Particulate matter analysis at elementary schools in Curitiba, Brazil

Abstract

The particulate matter indoors and outdoors of the classrooms at two schools in Curitiba, Brazil, was characterised in order to assess the indoor air quality. Information concerning the bulk composition was provided by energy-dispersive x-ray fluorescence (EDXRF). From the calculated indoor/outdoor ratios and the enrichment factors it was observed that S-, Cl- and Zn-rich particles are of concern in the indoor environment. In the present research, the chemical compositions of individual particles were quantitatively elucidated, including low-Z components like C, N and O, as well as higher-Z elements, using automated electron probe microanalysis low Z EPMA. Samples were further analysed for chemical and morphological aspects, determining the particle size distribution and classifying them according to elemental composition associations. Five classes were identified based on major elemental concentrations: aluminosilicate, soot, organic, calcium carbonate and iron-rich particles. The majority of the respirable particulate matter found inside of the classroom was composed of soot, biogenic and aluminosilicate particles. In view of the chemical composition and size distribution of the aerosol particles, local deposition efficiencies in the human respiratory system were calculated revealing the deposition of soot at alveolar level. The results showed that on average 42% of coarse particles are deposited at the extrathoracic level, whereas 24% are deposited at the pulmonary region. The fine fraction showed a deposition rate of approximately 18% for both deposition levels.

Characterization, Fate, and Re-Suspension of Aerosol Particles (0.3-10 µm): The Effects of Occupancy and Carpet Use

“…The close match between the experimental curves of λ + λ d and the calculated gravitational settling rate (λ d = V g /H) with the offset values indicates that our assumptions for the particle density (ρ p ~1.7 g cm -3 ) and shape factor (χ ~1.57) of the dust particles are acceptable. It is important to note that indoor dust include crustal material and soil brought from the outdoor air, biological material, and skin scales (Davies and Noble, 1962;Clark, 1974;Janssen et al, 1999;Avigo Jr et al, 2008;Fromme et al, 2008;Parker et al, 2008;Stranger et al, 2008) which is similar to the particle composition of our assumptions in this study. Salma et al (2013) investigated the settling time of two types of dust particles: general indoor dust and chalk dust.…”

Indoor air quality of a museum in a subtropical climate: The Oscar Niemeyer museum in Curitiba, Brazil

“…In the present research, an electron probe microanalysis method, called low-Z EPMA, is applied to characterize quantitatively the composition of individual particles, including low-Z components like C, N and O, as well as higher-Z elements using a common EPMA unit (Godoi et al, 2004(Godoi et al, , 2006aAvigo et al, 2008). For EPMA, aerosol particles were sampled on Ag foil using two stages of a May cascade impactor, with aerodynamic diameters ranging from 0.5 to 2.0 μm and from 2.0 to 8.0 μm for stages 6-4 and 4-2, respectively, at a 20 L/min sampling flow to separate primarily the size fractions of interest.…”

“…The accuracy of the applied EDXRF method and of the obtained calibration curves can be found elsewhere (Avigo et al, 2008).…”

Indoor Air Quality Assessment of Elementary Schools in Curitiba, Brazil

“…The promotion of good indoor air quality in schools has been of particular public concern since school-age children spend at least 30% of their time inside classrooms (Avigo Jr et al 2008) and are more exposed to pollution because they breathe higher volumes of air (relative to their body weights), and their tissues and organs are actively growing (Mendell and Heath 2004).…”