Indoor/outdoor ratios
Collected outdoor PM10 concentrations allowed obtaining an
average daily profile of PM10, represented in Fig. 8. Itwas possible to
observe an increase throughout the morning, a decrease in the
early afternoon (12 he14 h), and an increase throughout the rest of
afternoon and evening, decreasing along the dawn. According to
the obtained results, PM10 concentration profiles were found
similar on weekdays and weekends.
Indoor measured concentrations were compared with outdoors
using the indoor/outdoor ratio (I/O ratio). Mean I/O ratios were
obtained for each studied room in the three nurseries (Table 5).
Generically, I/O mean ratios were always higher than 1. On a closer
look, in N_URB1, the highest I/O mean ratiowas found in LR and the
lowestwas found in classroom A, both for weekdays and weekends.
Unfortunately, there was not enough outdoor data available to
determine I/O ratio for classroom C (considering the period of
measurement in this classroom). In N_URB2, it was possible to find
the highest I/O ratio of all the studied nurseries on weekdays (in
classroom C). It is also important to point out the high I/O ratio
observed in classroom A. In N_URB3, the worst scenario was found
in LR. On weekends, I/O mean ratios were never higher than 2.65
(N_URB3, classroom A).