Leaded petrol eradicated, says UNEP

Context:

The UN Environment Programme (UNEP) said that the use of leaded petrol has been eradicated from the globe.

It is a milestone that will prevent more than 1.2 million premature deaths and save world economies over $2.4 trillion annually. It has taken 100 years to stop the use of leaded fuel finally.

Relevance:

GS-III: Environment and Ecology (Environmental Pollution and Degradation, Conservation of Environment)

Dimensions of the Article:

1. Need to stop using lead
2. Engine Knocking and Leaded petrol and the need to stop its use
3. India’s tryst with leaded petrol

Engine Knocking and Leaded petrol and the need to stop its use

• An Internal combustion engine under load develops `pinging’ or `knocking’, where the fuel mixture starts exploding due to compression before the right time, causing rough running, stalling going up hills, and so on.
• Tetra Ethyl Lead (TEL) is one such component that is added to petrol to reduce its tendency to `ping’ under compression. TEL breaks down to lead at upper cylinder temperatures. Lead atoms spread around and combining with the free radicals and slowing down the reaction.
• TEL was first being mixed with petrol beginning in the 1920s as a patented octane rating booster that allowed engine compression to be raised substantially.
• This in turn caused increased vehicle performance and fuel economy.
• The practice of adding tetraethyl lead to petrol had spread widely to all countries soon after its anti-knock and octane-boosting properties were discovered.
• TEL is still used as an additive in some grades of aviation gasoline.

Need to stop using lead

• `Leaded’ petrol is a grave danger to the environment, as lead is a poison when it is absorbed into the body.
• Lead is toxic, affects multiple body systems and is particularly harmful to young children.
• It affects the brain, liver, kidneys and bones. Lead is measured in blood to understand exposure.
• Lead in bone is released into blood during pregnancy and becomes a source of exposure to the developing foetus.
• More recent research has indicated that lead can damage the infant brain even at blood levels as low as 5 microunit per decilitre (μ/dl).

The real reason

• However, the reason for going completely unleaded is different – it is to reduce other pollutants.
• To reduce unburned hydrocarbons and nitrogen oxides – catalytic exhausts have been adopted and they cannot stand even the residual lead, which will affect the platinum catalyst. (The platinum catalyst filter causes a catalytic conversion of the oxides to other products , hence, passing the exhaust gases through a filter of platinum prevents the greenhouse gasses from escaping into the atmosphere.) Lead affects the function of platinum and hence its use in fuel needs to be restricted.

India’s tryst with leaded petrol

• India was among those countries that took early action to phase out leaded petrol. The process of phase down that had started in 1994, got completed in 2000.
• Initially, low-leaded petrol was introduced in Delhi, Mumbai, Kolkata and Chennai in 1994, followed by unleaded petrol in 1995.
• The entire country got low-leaded petrol in 1997 while leaded fuel was banned in the National Capital Territory of Delhi.
• The final introduction of unleaded petrol in the entire country was mandated in April 2000.
• This decision was also catalysed by the Supreme Court order that had directed the introduction of unleaded petrol to enable the adoption of catalytic converters in petrol cars.

-Source: The Hindu