Belgian researchers have demonstrated that small particles can enter a person's bloodstream through the lungs.

The work is significant because it may support data on indoor air quality and illnesses other than respiratory ailments.

A "breakthrough" imaging technique using a radioactive isotope traced the flow of particles the same size as found in air pollutants into the human bloodstream.

A researcher noted that it was generally believed that the lung-blood barrier was impermeable to particles, allowing only gasses or vapors to pass through.

Particulate pollution is associated with diesel engines (including school busses) woodstoves and fireplaces, smoking, mixing and application of fertilizers and pesticides, road construction, industrial processes (steel making, mining, agricultural burning, etc.

A report appeared in the January 29 issue of Circulation: Journal of the American Heart Association and was reviewed by Reuters Health.