There is now more information available to tell you how clean new cars are, both for the harmful pollutants that immediately affect the air we breathe, and for carbon dioxide (CO2) which has a longer term impact on the climate. But where can you find more information about the specific model you are interested in?

With the introduction of a new testing regime, real-world particulate (as particle number or PN) and nitrogen oxides (NOx) emissions data have to be published for all new cars from September 2019 onwards. Car buyers can obtain this information through official documents (brochures or specifications) produced by the car manufacturer, or available from the car dealership. Emissions information is also published via the European Automobile Manufacturers Association (ACEA), although not in a form that is intended for consumers.

New diesel vehicles certified to the Euro 6d-temp standard are the first to be seen as having low emissions – reflecting the emissions standards that have been set for driving in real-world conditions.

Although certification is only based on these official figures, other sources of information may make it easier to understand the data and make comparisons between vehicles.

Launched in February 2019, the Green NCAP is run by the same independent organisation that has provided Euro NCAP vehicle safety information for over 20 years. Its database will become more populated over time, although initially it only contained data for 12 cars. It uses the same five-star rating system adopted for grading safety tests. ‘Clean Air’ and ‘Energy Efficiency’ are measured separately, and the Green NCAP headline ‘star’ rating then combines them into a single score. Because it is so far only looking at the tailpipe, the database favours electric and hybrid vehicles. It is therefore important to look at the individual Clean Air score if you want to check the pollutant emissions.

The Green NCAP for instance highlights that modern diesels, complying with the latest Euro 6d-temp standard, have a better Clean Air index than older models (as shown below) and therefore benefit from a higher star ranking overall. In fact, the only non-hybrid or non-electric vehicles that have achieved any stars are those with Euro 6d-temp certification. Laboratory test cycles have been extended to cover a wider, ‘more realistic’ range of conditions than the standard certification cycle, providing additional reassurance to potential car buyers. On-road tests to check Real-Driving Emissions (RDE) have also been made more challenging, again with the intention of giving confidence to consumers that a car will perform in any conditions.

Source: Green NCAP

Car buyers are now able to make more informed decisions, thanks to the availability and transparency of official emissions test results, and independent sources releasing real-world performance data and rankings.

The AIR (Allow Independent Road-testing) Index is another ranking scheme produced by an independent organisation, the AIR Alliance, whose members have been testing cars in real-world conditions for several years.  The AIR Index rates cars from A (dark green), the best, down to E (red), the worst, based on their on-road urban NOx emissions. Vehicles are all tested using a single route for directly comparing their impact on air quality. However, since there is not the capacity to test all newly released car models, the particular model you are looking for might not appear on the database yet. However, car buyers should not make a decision based on some information they find about older vehicles. For instance, a 2014 model with ‘poor’ emissions is likely to be completely different from a 2019 model with a much better performance, as the technology controlling emissions is very different for the later version.

Older emissions data may however still be useful for consumers looking to buy a second-hand car and wanting to know the emissions levels of their current car.

Source: Air Index

Several other organisations also carry out emissions tests to determine how different vehicles perform in real world conditions. For instance, Emissions Analytics (a founder member of the AIR Alliance) feeds the data into its EQUA Index, providing information on CO2 emissions, fuel economy and air quality. This is also related to the European emissions standards.

ADAC, the German mobility organisation, carries out its own testing which confirms that cars of the most recent Euro 6d-temp standard emit very low levels of pollutants in the real world. It also provides a useful list (in German) of cars that are already certified to the latest emission standards.

Ultimately, since it is the responsibility of vehicle manufacturers to provide information about emissions level and car performance, the best place to find what you need is the car dealership. Dealers have historically seen ‘emissions’ as CO2 only, but are now more knowledgeable about tailpipe pollutants, especially NOx and PN.

There is still some way to go, but what is certain is that car buyers are now able to make a more informed decision about their purchases, thanks not only to the greater availability and transparency of official emissions test results but also to independent sources releasing real-world performance and rankings to supplement the official data.

© Delphi

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