Author(s)

JOANA V. BARBOSA, JULIANA P. SÁ, MARIA C. M. ALVIM-FERRAZ, FERNANDO G. MARTINS, SOFIA I. V. SOUSA

Abstract

School-age children spend most of the day at school. During this period, and regarding indoor activities, they are exposed to pollutants, namely particulate matter (PM), which can originate from dust resuspension, furniture, building materials, cleaning activities and be influenced by ventilation rates. Identifying the chemical composition of PM is essential to minimise its effects on human health. Thus, the main aim of this study was to chemically characterise the composition of indoor PM in a pre-school classroom in the PM₁₀ fraction. Indoor concentrations of PM₁, PM_2.5 and PM₁₀ were continuously measured in a pre-school classroom for approximately 2.5 days. Indoor hourly mean concentrations were compared with WHO guidelines. Simultaneously, particles were gravimetrically collected for approximately 7 days. FTIR was used to chemically characterise the PM functional groups. The results showed an increase in PM concentration at the beginning of morning activities, which alternates with decreases and increases, according to children’s occupation period, as expected. WHO guidelines were exceeded more than 61% of the time for PM_2.5 and 17% for PM₁₀. FTIR spectra allowed to identify the chemical composition of PM, namely the bands assigned to ammonium, aliphatic carbon, carbonyl group, nitrates, and sulfates. The presence of sulfates (probably ammonium sulfate and more acidic sulfate species) and nitrates (ammonium nitrate), which are formed in the atmosphere, suggests the influence of outdoor air.

Keywords

indoor air quality, particulate matter (PM), FTIR characterization, pre-school classroom, children