Inorganic fly-ash spheres as pollution tracers.

Although fly-ash particles are found in high concentrations in areas of high acid deposition little environmental work has been done on the inorganic ash sphere (IAS) component. Spatial and temporal trends of IAS in the UK show similar patterns to those of spheroidal carbonaceous particles (SCP), except that there appears to be a continuous background of IAS in the sediment record. The ratio IAS:SCP shows similar trends to both fuel-type changes as identified by SCP characterisation and historical fuel consumption records. Spatial comparisons between IAS:SCP in lake surface sediments, SCP characterisation results and known particle sources are also good. IAS concentrations in lake surface sediments and measured and modelled total, wet and dry sulphur are significantly correlated and show similar results to those of SCP studies.