OUT to facilitate a
comparison of this value with the indoor concentrations. It can be
seen that the indoor levels were higher than the outdoor ones for
each monitored site confirming the presence of indoor sources at
these workplaces. Moreover, HS6 was the most polluted as it was
characterized by a PVOC concentration equal to 3079 mg m3. On
the other hand, HS4 and HS9 were the least polluted environments