A Comparison of Light-duty Vehicle NOₓ Emissions Measured by Remote Sensing in Zurich and Europe

Nitrogen oxide (NOₓ) emissions cause air-quality problems and have adverse effects on public health. Diesel automobiles routinely exceed the laboratory-certified limits on NOₓ emissions. The negative impact of excess NOₓ emissions is particularly bad in Europe because of ineffective enforcement of emission standards and the increasing adoption of diesel fuel in the European light vehicle fleet. Remote sensing (RS) is used to measure real-world NOₓ emissions in Europe. Emissions are measured remotely via spectroscopy as a vehicle drives by a roadside detector, making RS a nonintrusive method for emissions measurement. RS can measure the emissions from hundreds of vehicles in a single day. Many hundreds of such measurements for a given vehicle type can be collated at multiple locations. The results provide a realistic picture of the exhaust emissions of that vehicle type over time and under different operating conditions. Switzerland’s Federal Office for the Environment financed in 2016 a project to pool data from RS operations in France, Spain, Sweden, Switzerland, and the United Kingdom between 2011 and 2017 in a single database, CONOX. The CONOX data were used to quantify real-world NOₓ emissions of automobiles in Europe, with the results confirming significant emission excess for most diesel automobiles. Data from the Canton of Zurich accounted for more than one-third of light vehicle measurements in the CONOX dataset. The Zurich RS data are unique in several ways. First, RS operations have been conducted in Zurich at the same sites and the same season each year since 2000. Because the Zurich campaigns are conducted at regular intervals and under consistent driving conditions, the time series enables the monitoring of vehicle emissions over time. Second, the road at the main measurement site is much steeper than at all other measurement sites in CONOX. The steeper road gradient results in a higher average estimated engine load in the Zurich data than in data from elsewhere. The authors compare the RS emissions measurements in Zurich to the rest of the CONOX database, focusing on the effect of engine load on NOₓ emissions.


  • English

Media Info

  • Media Type: Digital/other
  • Edition: Consulting Report
  • Features: Appendices; Figures; References; Tables;
  • Pagination: 29p

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Filing Info

  • Accession Number: 01716823
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jul 16 2019 12:02PM