Glossary:Particulate matter - environment
Particulate matter describes tiny pieces of solid or liquid matter in the atmosphere. The main sources in urban areas are diesel-engined road vehicles, industrial, public, commercial and residential combustion. Fine particulate matter (PM10) — less than 10 micrometers in diameter— can be carried deep into the lungs where it can cause inflammation and a worsening of the condition of people with heart and lung diseases.