RÉSUMÉ
Objective To study the chemical composition and the sources of indoor PM10 in some residential houses in Beijing. Methods PM10 samples were collected using cascade impactors in smoker's and non-smoker's homes in winter. The mass concentrations and enrichment characteristics of nineteen elements, such as Al, Si, and S in airborne particles were analyzed by proton induced X-ray emission (PIXE) and enrichment factor. Results The concentrations of 19 elements were higher in smoker's homes than those in non-smoker's homes in winter, especially K and S concentrations were 2-4 times of those in non-smoker's homes. Al, Si, S, K, Ca and Fe made greater contribution to concentrations of elements in PM10, of which K and S accounted for 72% of total elements in smoker's homes while Al, Si and Ca amounted to 57% of total elements in non-smoker's homes. Conclusion Al, Si, Ca, Ti and Fe come from natural sources while S, Zn, Pb, Cr, Cu, As, Cl and P originated from anthropogenic sources such as smoking, coal combustion and oil combustion.