The countdown to cleaner cars has begun

The toughest ever standards for vehicle exhaust emissions are just 100 days away from coming into force Europe-wide.

From September 1, all new petrol and diesel-powered cars sold within the European Union will have to produce significantly less carbon dioxide, nitrogen oxide and a host of other air pollutants if they're to be deemed Euro-6 compliant.

The legislation has given carmakers a headache in that they have had to plumb the depths of their imagination and technical capabilities in order to improve their diesel engines to meet the targets.

However, their challenge is everyone else's good fortune. As the cleanest vehicles in history start rolling out onto European roads, air quality is set to improve measurably.

Data published by the EU in April shows that the pollution emitted by the average new car has fallen by almost one third since it started imposing emissions restrictions with Euro-1 in 1993, but a jump is expected with the move to Euro-6 regulations as they specifically target diesel cars and their generation of nitrogen oxide (NOx), a gas linked to health issues as well as climate change.

From September, a new car's diesel engine cannot emit more than 80 mg/km of NOx and 5mg/km of particulate matter (PM), a huge jump over the outgoing Euro-5 standard, introduced in 2011, which permitted NOx emissions from diesels of 180mg/km.

Roughly half of all new cars currently on sale in Europe already comply with Euro-6 regulations and the latest new vehicle registration data suggests that consumers are already plumping for the cleanest engine options when buying a new car. For example, in the UK, 70% of new cars sold in April were Euro-6 compliant.

"With 100 days still to go until the new Euro-6 standard becomes mandatory, new car buyers are shifting to these next-generation vehicles. This is the result of huge investment from manufacturers in clean technology -- and the quicker we get these Euro-6 cars onto the roads, the quicker we'll see improvements in air quality," said Mike Hawes, the chief executive of the Society of Motor Manufacturers and Traders.

However, the next raft of legislation, expected to become law in 2020 will raise the bar yet again, so much so that car companies will have to finally consider alternative forms of power -- be it hybrid, plug-in electric or fuel cell technology, in order to further cut CO2, NOx and particulate emissions.