Charging gives particles an electrical property that allows the differential mobility analyzer to separate them according to electrical mobility. This separation supports size-resolved measurement rather than treating the aerosol as one undifferentiated population. In biological studies, the approach helps distinguish particle-size ranges within bioaerosols, aerosolized cells, biomolecules, or materials produced during laboratory and environmental processes.
The differential mobility analyzer selects particles according to electrical mobility as the instrument scans across particle sizes. The condensation particle counter then detects and counts the classified particles. Combining classification with counting produces information about both the relative particle-size distribution and particle concentration, allowing investigators to compare distinct aerosol populations or follow how those populations change.
A changing distribution shows that the aerosol population is shifting across measured size ranges or that particle concentrations are changing over time. Such patterns can help characterize particles generated by biological or environmental processes and assess whether a process produces a stable or changing aerosol. The result is a time-resolved view of population changes rather than a single concentration value.
The measurement sequence begins by charging particles in the aerosol, followed by electrical-mobility separation in the differential mobility analyzer. The instrument scans across particle sizes, while the condensation particle counter detects and counts particles selected during the scan. The resulting measurements are used to construct particle-size distributions and concentrations for the aerosol under study.
Biologists may use this system when they need to characterize bioaerosols, aerosolized cells, or aerosolized biomolecules. It is also relevant for particles generated during laboratory or environmental processes. These measurements provide particle-size and concentration information that can support studies of airborne biological materials and environmental exposures, especially when particle populations may vary during the process.
Size-resolved concentration data can clarify which particle ranges are present in an aerosol and how those ranges change. That information supports evaluation of particle transport, identification of inhalation-relevant size ranges, and assessment of filtration performance. In biological and environmental work, comparing distributions before and after a process can reveal changes in the measured particle population.