Two primary standard reference fuels, normal heptane and iso-octane arbitrarily assigned 0 and 100 octane number, respectively, are then blended to produce the same knock intensity as the test sample.

The WHO's projection for fewer deaths is based mainly on reducing PM10, caused by burning fossil and other fuels, from a reference point of 70 micrograms per cubic metre down to 20.

The paper discussed the problem of fuels separation, dynamic behaviour and environmental protection in manufacturing M15 methanol gasoline cleaning fuel additive for reference.