Study of the composition of PM2.5 aerosols on heavy metals in primary schools: Case of Tiaret City (Algeria)

Totally, 23 primary schools located in Tiaret city (Algeria) were chosen as sampling sites to study the aerodynamic parameters and physicochemical fine particles PM 2.5 . The collection of PM 2.5 was made in the morning, at noon, and in the afternoon, in the presence and absence of students, using a two-stage Impactor Dekati. The results found in mass concentrations (in μg/m 3 ) showed a gradient of concentrations of PM 2.5 in various study sites. Moderately low levels were recorded in areas close to forests as well as higher concentrations were observed in urban areas exposed to road traffic sites which are, respectively, 23.32 ± 2.77 pg/m 3 , 33.57 ± 3.27 pg/m 3 in winter. We observed low values as 25.33 ± 2.85 μg/m 3 in urban area exposed to road traffic and 23.78 ± 1.92 μg/m 3 in areas close to forests. The relationship between mass concentrations and meteorological factors (temperature, humidity, and wind speed) was also studied. We also note that the high concentrations of PM 2.5 were observed in the vicinities of the major traffic routes. The heavy metal content in the PM 2.5 particles was determined by ICP-MS. The maximum concentrations of Si, Pb, Zn, Cu, Al, and Ni are observed in high-traffic areas in winter in the southeast of the city, which are 21.53 ± 7.87 ng/m 3 , 63.26 ± 32.25 ng/m 3 × 10 − 4 , 54.32 ± 468 ng/m 3 × 10 − 3 , 3.61 ± 0.21 ng/m 3 × 10 − 2 , 24.87 ± 9.98 ng/m 3 , and 3.48 ± 1.11 ng/m 3 × 10 − 5 , respectively. Which are their main sources of traffic? The physical movement of students has a significant effect on the dispersion of particles in the school. This modest work intended to meet a need of spatial awareness of the problem of particulate pollution in urban areas in Tiaret city.