number of activities can gen-erate particulates in indoor environment ranging from cooking, pets,walking across the carpet, household products generating liquid aero-sols (e.g., aerosol cans), and office equipment (e.g., printers and photo-copiers); the source processes of PM can even be associated with suchfactors as house design (e.g., construction materials of the house, thesize and arrangement of rooms, and the number of windows for venti-lation)