Unleaded fuel

Has no lead which suppresses the harm it causes to the environment.Unleaded petrol is petrol manufactured without the addition of a substance called anti-knock, a compound containing lead that was originally put into petrol to prevent knocking in the engine and to promote smooth running. Unleaded petrol has a slightly lower octane rating than leaded petrol, but is has other compounds added so that performance is not really impaired. It has the advantage that its use does not release lead compounds into the atmosphere from exhaust fumes.

Leaded fuel

lead comes out in the combustion products in the exhaust and lead is a toxic material to humans over a long period of time when inhaled or ingested. Over time lead can also build up in the soil effecting the environment as we'll.

Leaded vs unleaded