Cl − , and NO 2− , were present in PM at less than 1.0 μm(B3) and lower concentrations of nitrite, magnesium, cal-cium, sulfate, phosphate, and oxalate. In the B1 and B2,an increase can be observed in the magnesium, calcium,phosphate, and nitrite concentrations (Fig. 6a).In Fig. 6b, the highest concentration of the species inthe different filters of the isokinetic samplers was found forthe PM 2.5 (B1).