There has been controversy for quite some time now about the levels of nitrogen oxide (NOx) in the air as a result of vehicles on our roads. Specific to this controversy is a comparison between large vehicles, such as buses and trucks, on the one hand and modern diesel cars on the other.
This controversy has been fuelled, so to speak, by the fact that heavy-duty diesel vehicles are subject to more stringent testing than is the case for cars. In 2015 it was estimated that cars were responsible for more than four times toxic pollution than buses and trucks. More recent findings show that figure to be much higher, as high as ten times, and according to data collected in Norway, even eleven times in cold weather. Many owners of older diesel vehicles have been tempted to sell their vehicles as a result (often to companies which buy any car).
Cars Emit Higher Levels of Pollution
What gets bus and truck owners hot under the collar, is the fact that technology to reduce the levels of NOx in cars exists; however, manufacturers are not doing enough to implement this tech. In 2015 staggering statistics showed in a study in London that certain superminis emitted the same amount of NOx as a 40 tonne vehicle. Of course this has come in the wake of the VW emissions scandal, and more parties are now aware of NOx emissions, which lead to more than 20, 000 early deaths per year in the UK alone. Part of this issue is that many diesel cars produce more NOx on the road than is shown in lab tests run by the EU – even if it does not happen via illegal methods. The problem presents itself in real driving on our roads where cars emit much higher levels of pollution than buses and trucks.
A recent report by the International Council on Clean Transportation (ICCT) revealed that heavy-duty vehicles emit 210mg NOx per kilometre, whereas diesel cars emit 500mg/km, but buses and trucks have much larger engines and would therefore burn more fuel per kilometre, with the result that the much smaller car engines are responsible for ten times more NOx emitted. Managing Director of ICCT Peter Mock feels the system is to blame: Tests on cars are carried out only in laboratories, and only on prototype cars. Buses and trucks, however, can be tested in real driving conditions with mobile testing devices.
Owners of buses and trucks feel, with good reason that cars benefit from the less stringent test measures they are subjected to. New measures are being put in place and from September new testing methods by the EU should kick in. That may be a start to bring cars in line with buses and trucks as far as this issue is concerned.