Half of inhaled diesel soot gets stuck in the lungs: study

June 27, 2012

The exhaust from diesel-fuelled vehicles, wood fires and coal-driven power stations contains small particles of soot that flow out into the atmosphere. The soot is a scourge for the climate but also for human health. Now for the first time, researchers have studied in detail how diesel soot gets stuck in the lungs. The results show that more than half of all inhaled soot particles remain in the body.

The figure is higher than for most other types of . For example "only" 20 per cent of another type of particle from and other biomass combustion gets stuck in the lungs. 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 made on diesel particles (which mainly consist of soot) and was recently published in the Journal of Aerosol Science. Ten healthy people volunteered for the the study.

"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", says Jenny Rissler, researcher in aerosol technology at Lund University's Faculty of Engineering and responsible for publishing the study.

In population studies, other researchers have been able to observe that people who live in areas with high concentrations of are more affected by both respiratory and cardiovascular diseases. But since there is no conclusive evidence that it is precisely the soot that is to blame, the authorities have so far not taken any decisions on guidelines.

"Currently there is no specific limit for soot particles in the air, despite the fact that soot in the air is linked to both and other diseases", says Jenny Rissler.

But Jenny Rissler thinks that in the future, limits on soot levels will also be set, with reference to the WHO's recent reclassification of diesel exhaust from "probably carcinogenic" to "carcinogenic".

Soot particles are not only connected to effects on health but may also contribute to a warmer climate. Paradoxically, other types of aerosol particles can partly be desirable, insofar as they have a cooling effect on the climate and thereby mitigate the warming effect of carbon dioxide.

" are black and absorbs light, thus producing a warming effect. So it could be a double advantage to reduce it", she observes.

Jenny Rissler will next be studying individual variations in lung deposition and exposing cells to soot. She is also in the process of further developing methods to measure the surface area of the particles, as this has shown to be an important indicator of their harmfulness.

Background: Every time we breathe, we inhale tiny airborne particles, so-called aerosol particles. Some occur naturally, while others are the result of human activity. Soot mainly belongs in the latter category, as a by-product of combustion from power stations to small-scale wood fires and decorative candles. Another common source of is the exhaust from diesel engines, even though modern diesel cars have considerably reduced emissions thanks to efficient filters. The EU will be tightening rules on emissions for heavy duty diesel vehicles in 2014.

Related Stories

Recommended for you

Gene therapy improves immunity in babies with 'bubble boy' disease

December 9, 2017
Early evidence suggests that gene therapy developed at St. Jude Children's Research Hospital will lead to broad protection for infants with the devastating immune disorder X-linked severe combined immunodeficiency disorder. ...

In lab research, scientists slow progression of a fatal form of muscular dystrophy

December 8, 2017
In a paper published in the Nature journal Scientific Reports, Saint Louis University (SLU) researchers report that a new drug reduces fibrosis (scarring) and prevents loss of muscle function in an animal model of Duchenne ...

Double-blind study shows HIV vaccine not effective in viral suppression

December 7, 2017
(Medical Xpress)—A large team of researchers from the U.S. and Canada has conducted a randomized double-blind study of the effectiveness of an HIV vaccine and has found it to be ineffective in suppressing the virus. In ...

Time matters: Does our biological clock keep cancer at bay?

December 7, 2017
Our body has an internal biological or "circadian" clock, which cycles daily and is synchronized with solar time. New research done in mice suggests that it can help suppress cancer. The study, publishing 7 December in the ...

Novel harvesting method rapidly produces superior stem cells for transplantation

December 7, 2017
A new method of harvesting stem cells for bone marrow transplantation - developed by a team of investigators from the Massachusetts General Hospital (MGH) Cancer Center and the Harvard Stem Cell Institute - appears to accomplish ...

Inhibiting TOR boosts regenerative potential of adult tissues

December 7, 2017
Adult stem cells replenish dying cells and regenerate damaged tissues throughout our lifetime. We lose many of those stem cells, along with their regenerative capacity, as we age. Working in flies and mice, researchers at ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.