Comparison of polychlorinated biphenyl concentrations in indoor and outdoor air and the potential significance of inhalation as a human exposure pathway

Polychlorinated biphenyl (PCB) concentrations were measured in air from a total of 14 different indoor environments in Birmingham and the West Midlands area of the United Kingdom and compared to ambient outdoor levels. In four instances, spatially and temporally consistent indoor and outdoor samples were taken for comparison. Other indoor samples were compared to 25 outdoor samples from the Birmingham area taken at regular intervals between February 1997 and February 1998. Higher levels were present in indoor air (1.1-69 ng of Sigma PCB m(-3) mean = 9.0 ng of Sigma PCB m(-3)) than in outdoor air(0.08-1.5 ng of Sigma PCB m(-3), mean = 0.31 ng of Sigma PCB m(-3)). This limited data set indicates daily mean background U.K. PCB intake via inhalation to be 110 ng of Sigma PCB person(-1) (0.7 pg of Sigma i-TE person(-1)), with a range of 23-590 ng of Sigma PCB person(-1) (0.03-2 pg of Sigma i-TE person(-1)). Inhalation may thus represent a significant exposure pathway to Sigma PCB but not Sigma i-TE for some individuals, given that 1992 daily U.K, intake of PCB via diet has been estimated elsewhere to be 340 ng of Sigma PCB person(-1) (54 pg of Sigma i-TE person(-1)).