Diesel: Software updates are not enough

Study confirms nitrogen oxide reduction of city air by a maximum of seven percent

A study confirms that a software update on these cars will only reduce city air pollution by a maximum of seven percent. © olando o / thinkstock
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Now it is official: The software summit decided at the diesel summit is not enough. A study by the Federal Environmental Agency shows that the burden of nitrogen dioxide, even in the most favorable case, will only fall by around seven percent. For at least 70 cities in Germany, this means that the burden will remain above the limit of 40 micrograms NO2 per cubic meter of air.

At the diesel summit on August 2 between German automakers and politicians, it was about finding solutions for the high air pollution caused by car exhaust emissions in German cities. The main culprits in most metropolitan areas are diesel cars. Too small tanks for the exhaust gas cleaning, automatic shutdown in the cold and cheats in the software, the diesel cars emit significantly more nitrogen oxides than they are likely.

As a solution, politics and car manufacturers agreed at the diesel summit on an update of the control software for about five million diesel cars in Germany. Even then, however, environmental organizations and even the ADAC predicted that this would not be enough to reduce nitrogen oxide emissions enough.

Test in two scenarios

Now this has been confirmed by a study by the Federal Environmental Agency. The researchers had investigated two scenarios for this: an optimal one, which assumes an update at 3.5 million Euro-5 and 1.5 million Euro-6 diesel cars and a NO2 reduction of 25 percent on the vehicle. The second scenario was based on an update for a total of just 3.5 million diesel cars and a NO2 reduction of 15 percent.

How much this has an effect on the air pollution in the city, the researchers examined in a simulation using the example of two measuring points: One is located in the previously highly loaded Landshuter Allee in Munich, the second in Mainz Parcusstraße heavily loaded with nitrogen oxides. display

Even in the best case, only seven percent

The result: even in the most favorable scenario, the software update brings only a reduction in nitrogen oxide exposure of a maximum of seven percent, as the study showed. "However, the effect is significantly reduced if car owners refuse to update or if the updates bring only 15 percent reduction, as would be the case in Scenario 2, " the researchers said. Then the nitrogen oxide pollution of city air would only be reduced by three percent.

The reason: "That the air in the cities despite software update barely noticeably better, is simply due to the much too poor starting level of the vehicles, " says UBA President Maria Krautzberger. "Euro 5 diesels without an update today emit an average of 906 milligrams of nitrogen oxides per kilometer. That's five times more than the limit of 180 milligrams. Also current Euro 6 diesel without RDE push six times more nitrogen oxides out of the exhaust than permissible. "

Air measurement station in Hamburg Morgenstund / CC-by-sa 4.0

Continue thick air in 70 cities

But this means: "The measures are unlikely to be sufficient for almost 70 German cities to reduce the respiratory air below the limit of a maximum of 40 micrograms of nitrogen dioxide a year, " says Krautzberger. "Only in about 20 cities, which are currently just above the limit, the decisions of the diesel summit will lead to finally comply with the EU limit values ​​in force since 2010."

As the study showed, the update at heavily polluted sites such as the Landshuter Allee in Munich brings a reduction in nitrogen oxide pollution by a maximum of five micrograms per cubic meter of air. At less polluted sites, the load is only reduced by two micrograms. "That would not be a major step towards meeting the limit, " the researchers say. For in more than 25 cities, the burden is more than ten micrograms above the limit, in Stuttgart and Munich it is even twice as high.

Exchange prompts bring only a little

The exchange premiums, which the car manufacturers offer the owners of older diesel cars when buying a diesel according to the new Euro 6 standard, change little, as the study showed. Even if unrealistic 75 percent of the old diesel cars were dipped into new models, this would only bring about a three percent reduction.

"Switching from more realistic 25 percent of old diesel cars to emissions reductions of less than one percent of traffic emissions, " the researchers said. One of the reasons for this is that even the latest Euro 6 diesel engines clearly exceed the exhaust emission limits in road tests. It would bring more, if the diesel would be exchanged for a hybrid or electric vehicle or a particularly low-emission small car.

Demand for hardware retrofit is getting louder

Thus it is clear that the software updates alone and also in combination with the exchange prizes are not sufficient to solve the exhaust problem. Therefore, environmental associations and also parts of politics are calling for upgrades in the hardware of diesel vehicles. "The Diesel summit was a first step, which urgently needs to follow further and larger steps, " said Federal Environment Minister Barbara Hendricks. "The refusal of the auto industry to deal with technical upgrades is not acceptable to me."

Preparations for a second diesel summit this autumn are already underway. The aim is to avoid diesel driving bans in the cities. "I can only advise carmakers to quickly develop solutions here, " says Hendricks. "One thing must be clear: As with the software updates, the manufacturers are also responsible for the hardware retrofits. And of course, the costs of this must also be borne entirely by the vehicle manufacturers. "

The study for download (PDF)

(Federal Environment Agency / Federal Environment Ministry, 24.08.2017 - NPO)