Key points from article :
Researchers say they have cracked how air pollution leads to cancer, in a discovery that completely transforms our understanding of how tumours arise.
Rather than causing damage, air pollution was waking up old damaged cells.
One of the world's leading experts, Charles Swanton, said the breakthrough marked a "new era".
The findings could explain how hundreds of cancer-causing substances act on the body.
It may now be possible to develop drugs that prevent cancer.
A series of detailed human and animal experiments were conducted.
They were able to stop cancers forming in mice exposed to air pollution by using a drug that blocks the alarm signal.
Results showed mutations alone are not always enough to cause cancer.
Doctors have trialed an interleukin-1-beta drug in cardiovascular disease.
The study took place at Francis Crick Institute in London.
