Particulate Matter of fewer than 10 microns diameter is referred to as PM10. Typically this will include dust, dirt, smoke, soot and liquid droplets, deposited into the atmosphere by industry and transport. They can also be formed through condensation of pollutants such as nitrogen oxide.

PM10s are well known to a major danger to human health, as long-term exposure has serious effects on respiration. They cause damage to lung tissue and are thought to cause cancer. However, the reason why they do this is not fully understood. Asthmatics are the primary victims of particulate pollution, due to inflammation of the lungs.

PM10 pollution can be highly dependant on weather patterns, with high concentration occurring on warmer, less windy days. This prevents the particulate matter from being dispersed, and particulate pollution can build up near busy roads. The concentration of particulates is expected to decrease somewhat in the next ten years, as EU regulations for vehicle emissions come into force. However, the overall levels of particulate pollution are difficult to predict, as wind patterns may blow PM10 pollution from Eastern Europe into the country.

Particulate matter in the home can be generated through many types of improperly ventilated household appliances.