Air pollution may have triggered the premature yearly deaths of at least 29,000 people in Britain alone.
But the figure could be as high as 200,000 deaths a year because of long-term exposure to an unhealthy environment.
It adds to mounting evidence of the health dangers of pollution, which is already known to play a part in asthma attacks, heart attacks and strokes the Daily Mail reports.
Microscopic particles largely generated by diesel exhausts have previously been shown to damage the lungs and cause harmful changes in blood vessels and clotting.
The latest assessment comes from the Committee on the Medical Effects of Air Pollutants, a government advisory panel of independent experts.
Professor Jon Ayres, the panel's chairman, said, "The report clearly shows that particulate air pollution continues to have a significant effect on health. Importantly, it shows reducing concentrations would lead to significant gains for public health."