Determining the count median diameter of nanoaerosols from simultaneous measurement of number and lung deposited surface area concentrations

This work focuses on the determination of airborne particle average size based on the simultaneous measurement of their number and lung-deposited surface area concentrations. In the absence of real-time size-resolved instruments, this original approach can be carried out because the ratio of these concentrations is a monotonous function of particle size. Indeed, the latter function only depends on the geometric standard deviation of airborne particle number size distribution, assumed to be lognormal.
Compared to SMPS data for polydisperse aerosols consisting in three chemical natures with count median diameters ranging from 64 to 177 nm, experimental results were found in an acceptable relative discrepancies of +/-30%. Though the method proposed is less accurate than traditional instruments like SMPS, it can be used for workplace air monitoring or as a screening tool to detect the presence of airborne nanoparticles.