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Come September 2015 – that’s next month, in case you forget – RON 97 petrol fuel in Malaysia will be upgraded to a new European Fuel Directive standard, Euro 4M to replace the existing Euro 2M grade. Petronas, as we’ve been told, is already selling its Euro 4M RON 97 fuel in Peninsular Malaysia, and will officially launch it nationwide tomorrow (as revealed on its website).

So what’s this Euro 4M fuel all about – is it important?

In short, yes, it definitely is. We spoke to Petronas fuel technical expert, Chan Ming-Yau, who said that, “in essence, Euro 4M RON 97 is cleaner, adhering to a higher quality standard than before, which then leads to less vehicle emissions.” There are three major differences and improvements, concerning the fuel’s sulphur content, vapour/evaporative pressure and benzene content.

Petronas Chan Ming-yau

The most significant change is, of course, the reduction of sulphur from the current level of 500 parts per million (ppm) to just 50 ppm, as required by Euro 4M specifications. That’s a 90% decrease!

Sulphur is a naturally-occurring element present in crude oil, and has to be removed through a series of complex and costly processes. The source and/or mix of the crude oil used and the extent to which the sulphur is removed during the refining process will have to be altered to achieve the required content levels.

What’s so bad about sulphur, anyway? Well, after the combustion process within the engine, the remaining sulphur will be converted to sulphur dioxide and released into the environment. This can lead to the occurrence of acid rain, if left unchecked.

sulphur level
Fuel sulphur levels in Asia-Pacific (as of April 2014), by the United Nations Environment Programme

Moreover, for more modern vehicles with advanced emission control technologies (exhaust aftertreatment systems), high sulphur content in the fuel may “poison” the catalysts within the system. Thus, the catalytic convertors will be less effective at converting toxic pollutants in the exhaust gas to less toxic pollutants.

The use of Euro 4M fuel will help “protect” these precious metal catalysts. Also, the advent of a higher quality fuel with less than 50 ppm of sulphur allows the use of more advanced/effective three-way catalysts, which ultimately leads to better air quality for all.

Newer gasoline direct injection engines, especially – with its more diesel-like properties, more prone to emit exhaust soot (you can see the black soot build-up in the exhaust outlet of a Peugeot 208 GTi below) – will produce less sulphates/particulate matter with Euro 4M fuel.


Another change with Euro 4M standard is a lower, better vapour pressure for the fuel. With the tighter specifications of Euro 4M, the fuel’s “volatility” is reduced, with its evaporative pressure now decreased from 70 kPA (Euro 2M) to 65 kPA.

With this change in properties in place, the fuel will be less prone to evaporate, be it in the fuel tank or during the refueling process. When fuel evaporates into the air, not only is it a waste, it’s also harmful to the environment. Euro 4M fuel ensures that less of the volatile organic compounds present in fuel such as C4, C5 and C6 hydrocarbons, are released into the environment.

The third change concerning Euro 4M fuel is no less vital – the reduction of benzene content from five percent (Euro 2M) to 3.5%. Benzene is a highly volatile compound that is a known carcinogen. Human exposure to benzene has been associated with a range of acute and long-term adverse health effects and diseases, including cancer and aplastic anaemia.

This is pretty self-explanatory. The lower, the better, obviously.

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So that’s about it from a content perspective. Of course, there are other benefits to using the new higher quality RON 97 fuel. Petronas, for instance, claims that its new Primax 97 Euro 4M fuel is geared towards offering superior acceleration, on top of all the environmental benefits detailed above.

We’ll know more about Petronas’ new Euro 4M RON 97 blend when it’s officially launched tomorrow. Stay tuned.