Indoor PM1, PM2.5, PM10 and Outdoor PM2.5 Concentrations in Primary Schools in Sari, Iran

Abstract

This study was carried out to determine the distribution of particles in classrooms in primary schools located in the centre of the city of Sari, Iran and identify the relationship between indoor classroom particle levels and outdoor PM_2.5 concentrations. Outdoor PM_2.5 and indoor PM₁, PM_2.5, and PM₁₀ were monitored using a real-time Micro Dust Pro monitor and a GRIMM monitor, respectively. Both monitors were calibrated by gravimetric method using filters. The Kolmogorov-Smirnov test showed that all indoor and outdoor data fitted normal distribution. Mean indoor PM₁,PM_2.5, PM₁₀ and outdoor PM_2.5 concentrations for all of the classrooms were 17.6 µg m^-3, 46.6 µg m^-3, 400.9 µg m^-3, and 36.9 µg m^-3, respectively. The highest levels of indoor and outdoor PM_2.5 concentrations were measured at the Shahed Boys School (69.1 µg m^-3 and 115.8 µg m^-3, respectively). The Kazemi school had the lowest levels of indoor and outdoor PM_2.5 (29.1 µg m^-3 and 15.5 µg m^-3, respectively). In schools located near both main and small roads, the association between indoor fine particle (PM_2.5 and PM₁) and outdoor PM_2.5 levels was stronger than that between indoor PM₁₀ and outdoor PM_2.5 levels. Mean indoor PM_2.5 and PM₁₀ and outdoor PM_2.5 were higher than the standards for PM_2.5 and PM₁₀, and there was a good correlation between indoor and outdoor fine particle concentrations.