Further Laboratory Experiments on Aerosol Scavenging in Mixed Clouds to Assess the Role of Phoretic Forces and Particle Solubility

Franco Prodi,Gianni Santachiara,Francesco Di Natale,Gianluca Amirante,Franco Belosi

doi:10.4236/acs.2018.82015

Abstract

Scavenging experiments have been performed in a cloud chamber inside a cold room with different aerosol particles: Paraffin particles, NaCl particles, Magnesium oxide particles, Carbon particles, Sahara dust particles. Essentially the experimental tests were carried on following the sequence of operations: the generation of the aerosol particles, their injection in the lower part of the cloud chamber, injection of water droplets in the whole chamber volume, nucleation of ice crystals, collection of ice crystals and their examination as for resulting scavenging efficiency. Evidence is given of the peculiar behaviour of soluble particles, individual and eventually inside mixed particles, leading to very much important scavenging efficiency, probably to be ascribed to aerodynamic capture. The evident peculiar behaviour of deliquescent particles can be oriented towards applications to an efficient abatement of specific effluents, on one side, and to weather modification experiments, both rain enhancement and hail prevention experiments.

Highlights

In a review on in-cloud and below cloud scavenging by ice crystals and snowflakes [1] the authors pointed out that past experimental results have been varied and difficult to interpret
Scavenging experiments have been performed in a cloud chamber inside a cold room with different aerosol particles: Paraffin particles, NaCl particles, Magnesium oxide particles, Carbon particles, Sahara dust particles
The experimental tests were carried on following the sequence of operations: the generation of the aerosol particles, their injection in the lower part of the cloud chamber, injection of water droplets in the whole chamber volume, nucleation of ice crystals, collection of ice crystals and their examination as for resulting scavenging efficiency

Summary

Introduction

In a review on in-cloud and below cloud scavenging by ice crystals and snowflakes [1] the authors pointed out that past experimental results have been varied and difficult to interpret. The reasons for that have to do with the difficulty in measuring the many parameters involved in such a three component system. Brownian diffusion and aerodynamic capture are, or might be, important in their respective domain of size, that of small particles for Brownian and of giant for aerodynamic capture. Electrostatic capture can be effective at all particle sizes and the control of charges, though not so easy, should be mandatory

Results

Discussion

Conclusion