Indoor Particulate Matter in Houses of Elderly in the Metropolitan Area of Sao Paulo, Brazil

Abstract:

Environmental Company of the State of Sao Paulo (CETESB), Brazil, is responsible for particulate matter measurements (PM) in the Metropolitan Area of Sao Paulo (MASP). However, there are few works with indoor measures for MASP. Therefore, the aim of this work is to investigate the PM in households in the MASP. The chosen households were there are aged people over 60 years old. The measurements were sampled during 24 hours using a Personal Cascade Impactor (SKC Cat No. 225-370), which the following aerodynamic diameters: 10.0 - 2.5 (A); 1.0 - 2.5 (B); 0.50 - 1.0 (C); 0.25 - 0.50 (D), and < 0.25 µm (E). Together the impactor, there is a Leland Legacy pump (SKC Cat No. 100-3002) with a flow of 9L/min. It was analyzed 56 households with average values of PM₁₀ and PM_2.5 of 30.7 and 23.4 µg/m³, respectively. On average, 76% of PM₁₀ consists of PM_2.5, percentage higher than the outdoor environment (60% - CETESB), and 43% of the PM_2.5 consists of PM smaller than 0.25 µm. Among all households, there was no exceedance of thresholds national standards PM₁₀ (120 µg/m³) and PM_2.5 (60 µg/m³). However, 10.7% of residences exceeded the PM₁₀ threshold of the World Health Organization (50 µg/m³) and 39.2% for PM_2.5 (20 µg/m³). The cluster analysis grouped the measures in the houses in four profiles. In three of them were greater amount of mass in ultrafine particles (E), followed by coarse particles (A) with the minimum in C level. The maximum in E may be due to the high contribution vehicular and secondary aerosol outdoor environment. The secondary maximum in A may be due to particles ressuspension and also arising from outdoors. These three groups differ only by the amount of PM measured in the households; they represent high, medium and low PM concentrations. The fourth group has average concentrations, but it presents a different profile because its maximum is in the D rather than E. All data will be analyzed concerning the possible sources.