SIR – There is much said regarding the detrimental effect of the motor car – the pollution, global warming and the loss of our flood plains, gobbled up with motorway construction.

But I have often wondered how much of the Earth’s atmosphere is driving around in the immeasurable millions of car tyres on our roads and what effect this is having on we humans. Also, hypothetically speaking, what would be the effect if all the world’s tyres were let down simultaneously? Just wondered.

Elaine Neale, Gordon Terrace, Idle