Quantification of mass concentrations aerosols PM2.5 in primary schools. Case study: Tiaret city (Algeria)
23 primary schools have been selected in Tiaret city, and the collection of PM2.5 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 PM2.5 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 PM2.5 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 PM2.5 aerosols, taking into account the results recorded in primary schools. Mass concentration of PM2.5 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.