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Transport Emissions

Working Group 3.44


Mobility has tremendous economic significance: With a labor force of 800 000, the German automotive industry had a record turnover of 426 bn euros in 2017. The four largest automotive suppliers achieved additional turnover of 137 bn euros – which corresponds to 7.7 % of overall economic performance in Germany.

Motor vehicles are the most commonly used means of transport for passenger transportation (> 80 % of the transport capacity in 2010), whereas trucks (light- and heavy-duty vehicles – L+HDVs) are the primary means of transport for goods transportation (75 % of the haulage capacity in 2011). The vast majority of vehicles rely on combustion engines.

Within the EU, mobility-related emissions remain the second largest source (25 %) of greenhouse gases despite all progress achieved in optimizing combustion engines.

A continuous tightening of the requirements placed on emission limit values is expected both at the European level and at the national level within the next few years. Topical examples of these tightened requirements in Germany include reducing the PTI limit values for EUR 6/VI vehicles for CO and opacity by 50 % and introducing soot particle number limits in periodic exhaust emission tests (Abgasuntersuchung – AU) as of 2021. For example, in the European Union, the fleet limit values for CO2 have been reduced, and new testing cycles and conditions have been introduced for the vehicle type approval (WLTP – Worldwide harmonized Light vehicles Test Procedure) and for RDE (Real Driving Emissions).

The tightened requirements placed on the limit values make the required exhaust gas measuring techniques and exhaust gas sampling increasingly complex, as well as the whole testing infrastructure. Consequently, the importance of metrologically validating the measurements is increasing.

This is the set of interlinked problems that Working Group 3.44, Transport Emissions, works on. Our working group maintains its focus on application and demand when dealing with the following topics:

  • metrological traceability of measurands from the field of transport emissions;
  • development of the national and international traceability structures of transport-related emissions; and
  • development and provision of service offers with respect to the testing, calibration and certification of measuring instruments used in the field of transport emissions.


Our working group is a committed and active member of various national and international committees, including:

  • AUPNAg – National working group for the introduction of a particle-counting technique into German PTI emissions tests (AU) and general inspection (HU), managed by PTB (S. Pratzler) together with the Federal Highway Research Institute (BASt – Bundesanstalt für Straßenwesen)
  • AGME – Working Committee on "Exhaust meters"
  • DIN NA 062-05-73 AA – DIN Standards Committee Materials Testing on "Gas analysis and gas quality"
  • DIN NA 052-00-34-53 AK – DIN Standards Committee Road Vehicle Engineering "Performance assessment of the Portable Emission Measuring Systems (PEMS)"
  • CEN TC 301/WG 16 “Performance assessment of Portable Emission Measuring Systems (PEMS)”
  • OIML TC 16/ SC1 “Air pollution”
  • OIML TC 16/SC 1 "Development of a new Recommendation on Instruments for measuring the vehicle exhaust soot particle number (PN)” (convener PTB (V. Ebert), together with NMI+/NL)
  • Implementing the working group's topics in CCQM-GAWG and Euramet TC-MC

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WG 3.44, "Transport Emissions", is mainly a service-oriented working group. For pure R&D topics, it relies on the research activities and results of its adjacent Working Groups, 3.42 and 3.43, as well as on the national standards these working groups supply.

  • WG 3.42, Spectrometric Gas Analysis

    • Analytical metrology of gaseous emissions such as CO, CO2, NOx, and NH3

  • WG 3.43, Aerosols and Particle Measurements

    • Preparative and analytical aerosol metrology

      • Primary traceability of aerosol analytical methods
      • Production/characterization of reference aerosols
      • Operating reference aerosol generators

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Testing, Calibrating and Certification

  • Type examination of 4- and 5-gas exhaust analyzers

    • in accordance with Annex B of 2014/32/EU (MID)

  • Type examination of partial-flow opacimeters

    • in accordance with Module B of the Measures and Verification Ordinance (MessEV), and
    • traceability of the reference standards of the verification boards (Eichdirektionen) to PTB's primary standards for the testing of partial-flow opacimeters

  • Type examination of particle counters

    • in accordance with Module B of the Measures and Verification Ordinance (MessEV)

  • Calibrating of particle counters



  • Contact persons for issues regarding the traceable measurement of transport emissions
  • Information concerning conformity assessment procedures and corresponding legal requirements
  • Metrological consultation and assessment provided to verification authorities with regard to emission-relevant measurands of the calibration authority and Confirmity Assessment Bodies
  • Appraisals and audits on behalf of DAkkS and of PTB's Conformity Assessment Body

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  • Conformity Assessment Body of PTB
    For general information about conformity assessment procedures, please visit the website of PTB's Conformity Assessment Body Opens external link in new windowLink
  • Measuring Instruments Directive
    Information on the conformity assessment of measuring instruments regulated at the European level, such as 4- or 5-gas exhaust gas analyzers Opens external link in new windowLink
  • Measures and Verification Ordinance
    Information concerning the conformity assessment of measuring instruments regulated at the national level, such as partial-flow opacimeters Opens external link in new windowLink
  • Welmec 7.2 Software Guide
    For information about the requirements placed on measuring instrument software, please visit the website of Working Group 8.51, Metrological Software Opens external link in new windowLink 
  • PTB-Requirements PTB-A 12.16 Particle Counter (05/2021)
    National requirements for particle counter used as part of emission tests for EUR 6/VI Diesel
    Opens external link in new windowlink

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