Water Soluble Ionic Species in Atmospheric Aerosols: Concentrations and Sources at Agra in the Indo-Gangetic Plain (IGP)

Aparna Satsangi; Tripti Pachauri; Vyoma Singla; Anita Lakhani; K. Maharaj Kumari

doi:10.4209/aaqr.2012.08.0227

Variation in carbonaceous and ionic species at a rural receptor location in the eastern Indo-Gangetic Plain

10.5194/egusphere-egu21-7205 ◽

2021 ◽

Author(s):

Bijay Sharma ◽

Anurag J. Polana ◽

Jingying Mao ◽

Shiguo Jia ◽

Sayantan Sarkar

Keyword(s):

Organic Carbon ◽

Forest Fires ◽

Ionic Species ◽

Water Soluble ◽

Photochemical Oxidation ◽

Carbonaceous Aerosol ◽

Charge Ratio ◽

Gangetic Plain ◽

Post Monsoon ◽

Indo Gangetic Plain

The Indo-Gangetic Plain (IGP) is one of the world&#8217;s most populated river basins housing more than 700 million people. Apart from being a major source region of aerosols, the IGP is affected by transported aerosols from the Thar Desert, forest-fires and open burning of crop waste from central India. Studies have been carried out to understand the aerosol chemical composition and optical properties in source regions of IGP but knowledge is severely lacking for receptor locations viz. eastern IGP (eIGP). To address this, the present study reports the seasonal variability of carbonaceous and ionic species in ambient PM2.5 from a rural receptor location (Mohanpur, West Bengal) along with insights on aerosol acidity, its neutralization and potential source regimes. A total of 88 PM2.5 samples collected during the summer, post-monsoon and winter seasons of 2018 were analyzed for SO42-, NO3-, Cl-, Na+, NH4+, K+, Ca2+, Mg2+, F-,PO43-, water-soluble organic carbon (WSOC), organic carbon (OC) and elemental carbon (EC) fractions. Sulfate, nitrate and ammonium (SNA) were the dominating ionic species throughout the seasons (67-86% out of the total ionic species measured). Significant positive Cl- depletion in summer (49&#177;20%) pointed towards influx of marine air while negative depletion in post-monsoon and winter suggested a biomass burning (BB) source, which was further supported by concentration-weighted trajectory analysis. Strong acidity was found to be highest during post-monsoon (141&#177;76 nmol m-3), followed by winter (117&#177;36 nmol m-3) and summer (40&#177;14 nmol m-3) with significant differences between summer and the other seasons. Neutralization factor (Nf) and equivalent charge ratio of cation to anion (RC/A) revealed that summertime aerosols were neutral in nature while those of post-monsoon and winter were comparatively acidic with NH4+ being the major neutralizing agent throughout the seasons. Correlations between WSOC and OC fractions (OC1, OC2, OC3 and OC4) suggested secondary formation of summertime WSOC (WSOC vs OC3: r=0.48, p<0.05) via photochemical oxidation of volatile organic carbons (VOCs) while that of post-monsoon (WSOC vs OC1, OC2, OC3: r=0.45-0.62, p<0.05) and winter (WSOC vs OC1, OC2, OC3: r=0.58-0.68, p<0.05), both primary and secondary pathways seem important. To elucidate the role of BB, we looked into the two components of EC i.e., char-EC (EC1-PC) and soot-EC (EC2+EC3). The percent contribution of char-EC to EC was 65&#177;17%, 90&#177;10% and 98&#177;1% during summer, post-monsoon and winter, respectively. Along with this, char-EC/soot-EC ratios of 2.3&#177;1.8, 17.6&#177;16.4 and 50.3&#177;18.6 during summer, post-monsoon and winter, respectively, and significant correlations of the same with the BB-tracer K+ (post-monsoon: r=0.78, p<0.001; winter: r=0.64, p<0.01) indicated the importance of BB emissions in constraining carbonaceous aerosol profiles during post-monsoon and winter.

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Characteristics, seasonality and sources of carbonaceous and ionic components in the tropical Indian aerosols

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-11-3937-2011 ◽

2011 ◽

Vol 11 (2) ◽

pp. 3937-3976 ◽

Cited By ~ 1

Author(s):

C. M. Pavuluri ◽

K. Kawamura ◽

S. G. Aggarwal ◽

T. Swaminathan

Keyword(s):

Organic Carbon ◽

Atmospheric Aerosols ◽

Atmospheric Transport ◽

Indian Subcontinent ◽

Ionic Species ◽

Water Soluble ◽

Carbonaceous Aerosols ◽

Mass Fractions ◽

High Concentrations ◽

Ionic Components

Abstract. To better characterize South and Southeast Asian aerosols, PM10 samples collected from tropical Chennai, India (13.04° N; 80.17° E) were analyzed for carbonaceous and water-soluble ionic components. Concentration ranges of elemental carbon (EC) and organic carbon (OC) were 2.4–14 μg m−3 and 3.2–15.6 μg m−3 in winter samples whereas they were 1.1–2.5 μg m−3 and 4.1–17.6 μg m−3 in summer samples, respectively. Concentration of secondary organic carbon (SOC) retrieved from EC-tracer method was 4.6 ± 2.8 μg m−3 in winter and 4.3 ± 2.8 μg m−3 in summer. SO42- (8.8 ± 2.5 μg m−3 and 4.1 ± 2.7 μg m−3 in winter and summer, respectively) was found as the most abundant ionic species (57% on average, n = 49), followed by NH4+ (15%) > NO3− > Cl− > K+> Na+ > Ca2+ > MSA− > Mg2+. The mass fractions of EC, organic matter (OM) and ionic species varied seasonally, following the air mass trajectories and corresponding source strength. Based on mass concentration ratios of selected components and relations of EC and OC to marker species, we found that biofuel/biomass burning is the major source of atmospheric aerosols in South and Southeast Asia. The high concentrations of SOC and WSOC/OC ratios (ave. 0.45; n = 49) as well as good correlations between SOC and WSOC suggest that the secondary production of organic aerosols during long-range atmospheric transport is also significant in this region. This study provides the baseline data of carbonaceous aerosols for southern part of the Indian subcontinent.

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Investigation of atmospheric aerosols over semi-urban and urban areas in Eastern Indo-Gangetic Plain: seasonal variability and source apportionment using PMF

10.5194/egusphere-egu21-14205 ◽

2021 ◽

Author(s):

Kanishtha Dubey ◽

Shubha Verma

Keyword(s):

Organic Carbon ◽

Biomass Burning ◽

Atmospheric Aerosols ◽

Urban Areas ◽

Relative Concentration ◽

Road Dust ◽

Water Soluble ◽

Carbonaceous Aerosols ◽

Gangetic Plain ◽

Brick Kilns

The study investigates the chemical composition and source of aerosol origin at a semi-urban (Kharagpur&#8211;Kgp) and urban (Kolkata&#8211;Kol) region during the period February 2015 to January 2016 and September 2010 to August 2011 respectively. Major water-soluble inorganic aerosols (WSII) were determined using Ion chromatography and carbonaceous aerosols (CA) using OC&#8211;EC analyser. A multivariate factor analysis Positive Matrix Factorization (PMF) was used in resolving source of aerosols at the study locations. Seasonal analysis of WSII at Kgp and Kol indicated relative dominance of calcium at both the places followed by sodium, chloride, and magnesium ions. Non-sea salt potassium (nss&#8211;K+), a biomass burning tracer was found higher at Kol than at Kgp. Sum of secondary aerosols sulphate (SO42-), nitrate (NO3-) and ammonium (NH4+) was higher at Kol than Kgp with relative concentration of SO42- being higher than NO3- at Kgp which was vice-versa at Kol. Examination of carbonaceous aerosols showed three times higher concentration of organic carbon (OC) than elemental carbon (EC) with monthly mean of OC/EC ratio > 2, indicating likely formation of secondary organic carbon formation. Seasonal influence of biomass burning inferred from nss&#8211;K+ (OC/EC) ratio relationship indicated dissimilarity in seasonality of biomass burning at Kgp (Kol). PMF resolved sources for Kgp constituted of secondary aerosol emissions, biomass burning, fugitive dust, marine aerosols, crustal dust and emissions from brick kilns while for Kol factors constituted of burning of waste, resuspended paved road dust, coal combustion, sea spray aerosols, vehicular emissions and biomass burning.

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Brown carbon in the continental outflow to the North Indian Ocean

Environmental Science Processes & Impacts ◽

10.1039/c9em00089e ◽

2019 ◽

Vol 21 (6) ◽

pp. 970-987 ◽

Cited By ~ 10

Author(s):

Srinivas Bikkina ◽

Manmohan Sarin

Keyword(s):

Indian Ocean ◽

Soluble Fraction ◽

North Indian Ocean ◽

Water Soluble ◽

Gangetic Plain ◽

Brown Carbon ◽

Water Soluble Fraction ◽

The North ◽

Continental Outflow ◽

Indo Gangetic Plain

In this paper, we synthesize the size distribution and optical properties of the atmospheric water-soluble fraction of light-absorbing organic carbon (brown carbon; BrC) in the continental outflow from the Indo-Gangetic Plain (IGP) in South Asia to the North Indian Ocean.

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Development of a Regression Model for Estimating Daily Radiative Forcing Due to Atmospheric Aerosols from Moderate Resolution Imaging Spectrometers (MODIS) Data in the Indo Gangetic Plain (IGP)

Atmosphere ◽

10.3390/atmos9100405 ◽

2018 ◽

Vol 9 (10) ◽

pp. 405 ◽

Cited By ~ 1

Author(s):

Shreemat Shrestha ◽

Murray Peel ◽

Graham Moore

Keyword(s):

Regression Model ◽

Water Vapour ◽

Atmospheric Aerosols ◽

Radiative Forcing ◽

Crop Production ◽

Atmospheric Water ◽

Gangetic Plain ◽

Atmospheric Water Vapour ◽

Station Data ◽

Indo Gangetic Plain

The assessment of direct radiative forcing due to atmospheric aerosols (ADRF) in the Indo Gangetic Plain (IGP), which is a food basket of south Asia, is important for measuring the effect of atmospheric aerosols on the terrestrial ecosystem and for assessing the effect of aerosols on crop production in the region. Existing comprehensive analytical models to estimate ADRF require a large number of input parameters and high processing time. In this context, here, we develop a simple model to estimate daily ADRF at any location on the surface of the IGP through multiple regressions of AErosol RObotic NETwork (AERONET) aerosol optical depth (AOD) and atmospheric water vapour using data from 2002 to 2015 at 10 stations in the IGP. The goodness of fit of the model is indicated by an adjusted R2 value of 0.834. The Jackknife method of deleting one group (station data) was employed to cross validate and study the stability of the regression model. It was found to be robust with an adjusted R2 fluctuating between 0.813 and 0.842. In order to use the year-round ADRF model for locations beyond the AERONET stations in the IGP, AOD, and atmospheric water vapour products from MODIS Aqua and Terra were compared against AERONET station data and they were found to be similar. Using MODIS Aqua and Terra products as input, the year-round ADRF regression was evaluated at the IGP AERONET stations and found to perform well with Pearson correlation coefficients of 0.66 and 0.65, respectively. Using ADRF regression model with MODIS inputs allows for the estimation of ADRF across the IGP for assessing the aerosol impact on ecosystem and crop production.

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Aerosol acidity and its neutralization in the eastern Indo-Gangetic Plain: implications for water-soluble organic carbon

10.5194/egusphere-egu2020-717 ◽

2020 ◽

Author(s):

Bijay Sharma ◽

Anuraag J. Polana ◽

Prashant Rawat ◽

Sayantan Sarkar

Keyword(s):

Receptor Site ◽

Water Soluble ◽

Dual Function ◽

Gangetic Plain ◽

Desert Dust ◽

Post Monsoon ◽

Aerosol Acidity ◽

Water Soluble Organic Carbon ◽

Soluble Organic Carbon ◽

Indo Gangetic Plain

Aerosol acidity plays an important role in influencing precipitation pH, which has impacts on the environment as well as human health. It also has significance in shaping aerosol chemistry, including the catalytic formation of water-soluble organic carbon (WSOC), which in turn affects the hygroscopicity of aerosols. Past studies on aerosol acidity in the Indian subcontinent, mostly conducted in biomass burning (BB) source regions in the northwestern and central Indo-Gangetic Plain (IGP) and in western India, have identified Ca2+ and Mg2+ sourced from desert dust to be the predominant neutralizing agents. However, the prevalence of desert dust decreases progressively along the IGP corridor and is potentially rendered insignificant in the eastern IGP (eIGP). As such, there exists a critical weakness in our understanding of the processes governing aerosol acidity and its neutralization in the eIGP. To address this, the present study reports the seasonal variability of ionic species, WSOC and associated aerosol acidity in ambient PM2.5 from a rural receptor site in the eIGP. To this end, a total of 88 PM2.5 samples collected during the summer, post-monsoon and winter seasons of 2018 were analyzed for SO42-, NO3-, Cl-, Na+, NH4+, K+, Ca2+, Mg2+, F-, PO43- and WSOC, followed by estimation of strong acidity. Across all seasons, the aerosol phase was dominated by SO42-, NH4+ and NO3-, with values increasing by factors of 1.8-1.9, 1.4-2.9 and 1.8-11, respectively, for the regional BB-dominated post-monsoon and winter seasons as compared to summer. Significant positive Cl- depletion in summer pointed towards the influx of marine air while negative depletion in post-monsoon and winter suggested a BB source, which was further supported by concentration-weighted trajectory analysis. The averaged pH of the aerosol extract decreased progressively from summer (5.5&#177;0.4) to winter (4.5&#177;0.2). NH4+ was observed to be the major acid-neutralizing agent across all seasons, with dust-derived Ca2+ and Mg2+ playing only minor roles. In general, WSOC formation is known to be catalyzed by the presence of excess acidity; however, during winter, it appeared that the regional transport of organic acids in the BB plume contributed to aerosol acidity at this receptor site (r=0.92; p<0.01 for WSOC and H+). BB-derived K+ appeared to perform a dual function of neutralizing acidity as well as producing it via reactions with WSOC during atmospheric transport. The wintertime acidity was also strongly governed by aerosol NO3- sourced from BB emissions and possibly accentuated via nighttime atmospheric chemistry at lower ambient temperatures, resulting in the formation of haze. These observations of the NO3- and WSOC-driven wintertime acidity, the dual function of K+ and the dominant role of NH4+ in neutralization points to complex atmospheric processing of the IGP outflow during its transport to the eastern end of the corridor, which warrants further investigation.

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Atmospheric aerosols properties over Indo-Gangetic Plain: A trend analysis using ground – truth AERONET data for the year 2009 - 2017

Advances in Space Research ◽

10.1016/j.asr.2021.12.052 ◽

2022 ◽

Author(s):

Akhilesh Kumar ◽

Vineet Pratap ◽

Sarvan Kumar ◽

A.K. Singh

Keyword(s):

Trend Analysis ◽

Atmospheric Aerosols ◽

Ground Truth ◽

Gangetic Plain ◽

Indo Gangetic Plain

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Optical and chemical properties of wintertime light-absorbing aerosols in the eastern Indo-Gangetic Plain, India

10.5194/egusphere-egu2020-655 ◽

2020 ◽

Author(s):

Supriya Dey ◽

Archita Rana ◽

Prashant Rawat ◽

Sayantan Sarkar

Keyword(s):

Organic Carbon ◽

Light Absorption ◽

Mass Concentration ◽

Chemical Properties ◽

Water Soluble ◽

Chemical Extraction ◽

Aerosol Formation ◽

Gangetic Plain ◽

Indo Gangetic Plain ◽

And Chemical Properties

Light-absorbing carbonaceous aerosols such as black and brown carbon (BC and BrC) and humic-like substances (HULIS) have pronounced effects on the earth&#8217;s radiative balance and tropospheric photochemistry. In India, large heterogeneities exist for BC and organic carbon (OC) emission inventories, which necessitates regionally-representative ground-based measurements. Such measurements are spatially scattered for BC, rare for BrC and non-existent for HULIS. This severely limits a robust understanding of the optical and chemical properties of these aerosols, and consequently, their climate effects. To address this issue, the present study reports optical and chemical properties of wintertime (December 2018-February 2019) BC, BrC and HULIS at a rural receptor site in the highly polluted eastern Indo-Gangetic Plain (IGP), India. A 7 wavelength aethalometer was deployed to measure time-resolved BC mass concentration, and absorption coefficients (babs) and Angstrom exponent (AE) of BrC. Separation of aqueous and organic BrC (BrCaq and BrCorg) and HULIS fractions via a multi-step chemical extraction procedure followed by optical measurements (UV-Vis, fluorescence and FT-IR), and supplementary measurements of OC, water-soluble organic carbon (WSOC) and ionic species led to better insights into the potential chromophore composition and their relative importance in constraining aerosol optical properties.The daily averaged BC mass concentration was 15.4&#177;9.5 &#956;g m-3 during winter, where the biomass burning (BB) contribution was 25&#177;5%. The diurnal profile of BCBB and BrC light absorption coefficient (babs_BrC) showed a prominent morning peak (0700-0800 H) characterized by mixed fossil fuel and biofuel emission and a gradual increase towards night due to enhanced primary BB emission from cooking activities and lowering of the mixing depth. The regionally transported BB plume from northwestern IGP contributed substantial BC and BrC to this receptor location in the eastern end of the corridor, which was supported by concentration-weighted air mass trajectories (CWTs).The BrCorg light absorption at 365 nm (babs_BrC_org) was almost 2 times compared to that of BrCaq (babs_BrC_aq) (36&#177;7.1 vs 18.3&#177;4.3 Mm-1), which suggested a dominance of non-polar polyconjugated BrC chromophores. This was also supported by the increasing trend of water-insoluble BrC from 49&#177;10% at 365 nm to 64&#177;21% at 550 nm, with averaged contributions of 49&#177;8% at 300-400 nm and 67&#177;9% at 400-550 nm, respectively. A strong correlation between WSOC and NO3- (r=0.78, p<0.01) and WSOC and NH4+ (r=0.63, p<0.01) indicated the possibility of nighttime secondary organic aerosol formation. A prominent fluorescence peak at ~409 nm for BrCaq confirmed the presence of HULIS, and babs_BrC_aq was dominated by the low-polarity HULIS-n fraction. AE of individual HULIS fractions increased by 7-36% towards the more polar HULIS-a and highly-polar water-soluble organic matter (HPWSOM) compared to the less polar HULIS-n for the 300-700 nm range. Distinct FTIR peaks at 3400 cm-1, 1710 cm-1 and 1643 cm-1 suggested abundance of C-H, C=O and C=C functional groups, respectively, in the BrC chromophores. Overall, it appeared that the regionally transported BB plume significantly enriches BrC and HULIS in the eastern part of the IGP corridor. &#160;&#160;

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Supplementary material to "Organic molecular tracers in the atmospheric aerosols from Lumbini, Nepal, in the northern Indo-Gangetic Plain: Influence of biomass burning"

10.5194/acp-2016-1176-supplement ◽

2017 ◽

Author(s):

Xin Wan ◽

Shichang Kang ◽

Quanlian Li ◽

Dipesh Rupakheti ◽

Qianggong Zhang ◽

...

Keyword(s):

Biomass Burning ◽

Atmospheric Aerosols ◽

Gangetic Plain ◽

Supplementary Material ◽

Molecular Tracers ◽

Indo Gangetic Plain

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Impact of continental outflow on chemistry of atmospheric aerosols over tropical Bay of Bengal

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-11-20667-2011 ◽

2011 ◽

Vol 11 (7) ◽

pp. 20667-20711 ◽

Cited By ~ 8

Author(s):

B. Srinivas ◽

A. Kumar ◽

M. M. Sarin ◽

A. K. Sudheer

Keyword(s):

Atmospheric Aerosols ◽

Bay Of Bengal ◽

Agricultural Waste ◽

Enrichment Factors ◽

Water Soluble ◽

Anthropogenic Sources ◽

Gangetic Plain ◽

Continental Outflow ◽

The Impact ◽

Tropical Bay

Abstract. The continental outflow from Indo-Gangetic Plain and south-east Asia dominates the widespread dispersal of pollutants over tropical Bay of Bengal (BoB) during the late NE-monsoon (January–March). It is thus pertinent to assess the impact on marine atmospheric boundary layer of BoB. The chemical data, based on analyses of size-segregated (PM2.5 and PM10) aerosols, suggest the dominance of nss-SO42− (range: 1.3 to 28 μg m−3) in PM2.5. Almost all SO42− is of anthropogenic origin and accounts for as much as 65 % of the water-soluble inorganic constituents. The impact of anthropogenic sources is further evident from the widespread depletion of chloride (range: 40 to 100 %) compared to sea-salt composition. The carbonaceous species (EC and OC) contribute nearly 25 % to PM2.5; and significant linear relationship with K+ suggests biomass burning as their dominant source (biofuels and agricultural waste). The enhancement in the fractional solubility of aerosol Fe, as assessed in PM2.5, re-emphasizes the impact of combustion sources (biomass and fossil-fuel) and chemical processing (of dust) during the long-range transport. The high enrichment factors of heavy metals (Pb and Cd) further demonstrate the influence of pollution sources on the chemistry of MABL. The downwind transport of pollutants and exchange across air-sea interface can, thus, have profound impact on the ocean surface biogeochemistry.

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