FIG. 3.

EECR estimation for atrophy of olfactory epithelium in the olfactory region of the nose at level 2. Male rats at the end of the inhalation period of the subchronic inhalation toxicity study. Data points with error bars (mean values with SE) represent the scoring of histopathological findings for the different exposure groups. For the 1R4F cigarette the concentration response curve is plotted on a μg TPM/L basis. Arrows indicate the estimation of the concentration of 1R4F MS causing an effect comparable to the one of the EHC MS. The EECR is calculated by dividing the corresponding 1R4F concentration through the EHC concentration.