United Nations Environment Programme

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Tool 9: Unleaded petrol


For petrol vehicles, unleaded petrol (gasoline) should be used. Unleaded petrol is better for the engine, eliminates emissions of lead particles, and enables the use of a catalytic converter (See Tool 12) for further emissions reductions.  

Lead has several health effects, but the most serious are its neuropsychological effects and damage caused to the central nervous system. Especially affected are children, for whom exposure to lead may lead to learning disabilities. The box below lists estimated health impacts from the use of lead in Egypt.

Photo: Fleet Forum

In Cairo, Egypt, lead from all sources* was estimated to cause every year:

6 500 to 11 200 heart attacks,
800 to 1 400 strokes,
6 300 to 11 300 premature deaths,
820 infant deaths and
An average IQ loss of 4.25 in every child.
Egypt went unleaded in 1999


*Leaded fuel contributed approximately 2/3 of ambient lead, while smelters produced about 1/3.
Source: UNEP/PCFV


Why was lead used in the first place? Lead was introduced to enhance the octane rating of petrol, which prevents engine knocking and results in smoother engine operation. Today, modern refineries do not need to add lead to petrol in order to attain desired octane ratings. Several alternative additives that can boost octane exist, such as MTBE, MMT and ethanol. In addition, refineries can be upgraded to produce petrol with the desired octane rating, without using additives. The most cost-effective way to produce unleaded petrol - either through additives or refinery upgrades - depends on the design of the refinery.


Ethanol for phasing out lead?
Ethanol is a known octane booster and can successfully be blended with petrol up to 10%. The use of ethanol prevents the need for lead, and as a renewable fuel, reduces net emissions of CO2 and dependence on oil.


All vehicles can run on unleaded petrol: the claim that some vehicles need leaded fuel is not true. Modern fuels with the right octane rating are better for engines; in addition, use of unleaded petrol results in less wear and tear on other vehicle components, such as the exhaust system. For very old cars (pre-1978), there was a legitimate concern that piston valve seats might be damaged if using unleaded petrol. However, this turned out to be much less of a problem than first anticipated. As can be seen from the map below, unleaded petrol is now the standard in virtually every country around the world.



Figure 6: World map showing the availability of unleaded versus leaded petrol. Source PCFV/UNEP



In most parts of the world, the use of leaded fuel is forbidden. However, in some developing and transitional countries, leaded fuel is still available. Reasons for still using leaded petrol vary, such as the operation of old refineries, and a lack of incentives, capital and/or awareness among fuel producers. Ironically, oil-exporting countries still offer leaded fuel. Unleaded fuel was introduced in the US and in Japan in the 1970s; in the US, leaded fuel has been banned since 1986 and since 2000 in the EU.

For more info on unleaded petrol >> www.unep.org/pcfv