Now for the first time, Lund University researchers have shown in a detailed study how more than half of all inhaled diesel soot particles remain in the body.
The figure is higher than for most other types of particles. For example, only 20 per cent of another type of particle from wood smoke and other biomass combustion gets stuck in the lungs, the Journal of Aerosol Science reported.
One explanation is that diesel soot is made up of smaller particles and can therefore penetrate deeper into the lungs, where it is deposited. The study was based on diesel particles (mainly soot), said a university statement.
"Findings of this kind can be extremely useful both for researchers to determine what doses of soot we get into our lungs out of the amount we are exposed to, and to enable public authorities to establish well-founded limits for soot particles in outdoor air," said Jenny Rissler, aerosol technology researcher at Lund University's Faculty of Engineering, who led the study.
"Currently there is no specific limit for soot particles in the air, despite the fact that soot in the air is linked to both lung cancer and other diseases", said Rissler.
Soot particles are not affect health but may also contribute to a warmer climate. Paradoxically, other types of aerosol particles can partly be desirable, so far as they have a cooling effect on the climate and thereby mitigate the warming effect of carbon dioxide.
"Soot particles are black and absorbs light, thus producing a warming effect. So it could be a double advantage to reduce it," Rissler observed.