Airborne concentrations of the wood smoke tracers, levoglucosan and finepotassium have been measured at urban and rural sites in the United Kingdomalongside measurements with a multi-wavelength aethalometer. The UK sites,and especially those in cities, show low ratios of levoglucosan to potassiumin comparison to the majority of published data. It is concluded that theremay be two distinct source types, one from wood stoves and fireplaces with ahigh organic carbon content, best represented by levoglucosan, the otherfrom larger, modern appliances with a very high burn-out efficiency, bestrepresented by potassium. Based upon levoglucosan concentrations and aconversion factor of 11.2 from levoglucosan to wood smoke mass, averageconcentrations of wood smoke including winter and summer sampling periodsare 0.23 μg m in Birmingham and 0.33 μg m inLondon, well below concentrations typical of other northern European urbanareas. There may be a further contribution from sources of potassium-richemissions amounting to an estimated 0.08 μg m in Birminghamand 0.30 μg m in London. Concentrations were highly correlatedbetween two London sites separated by 4 km suggesting that a regional sourceis responsible. Data from the aethalometer are either supportive of theseconclusions or suggest higher concentrations, depending upon the way inwhich the data are analysed.
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