Assessment of submicron aerosol liquid water content and mass-based growth factors in South Asian outflow over the Indian Ocean

The Science of The Total Environment, Год журнала: 2023, Номер 901, С. 166461 - 166461

Опубликована: Авг. 20, 2023

Язык: Английский

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Seasonally optimized calibrations improve low-cost sensor performance: long-term field evaluation of PurpleAir sensors in urban and rural India

Atmospheric measurement techniques, Год журнала: 2023, Номер 16(19), С. 4357 - 4374

Опубликована: Окт. 5, 2023

Abstract. Lower-cost air pollution sensors can fill critical quality data gaps in India, which experiences very high fine particulate matter (PM2.5) but has sparse regulatory monitoring. Challenges for low-cost PM2.5 India include high-aerosol mass concentrations and pronounced regional seasonal gradients aerosol composition. Here, we report on a detailed long-time performance evaluation of popular sensor, the Purple Air PA-II, at multiple sites India. We established three distinct across land use categories population density extremes (in urban Delhi rural Hamirpur north Bengaluru south India), where collocated PA-II model with reference beta attenuation monitors. evaluated uncalibrated sensor data, then developed, optimized, calibration models using comprehensive feature selection process view to reproducibility Indian context. assessed spatial transferability schemes, is especially important because paucity instrumentation. Without calibration, was moderately correlated signal (R2 = 0.55–0.74) inaccurate (NRMSE ≥ 40 %). Relative parsimonious annual improved PurpleAir (PA) all (cross-validated NRMSE 20 %–30 %; R2 0.82–0.95), greatly reduced diurnal biases. Because properties meteorology vary regionally, form these long-term differed among our sites, suggesting that local calibrations are desirable when possible. Using moving-window found seasonally specific information improves relative static model, while short-term generally does not transfer reliably other seasons. Overall, find provide reliable better than ±25 % precision accuracy paired rigorous scheme accounts seasonality

Язык: Английский

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Significant chlorine emissions from biomass burning affect the long-term atmospheric chemistry in Asia

National Science Review, Год журнала: 2024, Номер 11(9)

Опубликована: Авг. 13, 2024

Biomass burning (BB) is a major source of trace gases and particles in the atmosphere, influencing air quality, radiative balance, climate. Previous studies have mainly focused on BB emissions carbon nitrogen species with less attention chlorine. Reactive chlorine chemistry has significant effects atmospheric quality. However, quantitative information from BB, particularly long-term trend associated impacts, limited both regional global scales. Here, we report (2001-2018) high-resolution emission inventory for chlorine-containing compounds (HCl, chloride, CH

Язык: Английский

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Impact of nylon and teflon filter media on the sampling of inorganic aerosols over a high altitude site

Environmental Advances, Год журнала: 2023, Номер 12, С. 100373 - 100373

Опубликована: Май 1, 2023

Water-soluble inorganic aerosols constitute major fraction of PM2.5 play an important role in the Earth-climate system and affect adversely on human health. However, their measurement accuracy highly vary depending choice filter media denuder usage. In most cases, denuders are either not deployed or use is partially limited to removal certain gases. Therefore, understand impact undenuded ambient sampling type depositional loading water-soluble aerosols; three (1 teflon 2 nylon based) different pore-sized was carried at a high altitude location Western Ghats during winter season. Results show gas-phase adsorption higher than hydrophobic membrane. Decreased pH overall increased conductivity observed suggested acidic species. Nylon showed increasing ionic concentration order followed Mg2+Na+>Ca2+>K+. ISORROPIA-II derived NH3 Cl(g) found teflon. Poor correlation between X-ray Fluorescence (XRF) Ion Chromatography (IC) crustal specie (Ca) showing off-set both results, however, positively correlated for secondary species (Cl−, NH4+, NO3+ SO42−). Neutralization efficiency revealed NH4+ as main neutralizer SO42− whereas teflon, Ca2+ be neutralizing component. On comparing Na+ Cl+ effects over neutralization, extensive prevalence non-seasalt sources. Concentration weighted trajectory analysis minus indicated excess semi-volatiles NO3− NH4+) mostly driven by oxidation precursory gases originating from local nearby coastal cities, non-refractory ultrafine mode inland majorly polluted North Indian region.

Язык: Английский

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Aerosol liquid water in PM2.5 and its roles in secondary aerosol formation at a regional site of Yangtze River Delta

Journal of Environmental Sciences, Год журнала: 2023, Номер 138, С. 684 - 696

Опубликована: Май 4, 2023

Язык: Английский

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