Table 3. Summary of instruments and techniques for monitoring nanoparticle emissions in nanomanufacturing workplaces
| Metric | Instrument | Remarks |
|---|---|---|
| Aerosol concentration | CPC | Real-time measurement.
Typical concentration range of up to 400,000 particles/cm3 for stand-alone models with coincidence correction; 100,000 particles/cm3 for hand-held models. |
| DMPS | SMPS often uses a radioactive source.
FMPS uses electrometer-based sensors. Concentration range from 100−107 particles/cm3 at 5.6 nm and 1−105 particles/cm3 at 560 nm. | |
| Surface area | Diffusion charger | Need appropriate inlet pre-separator for nanoparticle measurement. Total active surface area concentration up to 1,000 µm2/cm3. |
| ELPI |
Real-time size-selective detection of active surface area concentration. 2×104–6.9×107 particles/cm3 depending on size range/stage. | |
| Mass | Size selective static sampler | Low pressure cascade impactors.
Micro-orifice impactors. |
| TEOM | EPA standard reference equivalent method. | |
| Aerosol concentration by calculation | ELPI | |
| Surface area by calculation | DMPS | |
| DMPS and ELPI used in parallel | Surface area is estimated by difference in measured aerodynamic and mobility diameters. | |
| Mass by calculation | ELPI | Calculated by assumed or known particle charge and density. |
| DMPS | Calculated by assumed or known particle charge and density. |
Abbreviations: CPC=condensation particle counter; DMPS=differential mobility particle sizer; SMPS=scanning mobility particle sizer; FMPS=fast mobility particle sizer; ELPI= electric low pressure impactor; TEOM=tapered element oscillating microbalance
Current Strategies for Engineering Controls in Nanomaterial Production and Downstream Handling Processes
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