Centre for Atmospheric and Oceanic Sciences, Indian Institute of Science, Bengaluru, India
Abstract. The state of mixing of aerosols significantly influence their transformation, deposition, radiative forcing and health effects. We report the realistic (as in the atmosphere) state of mixing and morphology of aerosols at two nearby but contrasting environments; the urban region Bengaluru and a remote region Challakere. Ambient aerosols are collected on filter substrates using a High-Volume Sampler and analysed using Scanning Electron Microscope (SEM) equipped with Energy Dispersive X-Ray spectroscopy (EDX). The results show that the prevailing state of mixing of aerosols is 'core-shell' with SiO2 as the core and Carbon-SiO2-others (Calcium-Magnesium-Aluminium and other dust origin elements) combinations as the shell. On an average, for Bengaluru (Challakere), 66 % (51 %) of the core surface is coated. The sample-wise mean Carbon content of the composite particles reaches as high as ~ 26 % (~ 9 %) at Bengaluru (Challakere). The ambient black carbon (BC) mass concentration and the amount of rainfall that occurs just prior to the end of sampling are found to significantly influence the Carbon content of the particles. To the best of our knowledge, this is a first-of-its kind study over Indian region, coupling realistic aerosol observations and spectroscopy along with advanced image processing techniques to investigate the state of mixing and morphology of atmospheric aerosols at single particle resolution. This knowledge regarding the real-life state of mixing of aerosols would be useful in constraining the models studying aerosol-radiation interactions.
How to cite. Hariram, C. R., Govardhan, G., Manoj, M. R., Anand, N. S., Kannan, K., Satheesh, S. K., and Moorthy, K. K.: Morphology, Chemical Composition and Mixing State of
Atmospheric Aerosols from Two Contrasting Environments in
Southern India, Atmos. Chem. Phys. Discuss. [preprint], https://doi.org/10.5194/acp-2018-745, 2018.
Received: 20 Jul 2018 – Discussion started: 20 Aug 2018
The knowledge on the realistic state of mixing of aerosols is inevitable for climate studies. Our paper unravels the existing uncertainties regarding the morphology and mixing state of aerosols, hitherto unexplained. To the best of our knowledge, this is a first-of-its kind study over the Indian region, coupling realistic aerosol observations, advanced spectroscopic, microscopic and image processing techniques on atmospheric aerosols at single particle resolution.
The knowledge on the realistic state of mixing of aerosols is inevitable for climate studies....