New data shows modern diesel emissions are comparable with petrol

According to the German mobility organisation ADAC (Allgemeiner Deutscher Automobil Club), modern diesel and petrol cars tested in real world conditions out-performed regulatory requirements.

Until September 2017, car emissions testing in Europe was limited to laboratory testing that did not fully represent the level of pollutant emissions from new car models. Car buyers therefore could not compare petrol and diesel models or makes due to insufficient reliable, publicly available data on realistic driving conditions.

Then, in September 2017, the European Commission started to implement new emissions testing procedures that combined improved laboratory tests and new emissions testing procedures based on real driving situations.

Thanks to the Real-Driving Emission (RDE) test and the Worldwide Light vehicle Test Procedure (WLTP), car buyers can check emissions levels of nitrogen oxides (NOx) and particulates for new vehicles on the market. In addition, from September 2019, car manufacturers are required to publish emissions testing results of all new cars certified as ‘Euro 6d-temp’, in conditions equivalent to driving in the real world as well as in the laboratory.

Some independent organisations are also making information available based on their own, similar test procedures. The German equivalent of the UK’s AA (Automobile Association), the ADAC, found that while the NOx emissions limits set out in the latest European legislation (Euro 6 standard) are not yet fuel-neutral and are higher for diesel than for petrol (80 mg/km as opposed to 60 mg/km), most diesel cars tested on the road are nevertheless well below the lower limit for petrol, as evidenced by the data outlined below:

Car emissions measured on the road | Source: ADAC

Car emissions measured on the road | Source: ADAC

A number of these tests were done at low temperatures (between 0 and 8°C), a range at which some cars have previously not met the limits. The fact that these modern diesel cars were able to comfortably achieve very low levels of NOx in a variety of conditions also highlights the improvements that have been made, even since the introduction of the first Euro 6 cars in 2016.

With modern diesel and petrol cars now performing similarly, as regulations intended, consumers can compare vehicles based on their needs, rather than on the level of emissions these cars generate.

There has been growing concern regarding the increase in overall CO2 emissions from cars, partly due to the increase in sales of heavier SUVs (sport utility vehicles), but also due to the decline in sales of diesel cars, which emit less CO2.

Whenever it makes economic and practical sense to the buyer, and if there is little or no difference in pollutant emissions (information should be available in vehicle brochures from your dealer or online), choosing a new diesel car will help bring down CO2 emissions levels in comparison with a petrol car’s performance – a ‘win-win’ for buyers and the climate.