Since humans spend most of their time indoors (ca 90%), BaPeq
concentrations in indoor microenvironments will be the greatest
contributors to the total carcinogenic burden of inhaled air. From
Table 2 it can be estimated that indoor environments will contribute
87% of the total carcinogenic risk of the inhaled air, when subjects
spent 90% of their time indoors. Even short exposures (e.g. 1 h) of
individuals in indoor microenvironments with high PAH levels (e.g.
pubs) can make a large contribution to the total carcinogenic risk from
PAH inhalation. In this example, the pub, other indoor microenvironments
and outdoor air will make a contribution of ca. 20%, 70% and
10% respectively to the total carcinogenic risk inhaled. This result
highlights the importance of indoor air as a contributor to the total
PAH burden from inhalation.