Mineralogical diversity and internal mixing of dust with carbonaceous particles in wintertime Indo-Gangetic Plain haze
5 affiliations
- 1Environmental Molecular Sciences Laboratory
- 2Pacific Northwest National Laboratory
- 3Atmospheric and Earth Sciences Division
- 4University of Wyoming
- 5Michigan Technological University
Abstract
Wintertime haze in the Indo-Gangetic Plain (IGP) is driven by biomass burning, fossil fuel combustion, industrial emissions, and resuspended dust, yet the mineralogical diversity of individual dust particles and the physical properties of co-occurring carbonaceous aerosol remain poorly constrained. We characterize the elemental composition of mineral dust particles across seven size-resolved aerosol samples collected in January 2018 in the eastern IGP and investigate the thermal volatility of morphologically distinct carbonaceous particle types and the phase states based on the composition of co-occurring organic aerosol. Single-particle micro-spectroscopy analysis revealed predominantly Si-rich aluminosilicate dust substantially internally mixed with carbonaceous material, alongside an episodic enhancement of low-Si, low-Ca Fe-rich particles inconsistent with fly ash and suggestive of local Fe-oxide mineral sources. Microscopic imaging with in-situ heating showed that highly viscous tar balls were the least volatile, while low-viscosity particles with crystalline K-sulfate inclusions showed intermediate volatility, reflecting the thermal lability of inorganic sulfate phases. Furthermore, glass transition temperature estimates from high-resolution mass spectrometry analysis indicated that morning organic aerosol existed predominantly in semi-solid to solid phase states, shifting to semi-solid to liquid in the afternoon as relative humidity increased from 43% to 78%. These results highlight the mineralogical heterogeneity of IGP dust, the role of internal mixing in governing particle volatility, and the strong sensitivity of organic aerosol phase state to ambient humidity in this heavily polluted wintertime environment.
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BibTeX
@misc{bhotika2026mineralogical,
title = {{Mineralogical diversity and internal mixing of dust with carbonaceous particles in wintertime Indo-Gangetic Plain haze}},
author = {Harsh Bhotika and Amna Ijaz and Susan Mathai and Claudio Mazzoleni and Swarup China},
howpublished = {ChemRxiv},
year = {2026},
month = sep,
doi = {10.26434/chemrxiv.15008136/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008136/v1},
note = {CC BY-NC-ND},
}
RIS
TY - UNPB
TI - Mineralogical diversity and internal mixing of dust with carbonaceous particles in wintertime Indo-Gangetic Plain haze
AU - Harsh Bhotika
AU - Amna Ijaz
AU - Susan Mathai
AU - Claudio Mazzoleni
AU - Swarup China
PY - 2026
DA - 2026/09/01
PB - ChemRxiv
DO - 10.26434/chemrxiv.15008136/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008136/v1
AB - Wintertime haze in the Indo-Gangetic Plain (IGP) is driven by biomass burning, fossil fuel combustion, industrial emissions, and resuspended dust, yet the mineralogical diversity of individual dust particles and the physical properties of co-occurring carbonaceous aerosol remain poorly constrained. We characterize the elemental composition of mineral dust particles across seven size-resolved aerosol samples collected in January 2018 in the eastern IGP and investigate the thermal volatility of morphologically distinct carbonaceous particle types and the phase states based on the composition of co-occurring organic aerosol. Single-particle micro-spectroscopy analysis revealed predominantly Si-rich aluminosilicate dust substantially internally mixed with carbonaceous material, alongside an episodic enhancement of low-Si, low-Ca Fe-rich particles inconsistent with fly ash and suggestive of local Fe-oxide mineral sources. Microscopic imaging with in-situ heating showed that highly viscous tar balls were the least volatile, while low-viscosity particles with crystalline K-sulfate inclusions showed intermediate volatility, reflecting the thermal lability of inorganic sulfate phases. Furthermore, glass transition temperature estimates from high-resolution mass spectrometry analysis indicated that morning organic aerosol existed predominantly in semi-solid to solid phase states, shifting to semi-solid to liquid in the afternoon as relative humidity increased from 43% to 78%. These results highlight the mineralogical heterogeneity of IGP dust, the role of internal mixing in governing particle volatility, and the strong sensitivity of organic aerosol phase state to ambient humidity in this heavily polluted wintertime environment.
ER -