Current 24-hour average particulate matter concentrations of less than 10 micrometres (μm) in Belgium
The smaller the particulate matter, the deeper it can get through the airways in the human body. The smallest particles can penetrate into the blood. PM10 can disrupt the mucous membrane in the airways, cause respiratory complaints and increase sensitivity to respiratory infections. Among other things, the presence of polycyclic aromatic hydrocarbons (PAHs) in some dust particles promotes the development of lung cancer. Other toxic constituents of particulate matter can spread even further in the (human) body after deposition in the lungs via the bloodstream or the lymphatic system. Exposure to high peak concentrations of particulate matter also increases the risk of having a heart attack. Ultrafine particles (UFP or PM0,1) penetrate deeper into the lungs than larger particles, have a much larger surface area per unit mass, and can get directly into the bloodstream. There are increasing indications that especially the combustion particles (mainly from the outlets in traffic) of UFP can cause health effects. It is not yet 100% clear what mechanisms lie behind these health effects.