Airborne particulate matter (PM (sub 10) ) in the china clay area, Cornwall, UK

Work was undertaken in 1997 as part of a UK government programme to monitor air quality in the Cornish china clay area. These studies showed that concentrations of airborne particulate matter with an aerodynamic diameter <10 mu m (PM (sub 10) ) did not exceed UK National Air Quality Strategy (NAQS, 1995) guidelines but were, however, greater than those normally associated with rural areas. Subsequently, in the summer of 2000, airborne dust sampling was conducted at three sites around the IMERYS (formerly ECCI) Kernick mica dam, a potential source of resuspended airborne particulates from china clay waste minerals. Analytical scanning electron microscopy examination of the collected material suggested that up to 61% of the airborne PM (sub 10) monitored next to the mica dam could be associated with china clay extraction compared with 46% 2 km to the south. Results showed the presence of substantial percentages of respirable kaolinite, muscovite and quartz; the major components of china clay waste. The health effects of the particular mineral dust emissions associated with china clay mining are reviewed.