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Table 1 Aerosol parameters determined over the entire intratracheal inhalation period of 2 h for each exposure

From: Quantitative biokinetics over a 28 day period of freshly generated, pristine, 20 nm titanium dioxide nanoparticle aerosols in healthy adult rats after a single two-hour inhalation exposure

Group of rats Instrument 1 h 4 h 24 h 7d 28d
CMD (nm), mean ± SD of 40 spectra* SMPS 23.56 ± 0.68 23.66 ± 1.01 21.61 ± 0.77 20.18 ± 1.25 23.57 ± 0.94
CMD (nm) of averaged + extrapolated spectrum& SMPS 23.00 23.00 20.00 20.00 20.00
Geom. Std. Dev. (GSD) mean ± SD of 40 spectra* SMPS 1.48 ± 0.03 1.46 ± 0.02 1.44 ± 0.03 1.45 ± 0.09 1.48 ± 0.03
GSD of averaged + extrapolated spectrum& SMPS 1.45 1.45 1.45 1.45 1.45
TiO2-NP number concen-tration (106 × #/cm3) & SMPS 2.23 ± 0.12 2.76 ± 0.18 2.23 ± 0.15 2.6 ± 2.08 2.65 ± 0.21
TiO2-NP number concen-tration (106 × #/cm3) CPC 2.47 ± 0.86 3.37 ± 0.415 2.51 ± 0.099 2.41 ± 0.168 2.89 ± 0.091
Median diameter (nm) of volume concentration SMPS 36.03 ± 2.51 34.56 ± 1.42 31.89 ± 1.33 29.73 ± 0.82 35.45 ± 0.79
TiO2-NP volume concen-tration + (10−5 cm3/m3) SMPS 2.76 ± 0.42 3.29 ± 0.34 2.1 ± 0.29 1.53 ± 0.08 3.32 ± 0.28
Specific 48V aerosol activity on filter (kBq/L)§ filter γ-spec-trometer 1.86 2.37 1.31 1.08 2.03
Mean spec. 48V act. of TiO2-NP (kBq/μg; filter Act / (Vol * dens) filter, SMPS, γ.spectrom. 12.41 18.49 14.51 15.34 15.72
Mean TiO2-NP aerosol mass conc (filter) (μg/L) # filter, SMPS, γ-spectrom. 0.15 0.13 0.09 0.07 0.13
derived porous TiO2-NP density (g/cm3) filter, SMPS, γ-spectrom. 1.83 2.73 2.14 2.27 2.32
  1. Aerosol parameters (mean ± SD; n = 4 of each group)
  2. 1 SMPS data were analyzed by AIM - Instrument Manager Software of TSI Inc. version 7.2.5.0
  3. * Mean of count median diameters (CMD) and geometric standard deviations (GSD) of all 40 SMPS spectra measured in the size range 10 nm - 420 nm
  4. & CMD and GSD of the number size spectrum averaged over all 40 SMPS spectra and mean-square fitted and extrapolated to 1-nm size; see Additional file 1
  5. + Integral particle volume concentration (PVC) of the aerosol distribution (cm3/m3) SMPS derived
  6. § Specific [48V]TiO2-NP aerosol activity determined from an aerosol filter sample continuously collected during each 2-h exposure at 0.3 L/min according to eq. 1 of Additional file 1
  7. # Derived [48V]TiO2-NP aerosol mass concentration (μg/L) dividing the specific 48V aerosol activity (filter, kBq/L) by the specific [48V]TiO2-NP activity concentration 12.4 kBq/μg