“…Experimental studies of cloud particles (haze droplets, cloud droplets, ice crystals, etc.) may be classified in two main categories: (a) those that require large populations of particles such as cloud chambers [552,553], and methods that isolate individual particles [43,99,299,554] such as EDB [91,329], optical tweezers [67,520], acoustic levitation [89,166], etc. Single-particle studies avoid population effects, by containing the particles in a very well defined region of space under conditions of minimal perturbation [56,57,58,175,176,554].…”