Comparison of experimental and modeled absorption enhancement by Black Carbon (BC) cored polydisperse aerosols under hygroscopic conditions

P. M. Shamjad, S. N. Tripathi*, S. G. Aggarwal, S. K. Mishra, Manish Joshi, Arshad Khan, B. K. Sapra, Kirpa Ram

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

30 Citations (Scopus)

Abstract

The quantification of the radiative impacts of light absorbing ambient black carbon (BC) particles strongly depends on accurate measurements of BC mass concentration and absorption coefficient (βabs). In this study, an experiment has been conducted to quantify the influence of hygroscopic growth of ambient particles on light absorption. Using the hygroscopic growth factor (i.e., Zdanovskii-Stokes-Robinson (ZSR) approach), a model has been developed to predict the chemical composition of particles based on measurements, and the absorption and scattering coefficients are derived using a core-shell assumption with light extinction estimates based on Mie theory. The estimated optical properties agree within 7% for absorption coefficient and 30% for scattering coefficient with that of measured values. The enhancement of absorption is found to vary according to the thickness of the shell and BC mass, with a maximum of 2.3 for a shell thickness of 18 nm for the particles. The findings of this study underline the importance of considering aerosol-mixing states while calculating their radiative forcing.

Original languageEnglish
Pages (from-to)8082-8089
Number of pages8
JournalEnvironmental Science and Technology
Volume46
Issue number15
DOIs
Publication statusPublished - 7 Aug 2012
Externally publishedYes

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