(7a) Primary Ion Diffusion Charging and Particle Wall Loss in Smog Chamber Experiments

We investigate the effect of primary ion diffusion charging on particle wall loss in Teflon smog chamber experiments. Primary ion losses are balanced between wall deposition and diffusion charging to larger particles; further, the particle charge distribution evolves toward a chamber-specific charge steady state, different from the so-called “neutralizer steady state” attained inside laboratory neutralizers. This chamber charge steady state depends on the particle size distribution, and the timescale to reach it is often hours. Applying conditions typical of chamber experiments, we conclude that primary ions play an important role in particle wall loss and should be taken into consideration when interpreting experiments.