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CCN closure study: Effects of aerosol chemical composition and mixing state

TLDR
In this article, the effects of chemical composition (bulk and size resolved) and mixing state (internal and external) on CCN activity of aerosols were investigated during the winter season in Kanpur.
Abstract
This study presents a detailed cloud condensation nuclei (CCN) closure study that investigates the effects of chemical composition (bulk and size resolved) and mixing state (internal and external) on CCN activity of aerosols. Measurements of the chemical composition, aerosol size distribution, total number concentration, and CCN concentration at supersaturation (SS = 0.2–1.0%) were performed during the winter season in Kanpur, India. Among the two cases considered here, better closure results are obtained for case 1 (low total aerosol loading, 49.54 ± 26.42 μg m−3, and high O:C ratio, 0.61 ± 0.07) compared to case 2 (high total aerosol loading, 101.05 ± 18.73 μg m−3, and low O:C ratio, 0.42 ± 0.06), with a maximum reduction of 3–81% in CCN overprediction for all depleted SS values (0.18–0.60%). Including the assumption that less volatile oxidized organic aerosols represent the soluble organic fraction reduced the overprediction to at most 40% and 129% in the internal and external mixing scenarios, respectively. At higher depleted SS values (0.34–0.60%), size-resolved chemical composition with an internal mixing state performed well in CCN closure among all organic solubility scenarios. However, at a lower depleted SS value (0.18%), closure is found to be more sensitive to both the chemical composition and mixing state of aerosols. At higher SS values, information on the solubility of organics and size-resolved chemical composition is required for accurate CCN predictions, whereas at lower SS values, information on the mixing state in addition to the solubility of organics and size-resolved chemical composition is required. Overall, κtotal values are observed to be independent of the O:C ratio [κtotal = (0.36 ± 0.01) × O:C − (0.03 ± 0.01)] in the range of 0.2<O:C<0.81, which indicates that the variation in the chemical composition of aerosols is not well represented by the changes in the O:C ratio alone.

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Citations
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Study on CCN activity of fission product aerosols (CsI and CsOH) and their effect on size and other properties

TL;DR: In this article, the size resolved cloud condensation nuclei (CCN) properties of two cesium bound compounds viz. CsI and CsOH are discussed in context of risk analysis and management of probable environmental releases during postulated nuclear reactor accident conditions.
Journal ArticleDOI

The impact of aerosol size-dependent hygroscopicity and mixing state on the cloud condensation nuclei potential over the north-east Atlantic

TL;DR: In this article, the authors presented an aerosol cloud condensation nuclei (CCN)closure study over the north-east Atlantic Ocean using six approximating methods, and found that a good agreement was found between estimated and measured NCCN with linear regression slopes ranging from 064 to 16 The temporal variance was captured very well, with Pearson's R value ranging between 076 to 098 depending on the method and air mass type.
Journal ArticleDOI

Influence of Common Assumptions Regarding Aerosol Composition and Mixing State on Predicted CCN Concentration

TL;DR: A 4-year record of aerosol size and hygroscopic growth factor distributions measured at the Department of Energy's Southern Great Plains (SGP) site in Oklahoma, U.S. were used to estimate supersaturation (S)-dependent cloud condensation nuclei concentrations (NCCN) as discussed by the authors.
Journal ArticleDOI

Characterization of submicron aerosols over the Yellow Sea measured onboard the Gisang 1 research vessel in the spring of 2018 and 2019.

TL;DR: The physico-chemical properties of submicron aerosols were measured in the spring of 2018 and 2019 over the Yellow Sea onboard the Gisang 1 research vessel as mentioned in this paper.
Journal ArticleDOI

How secondary inorganic aerosols from Delhi influence aerosol optical and radiative properties at a downwind sub-urban site over Indo-Gangetic Basin?

TL;DR: In this paper, the authors compare and contrast aerosol emissions, compositions and related optical and radiative properties for two different environments, and highlight that diverse near-surface emissions together with atmospheric processing leads to strong inter-seasonal spatial heterogeneity in aerosol chemical, optical properties between the adjacent distinct sites.
References
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Journal ArticleDOI

Climate Forcing by Anthropogenic Aerosols

TL;DR: The aerosol forcing has likely offset global greenhouse warming to a substantial degree, however, differences in geographical and seasonal distributions of these forcings preclude any simple compensation.
Journal ArticleDOI

Evolution of Organic Aerosols in the Atmosphere

Jose L. Jimenez, +66 more
- 11 Dec 2009 - 
TL;DR: A unifying model framework describing the atmospheric evolution of OA that is constrained by high–time-resolution measurements of its composition, volatility, and oxidation state is presented, which can serve as a basis for improving parameterizations in regional and global models.
Journal ArticleDOI

Organic aerosol and global climate modelling: a review

TL;DR: In this article, the authors reviewed existing knowledge with regard to organic aerosol (OA) of importance for global climate modelling and defined critical gaps needed to reduce the involved uncertainties, and synthesized the information to provide a continuous analysis of the flow from the emitted material to the atmosphere up to the point of the climate impact of the produced organic aerosols.
Journal ArticleDOI

A single parameter representation of hygroscopic growth and cloud condensation nucleus activity

TL;DR: In this paper, a method to describe the relationship between particle dry diameter and cloud condensation activity using a single hygroscopicity parameter is presented. But this method is limited to single and multi-component particles with varying amounts of inorganic, organic and surface active compounds.
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