According to the UK's Society of Motor Manufacturers and Traders (SMMT), consumers are confused when it comes to diesel fuel's green credentials and so, with the support of a host of major car makers it is attempting to redress the balance and correct many misconceptions.
They might be more expensive to buy but new-generation diesel engine cars are cheaper to run, offer better fuel efficiency than petrol or even many hybrids and, thanks to a number of technological upgrades have also become less sluggish, quieter and kinder to the environment. However it would appear that despite ongoing popularity in the region -- 55% of new cars sold in Europe are diesels -- they're still perceived by many motorists as adding to rather than reducing pollution.
So much so that the SMMT has this week launched a UK-wide campaign, backed by Ford, BMW, Jaguar and Volkswagen to help dispel misconceptions and underline the role that cleaner diesel engines have in helping to hit stringent future cleaner air targets.
"Diesel cars produce, on average, 20% less CO2 than equivalent petrol cars and so have a vital role to play in helping to arrest climate change," said Graeme Grieve, CEO BMW Group UK. "Great strides have been taken to transform diesel engine emissions technology and continued, major investment from the industry is making them even cleaner."
From September, all new cars on sale in the EU, regardless of their engine type will have to comply with the Euro-6 emission standards, meaning that they will be the leanest from an environmental standpoint in automotive history.
However, the SMMT is concerned that in the UK, this is being ignored by policymakers who are basing fines, rewards and penalties solely on a car's engine type. For example, in some areas of London it costs more to park your car outside your home if it has a diesel engine, regardless of its emissions or fuel economy rating.
The UK is not alone in targeting diesels as a means of cleaning up its environmental act. In France, over 70% of cars on the roads are diesel and to encourage motorists to consider fuel efficient gas engines, hybrids or full electric vehicles instead, the government has increased the price of diesel fuel. Moreover it is contemplating banning cars from city centers once they've passed a certain age and launching a scheme to help drivers trade in a diesel for a gas, electric or hybrid model.
There is no debating that a well-maintained and serviced diesel engine burns less fuel than a gas engine with the same displacement. But there is also no debating that diesel engines release more potentially harmful nitrogen oxides (NOx). To counteract this, the latest diesel cars have special particulate filters but they take time -- usually 5km of travel -- to really start working at an optimum level. This issue could have been one of the contributing factors to the record pollution levels seen in Paris in March 2014 which saw the city introduce a driving ban and make public transport free in order to bring pollution levels down to below 180 micrograms of PM10 particulates per cubic meter.
"Today's diesel engines are the cleanest ever, and the culmination of billions of pounds of investment by manufacturers to improve air quality. Bans and parking taxes on diesel vehicles therefore make no sense from an environmental point of view. We need to avoid penalising one vehicle technology over another and instead encourage the uptake of the latest low emission vehicles by consumers," said Mike Hawes, SMMT Chief Executive.