On the importance of non-ideal sulphate processing of multi-component aerosol haze over urban areas

Gumber, Siddharth; Ghosh, S.; Bera, Sudarsan; Prabhakaran, Thara

doi:10.1007/s00703-022-00877-7

Cited by 1 publication

(9 citation statements)

References 48 publications

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“…The standard deviations in the spectra are obtained from Ghosh et al (2007). Interestingly, the transient biomass loading covers the broadest range of aerosol particles of size – 0.1 to

10 μm

in agreement with other studies (Gumber et al, 2022; Gumber & Ghosh, 2022). Note the associated uncertainties in the number counts of transient biomass modes represented through error bars.…”

Section: Resultssupporting

confidence: 91%

“…A lognormal distribution was used to generate the particle size distribution (discussed in the next Section 3.1 under the sub‐heading ‘Size Separation Analysis’), assuming a constant density of the deposited BC matter (1350

kg / {normalm}^{3}

). A fuller procedure would involve Dynamic Light Scattering (DLS) characterisation of the collected particulates as discussed in Gumber and Ghosh (2022) and Gumber et al (2022); this was not possible because on‐site particle analysers were not available with the Tamil Nadu Pollution Control Board. However, a Java‐based image processing program, that is, ImageJ, is used for a preliminary size assessment of the collected particulates (ImageJ, 2011).…”

Section: Methodsmentioning

confidence: 99%

“…Fresh biomass emissions coated with such hydrophilic materials can serve as cloud condensation nuclei (CCN) and can modulate the extent of cloud cover (Dusek et al, 2006; Gumber et al, 2022; Henning et al, 2010; Oshima et al, 2009). This is now explored.…”

Section: Methodsmentioning

confidence: 99%

“…Since the soluble mass on the aerosol particle modulates the overall density (ρ t ) of the particles concerned, an accurate apportioning of ρ t is necessary (Ghosh et al, 2007;Gumber & Ghosh, 2022). Results from the parcel model simulations are shown for three levels of soluble sulphate content for the growth of transient biomass particles: 0.25the lower end of values observed, 0.5levels during a possible aggravated state, 0.75levels anticipated during the worst-case scenario (i.e., cases mediated by accidents).…”

Section: Transient Biomasscharacterisation In the Chemical Parcel Modelmentioning

confidence: 99%

“…However, over polluted urban conurbations, biomass smoke is a recurring aerosol mode that mixes with other background modes (Gumber & Ghosh, 2022). Recent research over another polluted Indian city, that is, Hyderabad, suggested that biomass emissions undergo nonideal heterogeneous sulphate accretion during repeated rounds of cloud processing such that the production of sulphate increases the water-soluble mass fraction of already existing biomass aerosols, making them even more hygroscopic (Gumber et al, 2022).…”

Section: Large Eddy Simulation (Les)mentioning

confidence: 99%

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How Asian slum emissions impact local microclimates in polluted air masses

Ghosh

Kumar

Gumber

et al. 2022

Atmospheric Science Letters

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Urban sprawl comprising densely populated slums over South Asian cities yields copious amounts of soot and black carbon from archaic cooking methods involving cow dung cakes and firewood, which remain afloat for over 10-12 h, enabling them to age in a sulphur rich environment. Not only are there toxicological concerns arising out of improper ventilation mechanisms, but there are also other concerns impacting the local microclimate. These emissions mix with other aerosol particles and, when conditions are favourable, are rendered partially soluble, enabling them to activate into cloud condensation nuclei. This study first yields a quantification of the soluble mass fraction and subsequently shows how aerosols from this local area source mix with background aerosol modes to perturb the local cloud microphysics over Chennai, a megacity in Southern India. On-site sampling was undertaken to find the mass concentrations of the collected deposits separately from cow dung and firewood fuel. Additional micro-physical attributes, including the morphological indentations that served as a receptacle to contain the accreted sulphate along with the particle size distribution were ascertained through Scanning Electron Microscopy. It is shown that accreted sulphate on carbonaceous particles facilitates CCN activation over the city. We show through large-eddy simulations (LES) that extensive slum emissions over the study region contribute to the observed local cloud cover and enhanced rain amounts over a densely built-up area housing the city's most vulnerable citizens.

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“…The standard deviations in the spectra are obtained from Ghosh et al (2007). Interestingly, the transient biomass loading covers the broadest range of aerosol particles of size – 0.1 to

10 μm

in agreement with other studies (Gumber et al, 2022; Gumber & Ghosh, 2022). Note the associated uncertainties in the number counts of transient biomass modes represented through error bars.…”

Section: Resultssupporting

confidence: 91%