Figs. 3, 5 and 7 showed that PM concentrations in the classrooms
started to rise up at the beginning of the occupancy period
and started decreasing after the end of the occupancy period (time
variable, depending on the room). Figs. 4, 6 and 7 showed that the
concentrations during weekends and non-occupancy periods did
not seem to have high fluctuations neither peaks, thus being
considered background concentrations for each respective room.
The highest PM1 and PM2.5 concentrations were registered in
N_URB2 (classroom C), while the highest PM10 and PMTotal concentrations
were found in N_URB1 (classroom C). The minimum
concentrations of all PM fractions were observed in the LR of