Quantification and characterisation of suspended particulate matter in indoor air.

Quantification and characterisation of suspended particulate matter (SPM) from homes in the city of Oslo was carried out. In 29 households the dust concentrations were found to vary between 9 and 56 mug/m(3) (median value 26 mug/m (3)). In 12 of the 29 households, a thorough analysis was carried out to determine the size and element distribution of the particles using transmission electron microscopy (TEM) and X-ray microanalysis (XRMA). The vast majority of the collected particles were less than 2.5 mum in diameter, i.e. they belonged to the fine fraction. In this fraction a considerable amount of soot and sulphur particles were found, usually less than 1 mum in diameter. The coarse fraction (particles > 2.5 mum in diameter) was found to consist mainly of organic material, silicates and larger soot aggregates. Both a thorough analysis of individual particles and a "bulk analysis" (i.e. recording XRMA spectra from whole grid masks) were performed, and the two methods were found to show good agreement.