1Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, MD 20742 USA
2Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742 USA
3State Key Laboratory of Organic Geochemistry, Guangdong Key Laboratory of Environmental Protection and Resources Utilization, and Guangdong-Hong Kong-Macao Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
4CAS Center for Excellence in Deep Earth Science, Guangzhou 510640, China
5University of Chinese Academy of Sciences, Beijing 100049, China
1Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, MD 20742 USA
2Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742 USA
3State Key Laboratory of Organic Geochemistry, Guangdong Key Laboratory of Environmental Protection and Resources Utilization, and Guangdong-Hong Kong-Macao Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
4CAS Center for Excellence in Deep Earth Science, Guangzhou 510640, China
5University of Chinese Academy of Sciences, Beijing 100049, China
Received: 14 May 2022 – Discussion started: 08 Jun 2022
Abstract. In this work, we studied the Cloud Condensation nuclei (CCN) activity and subsaturated droplet growth of Phthalic acid (PTA), isophthalic acid, (IPTA) and terephthalic acid (TPTA), significant benzene polycarboxylic acids and structural isomers found in the atmosphere. Köhler Theory can be effectively applied for hygroscopicity analysis of PTA due to its higher aqueous solubility compared to IPTA and TPTA. As with other hygroscopicity studies of partially water-soluble and effectively water insoluble species, the supersaturated and subsaturated hygroscopicity derived from (KT) principles do not agree. To address the disparities in the sub- and supersaturated droplet growth, we developed a new analytical framework called the Hybrid Activity Model (HAM). HAM incorporates the aqueous solubility of a solute within an adsorption-based activation framework. Frenkel-Halsey-Hill (FHH)-Adsorption Theory (FHH-AT) was combined with the aqueous solubility of the compound to develop HAM. Analysis from HAM was validated using laboratory measurements of pure PTA, IPTA, TPTA and PTA-IPTA internal mixtures. Furthermore, the results generated using HAM were tested against traditional KT and FHH-AT to compare their water uptake predictive capabilities. A single-hygroscopicity parameter was also developed based on the HAM framework. Results show that the HAM based hygroscopicity parameter based can successfully simulate the water uptake behavior of the pure and internally mixed samples. Results indicate that the HAM framework may be applied to atmospheric aerosols of varying chemical structures and aqueous solubility.
This manuscript studied the hygroscopity and CCN activity of the organic compounds with low solubility under sub-/super-saturation conditions, and the authors developed a new analytical framework, Hygrid Activity Model (HAM), to simulate the CCN activities of compounds with varying chemical structures and aqueous solubility. This article is interesting and worthy of publication.
comments
Is HAM also performance good for simulating the mixture of insoluble compounds (such as black carbon) with the low solubility compounds? give some discussion regarding that?
The SS set to 0.6-1.6% in this study, while the SS calibration with the AS only covers from 0.2-1%, what’s the uncertainty of the SS above 1%?
Humidifier should be added between 2 DMAs in Fig. 1(b). Can you also please specify the residence time of the particles inside the humidifier, and prove this time is enough for the low-solubility (low hygroscopicity) compounds to reach the equilibrium?
The Hybrid Activity Model is a promising new droplet growth model that can be potentially used for the analysis of any type of atmospheric compound. HAM may potentially improve the representation of hygroscopicity of organic aerosols in large-scale Global Climate Models (GCMs), hence reducing the uncertainties in the climate forcing due to the aerosol indirect effect.
The Hybrid Activity Model is a promising new droplet growth model that can be potentially used...
