Indoor/ Outdoor Particulate Matter Concentrations at Some Elementary Schools in Jeddah, Saudi Arabia

The mass concentrations of indoor and outdoor particulate matter (PM10, PM2.5 and PM1) have been determined at fifteen elementary schools in Jeddah, six schools in the north and nine in the south. The highest indoor and outdoor PM10, PM2.5 and PM1 (particulate matter) concentrations were found at the elementary schools in south Jeddah. In south Jeddah, the average indoor concentrations of PM were 65.44 μg/m^3, 35.85 μg/m^3 and 16.67 μg/m^3 for PM10, PM2.5 and PM1, respectively. In north Jeddah, these concentrations were 36.15 μg/m^3, 20.98 μg/m^3and 12.91 μg/m^3. In all schools in Jeddah, the average indoor concentrations of PM were 45.29 μg/m^3 for PM10, 25.42 μg/m^3 for PM2.5 and 13.46 μg/m^3 for PM1. The corresponding I/O (indoor/outdoor) ratios were 1.22, 1.08 and 1.19 for PM10, 1.52, 1.63 and 1.59 for PM2.5 and 1.60, 1.76 and 1.67 for PM1, respectively. PM levels inside the schools increased with the presence of pupils. The average concentration ratios of PM in the presence and absence of pupils inside the classrooms were 1.60 and 1.66 for PM10, 1.65 and 1.44 for PM2.5 and 1.67 and 1.54 for PM1 in elementary schools in south and north Jeddah, respectively. About 36.67% (all elementary schools of Jeddah) of indoor PM10 concentrations exceeded both the maximum 24-h and annual mean limits for PM10 set by WHO and EPA. With regard to PM2.5 concentrations, 46.67% (all elementary schools of Jeddah) of the indoor PM2.5 concentrations exceeded the maximum 24-h limits for PM2.5 set by WHO. Moreover, 100% of PM2.5 concentrations in indoor of all elementary schools in Jeddah exceeded the annual mean limits for PM2.5 set by WHO. The results of the present study can be useful in epidemiological studies on children’s exposure to PM and in the development and implementation of corrective actions for the protection of their health.