A re-evaluation on the atmospheric significance of octanal vapor uptake by acidic particles : Roles of particle acidity and gas-phase octanal concentration

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

8 Scopus Citations
View graph of relations

Author(s)

Detail(s)

Original languageEnglish
Pages (from-to)992-1000
Journal / PublicationAerosol Science and Technology
Volume42
Issue number12
Publication statusPublished - Dec 2008
Externally publishedYes

Abstract

An electrodynamic balance was used to investigate the uptake of octanal vapor by single sulfuric acid droplets levitated under various relative humidity (RH) conditions and gas-phase octanal concentrations. In the high octanal concentration experiments (200-300 ppm), we observed that the organic mass yield depended on the acidity of the sulfuric acid droplets and significant uptake of octanal only occurred when the RH was about 10% (H2SO4 wt% ∼64%). Furthermore, repartitioning of only a portion of condensed organic compounds was observed after active dilution with octanal-free compressed air, indicating that low-volatility products had formed and that repartitioning is important in affecting the organic mass fraction and chemical composition of atmospheric organic aerosols. When a relatively lower octanal concentration (700-900 ppb) was used, no significant uptake of octanal vapor by the sulfuric acid droplets was observed even at 10% RH with long exposure time (>25 h). Our findings suggest that both particle acidity and gas-phase octanal concentration are the critical factors that influence the organic mass yield of levitated acidic droplets. Because of the severe conditions of low RH and high octanal conditions required to effect the reactions, the reactive uptake of aldehydes, especially those that have chemical structures and properties very similar to octanal, into acidic particles may not be an important pathway in secondary organic aerosol formation under actual atmospheric conditions. Copyright © American Association for Aerosol Research.

Citation Format(s)

A re-evaluation on the atmospheric significance of octanal vapor uptake by acidic particles : Roles of particle acidity and gas-phase octanal concentration. / Lee, Alex K. Y.; Li, Yong Jie; Lau, Arthur P. S.; Chan, Chak K.

In: Aerosol Science and Technology, Vol. 42, No. 12, 12.2008, p. 992-1000.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review