Breathing in particulate matter damages the body in two ways:
- Inflammation: Particulate matter is believed to be mistaken by the body for an infection, triggering an inflammatory response. This causes shortness of breath and exacerbates pre-existing respiratory symptoms, particularly asthma and COPD. That inflammation can spread to other parts of the body, risking heart attacks, stroke and cardiovascular disease. For pregnant women, this inflammation can reach the uterus (see below)
- Bloodstream: small particles can reach the bloodstream where it can enter other areas of the body and impact the health of all organs, and even get through the placenta to the baby
Particulate matter has been associated with health impacts even at very low concentrations. No threshold has been identified below which no damage to health is observed.
Gaseous pollutants like NO2 or ozone irritate the airways, exacerbating lung related diseases. SO2 has also been linked to increased hospital admissions to cardiac disease and mortality.