Particle size is an important factor in determining aerosol deposition in the lungs and the absorption of aerosol compounds. In this study, the eDiluter™ Pro was used to generate the aerosol from e-vapour products. Real-time particle size distribution was measured using the Dekati ELPI+™ (Electrical Low Pressure Impactor) spectrometer. With the two-stage dilution system, the secondary stage of dilution was adjusted to collect a greater number of puffs and prevent overloading of the spectrometer. In doing so, more information related to the aerosol deliveries during device usage could be determined. Aerosol was generated using the puffing regime described in ISO 20768. The charged aerosol particles were size classified by their aerodynamic diameter (14 fractions from 6m to 10µm) in the low-pressure cascade impactor sintered plate collection set. Initial studies were performed to assess potential evaporative effects of the collection system on particle size. Using a tobacco flavored ‘ciga-like’ product with different stages of secondary dilution (7 to 14), the total mass per puff was reduced from 2.51 ± 0.36 mg/puff to 1.25 ± 0.16 mg/puff respectively. When normalizing to the fraction with the largest mass (Stage 8; 0.4 to 0.51 µm), the mass fractions remained consistent regardless of the dilution factor with coefficient of variations ranging from 2.7 to 11.3% (n=5). The data suggests the Dekati eDiluter™ Pro and ELPI^®+ system can produce consistent particle size determinations. Increased dilution has minimal impact on the particle size distribution suggesting evaporative effects of e-aerosol droplets are negligible.