Das Projekt "EXPOLIS II: Elementaranalytische Untersuchung zu personenbezogener Feinpartikelaufnahme (PM 2,5) in Innen- und Aussenraeumen das EAS-Projekt" wird vom Umweltbundesamt gefördert und von Universität Basel, Institut für Sozial- und Präventivmedizin durchgeführt. The project analyses the chemical elements on the PM2,5 particulate matters as collected on filters in the framework of the EXPOLIS study (Basel, Athens, Helsinki, Prag, Milano, Grenoble). In each city a random population sample of 50 subjects (Helsinki 250) participated in a personal exposure assessment over 48 hours. PM2,5 were collected on personal monitors, at home indoor, at home outdoor, at work indoor. The EAS study analyses the chemical elements on these filters to address specific differences of indoor and outdoor particulate matter with its respective relevance for personal exposure. Tracers of specific exposures will be used to improve the source apportionment of personal particulate exposure. Leading Questions: What is the chemical content in PM2,5 among adult urban populations in Europe? What personal and environmental key parameters affect the chemical element distribution in personal, indoor and outdoor PM2,5 filters? What is the difference in the content of source specific chemical elements in indoor and outdoor particulate matter?