The experimental results need to be analyzed in light of our understanding of aerosol formation processes. While the EC generator operated in the batch mode has a low production rate, it offers the possibility of limiting contamination, since chemical reactions are usually excluded or limited. Particle size is determined by the rates of particle collision and subsequent coalescence. Stable nuclei collide and, initially, coalesce to form larger particles. The particles may be liquid or solid during the coalescence period.
Coalescence ceases or slows significantly, leading to the formation of agglomerate structures.
Coalescence and neck formation may continue for particles within the agglomerate structures. These processes may go on simultaneously. For example, chemical or physical processes may continue to generate condensable monomer molecules throughout the process of particle formation. In this case, after an initial surge of particle formation, further releases of monomer molecules will deposit on existing particles without generating new particles. At high temperatures and for very small particles, the individual particles grow because particle coalescence occurs almost on contact, resulting in agglomerates of large individual particles, hence small specific surface area.