Optical source apportionment of aqueous brown carbon (BrC) on a daytime and nighttime basis in the eastern Indo-Gangetic Plain (IGP) and insights from 13C and 15N isotopic signatures

Dey, Satyahari; Ghosh, Pronoy; Rawat, Prashant; Choudhary, Nikki; Rai, Ankita; Meena, Rohit; Mandal, T. K.; Mao, Jingying; Jia, Shiguo; Rastogi, Neeraj; Sharma, S.K.; Sarkar, Sayantan

doi:10.1016/j.scitotenv.2023.164872

Cited by 5 publications

(1 citation statement)

References 132 publications

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“…Several studies have reported ambient BrC absorption in the South Asian region (Dey et al, 2023;Sarin, 2013, 2014;Bikkina et al, 2020;Boreddy et al, 2021;Choudhary et 315 al., 2017Choudhary et 315 al., , 2018Choudhary et 315 al., , 2022Dasari et al, 2019;Dey et al, 2021;Kirillova et al, 2016 al., 2020;Rajeev et al, 2022;Rastogi et al, 2021;Rana et al, 2020;Shamjad et al, 2016bShamjad et al, , 2018, most climate models continue to consider weakly absorbing BrC absorption (Sand et al, 2021;Feng et al, 2013), invariant of sources and combustion conditions. Feng et al (2013) simulated global BrC absorption by using 2-to 5-fold weaker kBrC values than those observed 320 in our study, and they noted underestimation over South Asia owing to presence of strongly absorbing BrC.…”

Section: Spatial Differences In Kbrc365 and Wmentioning

confidence: 99%

Brownness of Organics in Anthropogenic Biomass Burning Aerosols over South Asia

Navinya,

Kapoor,

Anurag

et al. 2024

Preprint

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Abstract. In South Asia, biomass is burned for energy and waste disposal, producing brown carbon (BrC) aerosols whose climatic impacts are highly uncertain. To assess these impacts, a real-world understanding of BrC’s physio-optical properties is essential. For this region, the order-of-magnitude variability in BrC’s spectral refractive index as a function of particle volatility distribution is poorly understood. This leads to oversimplified model parameterization and subsequent underestimation of regional radiative forcing. Here we used the field-collected aerosol samples from major anthropogenic biomass activities to examine the methanol-soluble BrC optical properties. We show a strong relation between the absorption strength, wavelength dependence, and thermo-optical fractions of carbonaceous aerosols. Our observations show strongly absorbing BrC near the Himalayan foothills that may accelerate glacier melt, further highlighting the limitations of climate models where variable BrC properties are not considered. These findings provide crucial inputs for refining climate models and developing effective regional strategies to mitigate BrC.

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