Performance of a slit virtual impactor operated at high particle mass loading

We report the performance of a slit virtual impactor at high particle mass concentrations . Transmission efficiency was determined on an individual particle basis by visualization of fluorescent particles embedded in a background matrix of Arizona road dust. No significant difference in transmission efficiency from dilute conditions was observed for a mass loading of . At greater mass loadings , the device clogged before a statistically significant data set could be obtained. These results suggest that the performance of a slit virtual impactor is not degraded up to roughly , and may be extended to even larger mass loadings provided that clogging of the nozzle is minimized.