Optical characterization of native aerosols from e-cigarettes in localized volumes.

Measuring the size distribution of aerosols typically requires processing a sample, specifically to adjust the particle concentration to an adequate level. Unfortunately, this manipulation can significantly alter the native composition of some aerosols, which can lead to unreliable or even unusable measurements. We demonstrate that coherence-gated dynamic light scattering is suitable to measure the size distribution of native aerosols without the need for sample processing. Another novel aspect of the present work is the first demonstration of these type of localized light-scattering-based measurements in aerial media. Measuring the size distribution reliably in optically dense aerosols is possible thanks to the interferometric amplification of single scattering in an optically isolated, picolitre-sized coherence volume. We carried out proof-of-concept experiments in aerosols from electronic cigarettes, which poses a challenge mainly due to their high concentration, volatility, and hygroscopicity. We generated aerosols using two common moisturizers, propylene glycol and glycerol, and measured their particle size distribution as a function of the burning power. The aerosols generated in the presence of glycerol are more polydisperse and have larger particles with increasing burning power. This unique characterization of native aerosols can provide valuable information for dosimetry and hosting sites in the respiratory system.