Table 3.
Effects of changing environmental and/or aerosol parameters on the relative error in measured mass loading by different OPS types.
| OPS type | |||
|---|---|---|---|
| Low-cost OPC | High-end OPC | Nephelometer | |
| RH and hygroscopicity (Fig. 2) | Very high (20 %−200 %) for hygroscopic materials when RH > ~ 75 % | ||
| Optical properties (Fig. 4)* | Very high (30 %−100 %) | Medium (20 %−60 %) | Medium (20 %−75 %) |
| Particle size distribution (Fig. 5) | Very high 60 %−90 % | Low < 20% | High 50 %−70 % |
*
Primarily a source of error when an OPS calibrated with non-absorbing particles measures absorbing particles (or vice versa).