SHELL HAS INTRODUCED Ultra-Low Sulphur Diesel at fuel stations across the island, as part of an initiative to improve air quality in Singapore.

The fuel’s sulphur content is below 50 parts per million, making it 10 times cleaner than diesel from rival petrol companies, and about 100 times cleaner than diesel from Malaysia.

Using the new fuel in an existing diesel car could cut emissions of noxious gases like nitrous oxides and carbon monoxide by over 70 percent, and reduce particulate matter (PM) emissions by as much as 80 percent.

PM2.5, or particulates smaller than 2.5 microns, are a problem in Singapore, says National Environment Agency chairman Simon Tay. Our air doesn’t meet international guidelines for healthy levels of PM2.5, which is linked to illnesses like bronchitis and asthma. “We’re failing,” says Professor Tay candidly, adding that diesel vehicles are responsible for half the amount
of PM2.5 in the air.

Shell’s move should bring us closer to passing. Sulphur molecules are large and tend to agglomerate, adding to PM emissions, Shell’s Eric Holthusen told CarBuyer. This means ULS diesel is cleaner in itself.

Its introduction also paves the way for Euro4-compliant diesel engines to be used here. These have fine soot filters which would become clogged if used with regular diesel. Currently, the only such cars here are Mercedes-Benz E 220 CD and Skoda Superb 2.5 TDI taxis. Singapore is the first country in the region to have both the cars and fuel necessary for Euro4 compliance.

At $1.098 per litre, Shell’s ULS diesel costs nothing extra over rival fuels, despite the fact that it costs more to produce. Mr Holthusen says removing the sulphur is “an expensive process”, involving an extra step at the refinery. Shell’s launch comes a full year ahead of the October 2006 deadline for mandatory introduction of ULS diesel in Singapore.