This study investigates the measurement of plasma‐grown nanoparticles, comparing ex situ scanning electron microscopy (SEM) and an in situ light scattering method which is based on Mie theory and utilizes a neural network for evaluation. The research reveals that the particle size distribution (PSD) is normal and very narrow, supporting the common assumption of monodisperse particle clouds. Importantly, the study finds that the spread of the PSD increases proportionally with the mean size, suggesting varied growth rates based on the radius of the spherical dust grains. Both methods produce consistent results, which encourages the use of the interference‐free, real‐time, light‐based Mie method in similar studies.