Blog: Tests get stricter but emissions dirty word

More real-wrold emission tests for harmful nitrogen oxides are being introduced next year.

More real-wrold emission tests for harmful nitrogen oxides are being introduced next year. - Credit: supplied

The 'dieselgate' emissions scandal has been bad news for Volkswagen but it's brought the hazards of nitrogen oxides to people's attention, says motoring editor Andy Russell.

If the emissions scandal cloud can have a silver lining it's that the world has woken up to nitrogen oxides (NOx) and not just carbon dioxide (CO2).

Diesel cars may have low CO2 emissions but the downside is high levels of NOx which, particularly in traffic-heavy built-up areas, causes breathing problems, can worsen the effects of asthma and bronchitis, aggravate heart disease and causes acid rain.

Many people's awareness of NOX has been as invisible as the emissions themselves so it's good news that a new system to help people understand them is set to launch early next year.

The initiative, set up by Emissions Analytics, will inform consumers, policy-makers and manufacturers about the real-world emissions from new cars. An accreditation system will enable buyers to make informed purchasing decisions based on how much pollution is being emitted by new cars.

Manufacturers will be able to demonstrate the effectiveness of their pollution reduction technology, while policy-makers will be able to monitor the progressive improvement of air quality. This will be a European Union-wide project and is designed to work with the Real Driving Emissions (RDE) regulations for new vehicles which come into force next month, initially for monitoring purposes.

It will be a big step in preventing another 'dieselgate' scandal when millions of Volkswagen Group cars were found to have used 'defeat devices' to hoodwink emissions tests by detecting when the cars were in laboratory conditions and so tune the engines to run cleaner – but likely with reduced performance – during the test.

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Members of the European Commission's technical committee of motor vehicles voted by a large majority on the second package of implementing measures to introduce RDE tests for air pollutant emissions by diesel cars as laboratory tests do not accurately reflect the amount of air pollution emitted on the road. From September 1, 2017 these RDE tests will determine whether all newly-approved types of vehicles are allowed to be put on the market. From September 2019 it will apply to all new vehicles.

And car-makers must also reduce the divergence between the regulatory limit tested in laboratory conditions and the values when the car is driven by a real driver on a real road – the 'conformity factor'. The current Euro 6 NOx limit for diesels is 80mg/km – the discrepancy in real driving conditions compared to laboratory testing is 400% on average.

In a first step, they will have to cut the conformity factor to a maximum 2.1 (110%) for new models by September 2017 (new vehicles by September 2019). The second step is to bring it down to 1.5 (50%) by January 2020 for all new models (January 2021 for all new vehicles).

A shame then that the RAC Report on Motoring 2015 found just 19% of British motorists saying they would consider a hybrid or electric vehicle as their next car. And 47% of them said potentially lower running costs – rather than cutting emissions – was the main attraction.

The RAC warns changes to vehicle excise duty (VED) are likely to dampen enthusiasm for such vehicles. Cars producing up to 100g/km of CO2 are currently exempt from the tax but from 2017 only new cars with zero emissions will avoid VED. This means lower-emission models will pay between £10 and £100 in the first year and then the standard annual rate of £140.

So, on the one hand, we are going to have a more accurate idea of how polluting our cars really are but, on the other, many drivers don't seem to care.

The reality is we can't afford not to care – if we don't go down the cleaner motoring route, with clearer information, running a car might just become too taxing for many of us.

What do you think? Email motoring@archant.co.uk