The European Parliament’s environment committee has rejected proposed new EU standards for diesel car emissions, arguing that they are not strict enough.

The MEPs approved a resolution saying that the proposal to raise diesel car emission limits for nitrogen oxides (NOx) by up to 110% as part of the introduction of the Real Driving Emissions (RDE) test procedure, "was neither explained nor justified", and would undermine the enforcement of existing EU standards. The Parliament has a right to veto the proposal.

The new RDE procedure is designed to allow for a more realistic testing of car emissions, by using a portable device and performing the test on the road. The current laboratory-based procedure suffers from a number of loopholes, which are exploited by carmakers to brand their products as cleaner than they really are.

In a draft act endorsed by member states in the Technical Committee for Motor Vehicles (TCMV) on 28 October, the European Commission proposed, as part of a package of measures setting up the RDE test procedure, to raise the maximum car NOx emission limits by up to 110%. It justified this by referring to the need to take account of technical uncertainties to do with the use of the new Portable Emission Measurement Systems (PEMS) device.

However, MEPs point out that the Commission itself concluded, on the basis of an analysis by the Joint Research Centre (JRC), that the maximum margin of measurement error with this device is 30%, and on average 18.75%.

The committee opposed the adoption of the measure, also stressing that:

• air pollution causes over 430,000 premature deaths in the EU every year and costs up to an estimated €940bn per year as a result of its health impacts;

• nitrogen oxides (NOx) are major air pollutants which cause lung cancer, asthma and many respiratory diseases, as well as environmental degradation such as eutrophication and acidification;

• diesel vehicle exhausts are a principal source of NOx in urban areas in Europe; and

• recent air pollution analyses by the European Environment Agency attribute 75,000 premature deaths to NO2 emissions in Europe, with 93% of all exceedances occurring close to roads.

The issue will now be put to a vote by the full Parliament at the 18-21 January plenary session in Strasbourg.