Abstract
A VOC monitoring was carried out inside and outside a multi-storey car park in order to characterize the emission profile of
vehicular traffic source in an indoor environment. BTEX, and in particular toluene, were the most abundant compounds in all
monitored sites, with different compositions between indoor parking areas and outdoor sites. The motor vehicle exhaust and
gasoline vapor emission in these enclosed parking garages were characterized by diffusion or degradation phenomena different
from those that occur in urban areas as the BTEX compositions, their ratios and their reactivity with OH and with NO3 radicals
demonstrate. In detail, xylenes/BTEX and ethylbenzene/BTEX ratios in indoor environments were twice than those in outdoor
ones, while toluene/BTEX ratio resulted half than that obtained in outdoor sites. In this work, BTEX concentrations depend both
on number of vehicles, on vehicular characteristics (age, emission control technology, fuel quality etc.) and on factors related to
the characteristics of parking facilities (volume of the monitored areas, indoor or open facilities, ventilation systems, size and
maintenance). However, it was found that the external contribution (intrusion of pollutants from outdoor and from the other
floors) and the influence of mixing air (removal of pollutants by ventilation and air exchange) on BTEX concentrations were not
significant if inside the multi-storey car park there was a strong source (due to the number of vehicles) such happened in the first
and second floors and along the ramp that connected them.