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Pressrelease | 2023-05-26

Remote emission sensing campaign in Prague, Czech Republic.

Tests reveal widespread emissions cheating

Despite stricter regulations, many cars and trucks still emit too much nitrogen oxides and particulate matter. This is according to the IVL-led EU project CARES, which has carried out extensive vehicle exhaust emissions in European cities. The tests also show that many trucks have manipulated emission control systems – a phenomenon that increases at night.

CARES (City Air Remote Emission Sensing), which develops methods to monitor actual emissions of nitrogen oxides and particulate matter in traffic, has measured the exhaust emissions of more than 250,000 vehicles in Milan, Prague and Krakow – cities with major air quality problems, but also high ambitions to reduce traffic emissions, for example by introducing low emission zones in city centres.

“The issue of air quality and emissions control is high on the European Commission’s agenda. Many European cities have major problems meeting the guideline values for nitrogen oxides and particulate matter in the air, so it is important to measure in real traffic to see whether the existing rules are being followed or whether further action is required”, says Åke Sjödin, project coordinator and emissions expert at IVL.

The testing in CARES was conducted from the roadside and with instruments on board a following car, known as ‘plume chasing’. This provides a better understanding of how much different types of vehicles emit, and what problems exist. Ultimately, the aim of the studies is to use the test results to, for example, fine or restrict the driving of vehicles with excessive emissions.

One result of the tests is that almost 40 per cent of all trucks in Euro classes IV, V and VI had suspiciously high emissions of nitrogen oxides, or emitted more than the permitted level. At night, this figure rose to more than 70 per cent. Over 60 per cent of Euro 5 cars emitted too much nitrogen oxides during the day. At night, 100 per cent of these cars were over-emitting.

“The results are concerning. They show that it is common to manipulate the exhaust emission control of trucks, for example by installing emulators that simulate the effect of the diesel additive Adblue. With an Adblue emulator, the truck's nitrogen oxide purification system stops working completely”, says Åke Sjödin.

In the case of light vehicles, tampering with the exhaust system does not appear to be widespread. However, the tests show that emissions of both nitrogen oxides and particulate matter can be too high even for relatively new vehicles with advanced emission control equipment.

“This reinforces the need for improved environmental checks on vehicles in traffic in the EU. Vehicles that have been tampered with or do not function properly account for a large proportion of emissions and have a major negative impact on the air quality in cities. And the fact that cheating is so widespread shows how important it is that we continue to work with checks – and that there are measures such as fines”, says Åke Sjödin.

For more information see CARES website. External link, opens in new window. All reports from the project will be posted there during the summer.

In case of questions, please contact:
Åke Sjödin, ake.sjodin@ivl.se, tel. +46 (0)10-788 67 98

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