity data

Basically, total inland fuel deliveries are available from the National Energy Balances (NEBs) (AGEB, 2020) 1), line 62: Straßenverkehr (Road Transport) as compiled by the Association of the German Petroleum Industry (MWV) 2).

Based upon these primary activity data, specific consumption data for the different types of road vehicles are generated within TREMOD 3).

For further details see main chapter 1.A.3.b - Road Transport as wells as the sub-category chapters linked above.

Emission factors

The majority of emissions factors for exhaust emissions from road transport are taken from the 'Handbook Emission Factors for Road Transport' (HBEFA, version 4.1) 4) where they are provided on a tier3 level mostly and processed within the TREMOD software used by the party 5).

With respect to the emission factors applied for particulate matter, given the circumstances during test-bench measurements, condensables are most likely included at least partly. 1)

As it is not possible to present these tier3 values in a comprehendible way, the NFR sub-chapters linked above provide sets of fuel-specific implied emission factors instead.

For heavy-metal (other then lead from leaded gasoline) and PAH exhaust-emissions, default emission factors from (EMEP/EEA, 2019) 6) have been applied. Regarding PCDD/F, tier1 EF from (Rentz et al., 2008) 7) are used instead.

For information on the emission factors for heavy-metal and POP exhaust emissions, please refer to Appendix 2.3 - Heavy Metal (HM) exhaust emissions from mobile sources and Appendix 2.4 - Persistent Organic Pollutant (POP) exhaust emissions from mobile sources.

For ammonia emissions, the increasing use of catalytic converters in gasoline driven cars in the 1990s lead to a steep increase whereas both the technical development of the converters and the ongoing shift from gasoline to diesel cars resulted in decreasing emissions in the following years.

The observed trends for NO,,x,,, NMVOC and CO emissions represent the changes in legislatory emission limits and the regarding implementation of mitigation technologies.

Trends for sulphur dioxide show charcteristics very different from those shown above. Here, the strong dependence on increasing fuel qualities leads to an cascaded downward trend of SO,,2,, emissions, influenced only slightly by increases in fuel consumption and mileage.

The following table provides the development of sulphur contents over the years for Old (OGL) and New German Länder (NGL) and Germany (GER).

Table 1: Development of fuel sulphur contents in Germany

Area covered Year(s) covered Gasoline Diesel oil
EAST GERMANY (DDR) until 1988 500 ppm 6,000 ppm
1989-1990 500 ppm 6,000 ppm
WEST GERMANY (BRD) until 1984 250 ppm 2,700 ppm
1985 2,500 ppm
1986 2,100 ppm
1988 1,700 ppm
1990 220 ppm
GERMANY 1991 220 ppm 1,300 ppm
1995 180 ppm
1996 600 ppm
1997 400 ppm
1998-2000 70 ppm 300 ppm
2001 55 ppm 250 ppm
2002 25 ppm 40 ppm
since 2003 8 ppm 8 ppm

For exhaust particulate matter emissions from diesel road vehicles, the party assumes that nearly all particles emitted are within the PM,,2.5,, range, resulting in similar emission values for PM,,2.5,,, PM,,10,,, and TSP. Excumptions from this assumption can be observed for gasoline road vehicles for the years until 1997 when additional TSP emissions resulted from the use of leaded gasoline that was banned in 1997. Furthermore, black carbon emissions are estimated via implied emission factors derived from fractions of PM as provided in 8).

For Heavy Metals and PAHs, emissions are calculated with tier1 default EF from 9) resulting in trends that simply reflect the annual fuel consumption. Here, the only excumption are lead emissions from leaded gasoline that was in use until 1996 with lead contents provided in the table below:

Table 2: Development of gasoline's lead content in Germany

Area covered Year(s) covered Lead content
EAST GERMANY (GDR) 1989-1990 126 mg/l
WEST GERMANY (BRD) 1990 42 mg/l
GERMANY 1991 29 mg/l
1992 20 mg/l
1993 16 mg/l
1994 11 mg/l
1995 8 mg/l
1996 4 mg/l
since 1997 0 mg/l (banned)


Recalculations of exhaust-emissions are mainly based on annual routine revisions of the underlying TREMOD model. For more information, please see the specific chapters linked above.

1) AGEB (2020): Working Group on Energy Balances (Arbeitsgemeinschaft Energiebilanzen (Hrsg.), AGEB): Energiebilanz für die Bundesrepublik Deutschland; URL: https://ag-energiebilanzen.de/7-0-Bilanzen-1990-2018.html, Köln & Berlin, 2020.
2) MWV (2020): Association of the German Petroleum Industry (Mineralölwirtschaftsverband, MWV): Annual Report 2018, page 65, Table 'Sektoraler Verbrauch von Dieselkraftstoff 2012-2018'; URL: https://www.mwv.de/wp-content/uploads/2020/09/MWV_Mineraloelwirtschaftsverband-e.V.-Jahresbericht-2020-Webversion.pdf, Berlin, 2020.
3), 5) Knörr et al. (2020a): Knörr, W., Heidt, C., Gores, S., & Bergk, F.: ifeu Institute for Energy and Environmental Research (Institut für Energie- und Umweltforschung Heidelberg gGmbH, ifeu): Fortschreibung des Daten- und Rechenmodells: Energieverbrauch und Schadstoffemissionen des motorisierten Verkehrs in Deutschland 1960-2035, sowie TREMOD, im Auftrag des Umweltbundesamtes, Heidelberg & Berlin, 2020.
4) Keller et al. (2017): Keller, M., Hausberger, S., Matzer, C., Wüthrich, P., & Notter, B.: Handbook Emission Factors for Road Transport, version 4.1 (Handbuch Emissionsfaktoren des Straßenverkehrs 4.1) URL: http://www.hbefa.net/e/index.html - Dokumentation, Bern, 2017.
6), 8), 9) EMEP/EEA, 2019: EMEP/EEA air pollutant emission inventory guidebook 2019; https://www.eea.europa.eu/publications/emep-eea-guidebook-2019/part-b-sectoral-guidance-chapters/1-energy/1-a-combustion/1-a-3-b-i/view; Copenhagen, 2019.
7) Rentz et al., 2008: Nationaler Durchführungsplan unter dem Stockholmer Abkommen zu persistenten organischen Schadstoffen (POPs), im Auftrag des Umweltbundesamtes, FKZ 205 67 444, UBA Texte | 01/2008, January 2008 - URL: http://www.umweltbundesamt.de/en/publikationen/nationaler-durchfuehrungsplan-unter-stockholmer
During test-bench measurements, temperatures are likely to be significantly higher than under real-world conditions, thus reducing condensation. On the contrary, smaller dillution (higher number of primary particles acting as condensation germs) together with higher pressures increase the likeliness of condensation. So over-all condensables are very likely to occur but different to real-world conditions.