Multi-elemental characterization of indoor aerosols in elderly care centers

In general, elders spend more than 90 % of their daily time in indoor environments, leading to long exposure periods to indoor air pollutants. Although the recognized importance of the elders' exposure to air pollution, the research studies have been paid attention essentially to other susceptible groups of people such as children. In order to fulfill this gap in the knowledge, the objective of this work was to perform a chemical characterization of air suspended particles collected in four elderly care centers (ECCs) by using k (0) instrumental neutron activation analysis (k (0)-INAA). For that, particulate matter with aerodynamic diameter lower than 10 mu m (PM10) was sampled in ECCs' bedrooms, living-rooms and, at the same time, in the respective outdoors. The collected filters were irradiated at the Portuguese Research Reactor (nominal power: 1 MW) and measured using a coaxial germanium detector for the application of the k (0)-INAA. Results showed that the PM10 indoor concentrations did not exceed the national and the international limit values and that PM10 concentration in living-rooms were significantly higher than in bedrooms. Zn and Cr presented higher concentrations in the indoor environments indicating the existence of indoor sources for these elements. The most enriched elements in relation to a reference soil were Sb, Zn, As and Cr indicating their association with anthropogenic sources. This article represents an innovation in the field of environmental chemistry since the PM chemical components have never been characterized in ECCs.