Air pollution has long-term effects on mortality that persist decades after exposure, a large national study finds.

The study published in Thorax investigated air pollution exposures in 370 000 individuals in a national census-based cohort followed for 38 years.

The research team led by Dr Anna Hansell from the School of Public Health, Imperial College London, found that historic exposures to black smoke (BS) and SO2 were associated with increased risks of all cause, CV and respiratory mortality in England and Wales over 30 years later.

Mortality risks associated with a given exposure generally decreased over time, however subgroup analyses showed highest risks for COPD and lung cancer mortality.

Adjusting for past BS or SO2 exposures resulted in slightly lower observed mortality associations with recent PM10 exposure (suggestive of confounding), but there was no clear evidence that higher air pollution exposures in earlier life resulted in greater or lesser susceptibility to PM10, the research team said.

“Air pollution exposure may have persistent long-lasting impacts on mortality risk but that more recent air pollution exposures is associated with higher relative risks than past exposures,” they concluded.