Table 1.
Target and achieved aerosol concentrations and particles size of Graphistrength© C100. Temperature, relative humidity and oxygen concentration measured over the 90-day exposure period
| Groups | Control | Low | Mid | High |
|---|---|---|---|---|
| Target aerosol concentrations (mg/m3 air) | 0 | 0.05 | 0.25 | 5.0 |
| Achieved aerosol concentrations (mg/m3 air) | - | 0.06 ± 0.04 | 0.28 ± 0.06 | 4.84 ± 0.41 |
| Mean mass median aerodynamic diameter (MMAD, μm) (gravimetric determination) | - | nda | 1.62 ± 0.39 | 2.30 ± 0.34 |
| (n = 5) | (n = 14) | |||
| Mean GSD (gravimetric determination) | - | nda | 4.67 ± 4.81 | 2.47 ± 0.26 |
| Mean percentage of particles < 3 μm (gravimetric determination) | - | nda | 74.10 ± 14.00 | 63.49 ± 6.23 |
| Count median aerodynamic diameter (CMAD, nm) (WPRS determination) | - | 196.2 ± 54.7 | 231,5 ± 65.1 | 208.0 ± 62.0 |
| (n = 14) | (n = 14) | (n = 14) | ||
| Mean temperature (°C) | 23.2 ± 0.9 | 23.3 ± 0.7 | 23.6 ± 0.7 | 23.8 ± 0.6 |
| Mean relative humidity (%) | 5.8 ± 1.5 | 6.1 ± 1.7 | 6.1 ± 1.7 | 6.3 ± 1.6 |
| Mean oxygen concentration (%) | 20.8 ± 0.0 | 20.8 ± 0.0 | 20.8 ± 0.0 | 20.8 ± 0.0 |
nd: not determined
a at 0.05 mg/m3 due to the very low concentration, the particle size could not be determined by gravimetry at an air flow rate of 1 L/min. The aerosol concentrations at 0.05 and 0.25 mg/m3 were achieved by serial dilution with compressed, filtered, dry air of the 0.25 and 5.0 mg/m3 concentrations, respectively. Therefore, the MMAD and GSD at 0.05 mg/m3 are expected to be of the same order as at 0.25 mg/m3. This is also confirmed by particle size data from the 5-day study with sampling at an air flow rate of 9 L/min (see Additional file 1: Table S4 for details)