Ultrafine particles form during combustion processes, for example, when wood or biomass is burned, as well as in power-generating and industrial processes. Alongside road traffic, large airports are a major source of these ultrafine particles, which are less than 100 millionths of a millimeter (100 nanometers) in size. Because they are so small, they can penetrate deep into the lower respiratory tract, overcome the air-blood barrier and, depending on their composition, cause inflammatory reactions in the tissue, for example. What’s more, ultrafine particles are suspected of being capable of triggering cardiovascular diseases.
Click here for original story, Jet engine lubrication oils are a major source of ultrafine particles: Study
Source: Phys.org