Indoor air quality in a domestic environment. Combined contribution of indoor and outdoor PM sources

The impact of outdoor and indoor sources on the chemical composition of particulate matter (PM) collected in a domestic environment was explored. PM2.5 samples were simultaneously collected inside (living room and bedroom) and outside a detached house located in a peri-urban area. The daily concentrations of macro-components and of micro- and trace-elements (soluble and insoluble fractions) were determined over a period of eighteen days and used to obtain detailed information about the variability of PM sources in the outdoor and indoor environments. The most important outdoor contributions to PM mass concentrations were organic and secondary inorganic species, particularly during an atmospheric stability period. A nearby congested road was responsible for the resuspension of soil related species (Si, Ca, Fe). Indoors, PM mass concentration was significantly influenced by the presence of inhabitants and their routine activities. Cigarette smoking was selectively traced by the indoor concentration profile of soluble Cd. Particularly high Cu concentrations in the bedroom were associated with the use of electric appliances equipped with brush motors (vacuum cleaner, hair dryer, electric heater). Exhaust (EC) and non-exhaust (residual Sb, Cu, Mn, Mo and Sn) traffic tracers and biomass burning related species (K and soluble Rb, Cs, Tl) were able to penetrate indoors even when the ventilation of the house was poor. An accurate estimation of the health implications due to the exposure to PM2.5 in indoor, domestic environments must consider indoor and outdoor PM source contributions in detail.