STUDY OF THE RESPIRABLE IMMISSION LEVELS FOR A CYCLIST IN BRUSSELS TRAFFIC USING PIXE AS ANALYTICAL TECHNIQUE

The respirable immission levels of 11 paniculate elements (i.e. Si, S, K., Ca, Ti, Mn, Fe, Cu, Zn, Br, and Pb) for a cyclist in Brussels' traffic were assessed. To this end, a personal aerosol sampler (in which the respirable size fraction was collected on a Nuclepore filter) was carried on about 180 bicycle trips between a private home in a Brussels' suburb and an institute in the city center. All filter samples were analyzed by PIXE. The respirable immission levels of S, Pb and Zn were related to the results from stationary total aerosol collectors which are operated on a routine basis at various locations in the greater Brussels area. It was found that the cyclist's respirable immission levels can quite well be predicted from the stationary data for S, only to some extent for Pb, and not really for Zn. The 3- to 5-element data sets from the stationary samplers (with levels for S, Zn, and Pb, and occasionally also for Mn and Cu) were examined for interstation and interelement correlations. It appeared that the interelement correlations at each station were weaker than the interstation correlations for each element. The data set with concentrations of 11 elements in the bicycle trip samples was subjected to absolute principal components analysis in order to assess the dominant sources of the elements and to apportion the elemental concentrations to the sources. Four source types (components) were identified, i.e. a traffic component, a mixed road dust/soil dust/coal fly ash source, a sulfate component, and a component which was tentatively assigned to a mixture of industrial and incinerator emissions. The traffic source was responsible for most of the Pb and Br, but it was also the major source for Cu and Fe; Si, Ca and Ti originated predominantly from the mixed dust source; the sulfate component was responsible for most of the S; and the contributions from the industrial/incinerator emissions were least pronounced. © 1990.