Size Dependent Charge Measurement of Atmospheric Relevant Aerosol Species and the Implication Towards Deposition Dynamics

Abstract

Measurement of charge is important for understanding the dynamics of aerosol particles during generation, evolution and deposition phase. The effect of chemical species on the charge acquired during generation from nebulization has a significance toward laboratory and atmospheric implications. This study measures and interprets the behaviour of charge acquired by different chemical species viz. NaCl, NaNO₃, Na₂CO₃, KI, KCl, KNO₃, (NH₄)₂SO₄, (NH₄)₂C₂O₄, CsI and Cs₂CO₃ during nebulization process. The measurements of size segregated net charge reveal that one group of the above chemical species has linearly increasing trend of net unipolar charge/particle with the particle diameter and other group of species have been found to acquire charges of both the polarity. As a representative test case, deposition efficiencies for the charged particles have been estimated from the measurement data. The overall behaviour of charged chemical species translated in terms of deposition efficiency showed significant difference e.g. a factor of 9.3 for (NH₄)₂C₂O₄ compared to NaCl at 0.13 μm. The study shows that charge acquired by the particle depends on chemical species and ignoring the same may result in inaccurate estimation of depositional effect.