One of the ways to improve the combustion of fuels, to make them cleaner-burning, is to put oxygen at the heart of the engine – in the molecules of the fuels. Oxygenates, principally alcohols, are either already being used, or are proposed for wider fuel inclusion.
None of this is particularly novel, as for example, ethyl alcohol (commonly known as ethanol), has been in use as a fuel or fuel additive since the first cars were built. Methanol has been in common use for competition vehicles, and BP has investigated butanol in a product known as Butamax.
Although simplest is often the best, in this case, other kinds of molecules might be better as substitution for petrol-gasoline and diesel : synthesised ethers and esters are being researched widely.
Coming at air pollution from another angle is the development of biodiesel – made from the long chain hydrocarbons in plant biomass. Again, not a new class of fuels, as plant oils were in at the start of the development of diesel engines, for example.
The most important thing about replacement fuels is that they need to perform well under a range of conditions, and research needs to include the trade-offs between different kinds of pollutants.