California air quality rules to tighten after cancer risk estimate triples

Bad air: The heavy smog shrouding the Los Angeles skyline has not stopped tourists from taking a

Factories and oil refineries in southern California face a new crackdown on their emissions of air toxins, after experts in the state reported that breathing in pollution carries almost three times the risk of causing cancer than was previously thought, especially for children and babies.

Air quality regulators covering almost 28,500sq km that are inhabited by almost 17 million people, including residents of Los Angeles, have approved new rules designed to help protect the public from poisons such as arsenic, benzene and heavy metals in industrial emissions.