Geochemical and size variations in inhalable UK airborne particles: the limitations of mass measurements

Current European Union legislation limits acceptable levels of inhalable particulate matter >10 mum based only on measurements of mass (currently 50 mugm(3) of PM10 per day), without considering particle shape, size or chemistry. However, SEM and inductively coupled plasma mass spectrometry data on airborne particle samples from five UK sites (Port Talbot, London, Sheffield, Birmingham and the Lizard, Cornwall) show huge variations in PM2.5/PM10 ratios and particle chemistry, irrespective of mass. Local geology, as well illustrated by the abundance of silicate particles of ophiolitic derivation from the Lizard, can be an important factor in particle variation. Thus a consideration of mass alone provides inadequate information about an airborne dust sample and any potential health effects linked to that sample.