Quantification of mass concentrations aerosols PM2.5 in primary schools. Case study: Tiaret city (Algeria)

Abstract

23 primary schools have been selected in Tiaret city, and the collection of PM_2.5 was performed in the morning, afternoon and evening, in the presence and absence of the pupils. The results found have shown a gradient of concentrations of PM_2.5 by site typology. Low and average concentrations are recorded in the areas close to forests: 23.32±2.77 µg/m³ and the high concentrations are observed in the sites exposed to road traffic: 33.57±3.27 µg/m³ in winter. However, concentrations recorded in the urban sites are lower in the summer (sites exposed to road traffic: 25.33±2.85 µg/m³, sites close to the forests 23.78± 1.92µg/m³).

We also noticed that the dominance of PM_2.5 has been observed in the vicinity of the major axes of movement. The dispersion of these particles is illustrated by a detailed maps.

The maps present information obtained by hierarchical classification, they aim to answer a need for spatial knowledge of the problem of particulate pollution in urban areas in the city of Tiaret.

The hierarchical classification allowed to distinguish three groups of schools: urban, urban highly subject to dense road traffic and schools close to green spaces and forests.

The results obtained revealed a high contamination of the atmospheric environment of the city of Tiaret by PM_2.5 aerosols, taking into account the results recorded in primary schools. Mass concentration of PM_2.5 in the 1st period (autumn and winter) is higher than that of the 2nd period (spring and summer). Indeed, the highest concentrations are recorded in the presence of pupils in winter.