Diesels choking us with cheap, badly configured exhaust treatment
The use of cheap, ineffective or poorly configured exhaust treatment systems is one of main reasons why the majority of new diesel cars fail to meet EU air pollution limits on the road. That’s according to the latest research by the International Council on Clean Transportation (ICCT), which last year found that 13 out of 15 modern diesel cars did not achieve the Euro 6 limit in real-world testing.
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The news comes as Euro 6 auto emissions standard for all new cars sales takes effect – in theory – this month. In practice, the test methodology, dates for compliance and real-world limits have still to be agreed.
Striking differences were found between the aftertreatment systems featured in EU and US vehicles with the latter having better performing but also more complex and expensive systems in some models that otherwise use a single NOX control technology in their European market versions.
Carmakers are also failing to configure the best systems in a way that minimizes emissions. The cost of a modern diesel after-treatment system is around €300. The ICCT research shows the problem to be worse for smaller vehicles.
The European Commission and member states have signed off on new test procedures for diesel cars that will, for the first time, measure their ‘real world’ emissions under the Euro 6 standard. The new ‘real driving emissions’ (RDE) regime will see vehicles being taken out of the laboratories to be tested on roads.
T&E said the new RDE test must be quickly introduced to bring an end to ‘cycle beating’ techniques used by car manufacturers to attain emissions levels typically five times lower than actual air pollution emissions on the road for modern Euro 6 cars. Meanwhile, the car industry is trying to reopen the discussions through introducing new ‘transfer functions’ to normalise test results.
However, in a rare moment of cross-party consensus, MEPs last week warned that the introduction of the new tests should not weaken existing regulations through the backdoor. Some members of the European Parliament’s environment committee expressed concern that Euro 6 limits agreed in 2007 would be raised through the use of ‘conformity factors’. The Commission and national governments were set to agree within weeks what the limits for the RDE tests will be and from when they will apply. The new discussions concerning ‘transfer functions’ put this at risk.
The car industry’s response has been a misinformation campaign about diesel, which forced T&E to issue a special briefing, Five facts about diesel the car industry would rather not tell you. It responded to a website set up by a consortium of car manufacturers, suppliers and repairers that attempted to hide the fact that a typical new diesel car emits 10 times more nitrogen oxides than an equivalent gasoline car.
The current testing regime has seen nitrogen dioxide limits exceeded across Europe, exacerbating asthma in vulnerable people and shortening life expectancy in polluted places. In the UK, where the number of diesel cars has risen from 1.6 million to 12 million since 1994, a government health agency found that thousands of people suffered attacks when smog full of tiny particles and nitrogen dioxide (NO2) gas typical of diesel emissions descended last spring. Estimates of the number of premature deaths in London also doubled once nitrogen dioxide effects were incorporated into the analysis.