Why are ultra-fine particles so health hazardous?
This question is still the subject of ongoing scientific research. Some possible explanations have been suggested. One is that ultra-fine particles penetrate and deposit deeper in the lungs than coarser particles. About 50% of the particles around 20 nm deposits deep in the lungs. Another explanation is that the concentration of ultra-fine particles is generally much higher than the concentration of coarser particles. The lungs cannot deal with the high amounts of particles that deposit in the lung sacs, which leads to inflammation. A third possible explanation is that the size of the particles is such that they can enter the cells in the human body and can end up in the blood stream causing heart and brain diseases.
