Diesel engine emissions: are they no longer tolerable?

  • Helmut GreimEmail author
Review Article


Emissions from diesel engines contain several hundred chemical compounds, which are emitted partly as gas and partly as particles. The composition of diesel exhaust and its concentrations in air has changed significantly over time, to the extent that now there is a distinction between “traditional” and “new technology” diesel emissions. New technology diesel engines comply with emissions from EURO 3 vehicles and higher. Starting with EURO 5, a significant further reduction of particle emissions has been achieved by increased temperature, which, however, lead to increased emissions of NOx and exceeded the NO2 emission limit. To overcome this problem, some car manufacturers installed illegal software that detected the vehicle test bench operation, resulting in low emissions during the test cycle. Detection of such devices in 2015 led to the “Diesel scandal”. In 2017 the worldwide harmonized light vehicles test procedure (WLTP) was introduced for new cars, which simulates emissions under different driving conditions. It became mandatory for certification of all new vehicles by September 2018. In addition, fleet CO2 emissions have been introduced for all cars, requiring that by 2020 95% of each manufacturer’s passenger car must meet the CO2 emission target of 95 mg/km, and by 2021 100% of the fleet. All these regulations significantly reduced the emissions of diesel- and gasoline-driven cars, which since the introduction of the EURO 6 regulation in 2014 are almost similar for both. Since the energy efficiency of diesel motors is up to 20% higher than that of gasoline-driven cars resulting in up to 20% lower CO2 emission, there is no reason to question the future use of diesel engines. These regulations apply for new cars. However, air concentrations at sampling points close to streets with high traffic still exceed the limit values especially for NO2. In several cities this led to restrictions for passenger cars of EURO 5 and below. Since concentrations close to streets are not relevant to evaluate the long-term exposure of the population, these measures are highly debatable.


Diesel engine emissions Limit values Modern Diesel technology Efficiency of Diesel engines Toxicological evaluations of emissions 



I gratefully acknowledge the assistance by Prof. Thomas Koch, Karlsruhe Institut für Technolgie to describe the modern after-treatment devices.

Compliance with ethical standards

Conflict if interest

The author declares that he has no conflict of interest.


  1. Boffetta P (2012) Re: the diesel exhaust in miners study: a nested case–control study of lung cancer and diesel exhaust and a cohort mortality study with emphasis on lung cancer. J Natl Cancer Inst 104:1842–1843CrossRefGoogle Scholar
  2. Crump KS, Van Landingham C, Moolgavkar SH, McClellan R (2015) Reanalysis of the DEMS nested case-control study of lung cancer and diesel exhaust: suitability for quantitative risk assessment. Risk Anal 35:676–700CrossRefGoogle Scholar
  3. Crump KS, Van Landingham S, McClellan RO (2016) Influence of alternative exposure estimates in the diesel exhaust miners study: diesel exhaust and lung cancer. Risk Anal 36:1803–1812CrossRefGoogle Scholar
  4. Greim H (ed) (2008) Diesel engine emissions, MAK value documentation. In: The MAK-collection for occupational health and safety, Wiley, Weinheim. Accessed 07 Mar 2019
  5. Hallberg LM, Parks J, Hernandez C, Ward JB, Ameredes BT, Norton C, Zaas S, and Wickliffe JK (2014) Genotoxicity of diesel exhaust from 2007-compliant diesel engines: final results of the 12- and 24-month exposures of rats from the aces study. Health Effects Institute 2014 Annual Conference May 4–6, 2014, Alexandria, VA, USA.
  6. Heinrich U, Fuhst R, Rittinghausen S, Creutzenberg O, Bellmann B, Koch W, Levsen K (1995) Chronic inhalation exposure of Wistar rats and two different stains of mice to Diesel engine exhaust, carbon black and titanium dioxide. Inhal Toxicol 7:533–556CrossRefGoogle Scholar
  7. Henschler (ed) (1987) Diesel engine emissions, MAK Value Documentation (English version: 1990). In: The MAK collection for occupational health and safety, VCH, Weinheim. Accessed 07 Mar 2019
  8. Hesterberg TW, Long CM, Bunn WB, Lapin CA, McClellan RO, Valberg PA (2012) Health effects research and regulation of Diesel exhausT: an historical overview focused on lung cancer risk. Inhal Toxicol 24(Suppl 1):1–45. CrossRefGoogle Scholar
  9. IARC (2014) Diesel and gasoline engine exhausts. In: Diesel and gasoline engine exhausts and some nitroarenes, IARC monographs on the evaluation of carcinogenic risk of chemicals to humans, vol 105, International Agency for Research on Cancer, Lyon, pp 39–486. Accessed 07 Mar 2019
  10. IARC, International Agency for the Research on Cancer (1989) Diesel and gasoline engine exhausts. In: Diesel and gasoline engine exhausts and some nitroarenes. IARC monographs on the evaluation of carcinogenic risk of chemicals to humans, vol 46, International Agency for Research on Cancer, Lyon, pp 41–185. Accessed 07 Mar 2019
  11. Liang F, Lu M, Keener TC, Liu Z, Khnag FJ (2005) The organic composition of Diesel particulate matter, Diesel fuel and engine oil of non-road Diesel generator. J Environ Monit 7:983–988CrossRefGoogle Scholar
  12. Mauderly JL, Jones RK, Griffith WC, Henderson RF, McClellan RO (1987) Diesel exhaust is a pulmonary carcinogen in rats exposed chronically by inhalation. Fundam Appl Toxicol 9:208–221CrossRefGoogle Scholar
  13. McClellan R (2012) Re: the diesel exhaust miners study: a nested case-control of lung cancer and diesel exhaust, a cohort mortality study with emphasis on lung cancer, and the problem with diesel. J Natl Cancer Inst 104:1843–1845CrossRefGoogle Scholar
  14. McDonald JD, Doyle-Eisele M, Seagrave J, Gigliotti AP, Chow J, Zielinska B, Mauderly JL, Seilkop SK, Miller RA, HEI Health Review Committee (2015) Part 1. Assessment of carcinogenicity and biologic responses in rats after lifetime inhalation of new-technology diesel exhaust in the ACES bioassay. Res Rep Health Eff Inst 184:9–44 (discussion 141-71) Google Scholar
  15. Möhner M (2016) The hidden impact of healthy-worker effect on the results of the diesel exhaust in miners study. Eur J Epidemiol 31:803–804CrossRefGoogle Scholar
  16. Möhner M (2019) The mortality risk of nitrogen dioxide: a critical evaluation from an epidemiological-statistical perspective. Arbeitsmed Sozialmed Umweltmed 54:394–396Google Scholar
  17. Möhner M, Wendt A (2017) A critical review of the relationship between occupational exposure to diesel emissions and lung cancer risk. Crit Rev Toxicol 47:185–224CrossRefGoogle Scholar
  18. Möhner M, Kersten N, Gellissen J (2013) Diesel motor exhaust and lung cancer mortality: reanalysis of a cohort study in potash miners. Eur J Epidemiol 28:159–168CrossRefGoogle Scholar
  19. Morfeld P (2012) Diesel exhaust in miners study: how to understand the findings? J Occup Med Toxicol 7:10–15CrossRefGoogle Scholar
  20. NEG/DECOS, Nordic Expert Group/Dutch Expert Committee on Occupational Safety (2016) 149. Diesel engine exhaust. Taxell P, Santonen T, The Nordic Expert Group for criteria documentation of health risks from chemicals and the Dutch Expert Committee on occupational safety. Arbete och Hälsa, vol 49(6)Google Scholar
  21. NIST (US National Institutes of Standards and Technology) (2006) Diesel Particulate Matter. Material Details. Accessed 07 Mar 2019
  22. SCOEL, Scientific Committee on Occupational Exposure Limits (2016) Diesel engine exhausts. Greim H, Hartwig A, Heederik D, Levy L, Pospischil E, Santonen T, Van Tongeren M, Papameletiou D, Klein CL, SCOEL/Opin/403, Opinion from the Scientific Committee on Occupational Exposure Limits. European Commission, Brussels. Accessed 07 Mar 2019
  23. Silverman DT, Attfield MD (2012) Response. J Natl Cancer Inst 104:1848–1849CrossRefGoogle Scholar
  24. Silverman DT, Samanic CM, Lubin JH, Blair AE, Stewart PA, Vermeulen R, Coble JB, Rothman N, Schleiff PL, Travis WD, Ziegler RG, Wacholder S, Attfield MD (2012) The diesel exhaust in miners study: a nested case-control study of lung cancer and diesel exhaust. J Natl Cancer Inst 104:1–14Google Scholar
  25. Silverman DT, Lubin JH, Blair AE, Vermeulen R, Stewart PA, Schleiff PL, Attfield MD (2014) RE: the diesel exhaust in miners study (DEMS): A nested case control study of lung cancer and diesel exhaust. J Natl Cancer Inst 106:1–3CrossRefGoogle Scholar
  26. Umweltbundesamt (2018) Umweltbundesamt: 2018_02_14_em_entwicklung_in_d_trendtabelle_luft_v1.0.xlsx Trend SummaryGoogle Scholar
  27. US EPA (2003) IRIS, integrated risk information system. Diesel engine exhaust. Last revised 02/28/2003. Washington, DC, USA. Accessed 07 Mar 2019
  28. US EPA (2018) Federal register: review of the primary national ambient air quality standards for oxides of nitrogen. Rule by the Environmental Protection Agency on 04/18/2018. Accessed 07 Mar 2019
  29. US EPA (US Environmental Protection Agency) (2002) Health assessment document for diesel engine exhaust. EPA/600/8-90/057F. US Environmental Protection Agency, Washington, DC, USA. Accessed 07 Mar 2019
  30. WHO (1996) Diesel fuel and exhaust emissions. World Health Organization, GenevaGoogle Scholar
  31. WHO (2006) WHO air quality guidelines for particulate matter, ozone, nitrogen dioxide and sulfur dioxide—global update 2005. Accessed 07 Mar 2019
  32. WHO (2018) Ambient (outdoor) air quality and health. Fact Sheet, 2 May 2018. Accessed 07 Mar 2019

Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Technical University MunichMunichGermany

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