A Department of Transport (DfT) study has recently revealed that ninety-seven percent of all modern diesel cars produce a great deal more air pollution in the real world when compared to the official legal limits.
Manufacturers of cars such as Ford, BMW and Vauxhall found there was a major difference in the amount of nitrogen oxide emissions measured in the pre-lab tests than under normal driving conditions. Those sold since 2009 emitted six times more nitrogen oxides (NOx), on average.
The diesel cars were tested by a team headed by Ricardo Martinez-Botas – a professor of mechanical engineering at Imperial College London.
Amid the vehicles tested, there were 19 types of cars that met the latest Euro 6 limit of 80mg/km NOx emissions in laboratory tests. (Euro 6 was introduced for all new cars sold after September last year.)
When driven in a real-world imitation of city, country and motorway travel, the average was nearer to 500mg/km, with some cars getting close to 1,100mg/km.
The transport secretary, Patrick McLoughlin, told The Guardian that car manufacturers needed to make changes. “Following the Volkswagen emissions scandal, the whole of the automotive industry must work hard to restore public trust by being transparent about the systems they employ and advancing plans for introducing cleaner engine technology.”
He added: “I’m disappointed the results are as bad as they are. We expected them to be different by a factor of maybe 0.5 or two on the road compared to the lab, but the levels are disappointingly high – industry needs to raise its game.”