where Cj is the concentration of pollutant (mgm3), IR is the reason
for contact (m3 h1) and T is the exposure time (h day1). Due to the
difficulty of accurately measuring the correct rate of inhalation for
each individual, the PDwas estimated for an exposure period of 8 h,
and an IR of 1.02 m3 h1 (average inhalation) was used, as suggested
by the Exposure handbook factors [24,25].