Abstract
The influence of drying rate on the dynamic shape factor of NaCl particles was investigated. The drying rate at the efflorescence relative humidity (ERH) of 45% was controlled in a laminar flow tube and varied from 5.5 0.9 to 101 3 RH s-1 at ERH, where RH represents one percent unit of relative humidity. Dry particles having mobility diameters of 23-84 nm were studied, corresponding to aqueous particles of 37-129 nm at the RH (57%) prior to drying. At each mobility diameter and drying rate, the critical supersaturation of cloud-condensation activation was also measured. The mobility diameter and the critical supersaturation were combined in an analysis to determine the value of . The measured values varied from 1.02 to 1.26. For fixed particle diameter the value decreased with increasing drying rate. For fixed drying rate, a maximum occurred in between 35- and 40-nm dry mobility diameter, with a lower for both smaller and larger particles. The results of this study, in conjunction with the introduced apparatus for obtaining quantified drying rates, can allow the continued development of a more detailed understanding of the morphology of submicron salt particles, with the potential for the follow-on development of quantitative modeling of evaporation and crystal growth at these dimensions.
Original language | English (US) |
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Pages (from-to) | 939-953 |
Number of pages | 15 |
Journal | Aerosol Science and Technology |
Volume | 44 |
Issue number | 11 |
DOIs | |
State | Published - Nov 2010 |
ASJC Scopus subject areas
- Environmental Chemistry
- General Materials Science
- Pollution