Browsing by Author "Kirpa Ram"

Now showing 1 - 20 of 69

Accumulation of Atmospheric Mercury in Glacier Cryoconite over Western China
(American Chemical Society, 2019) Jie Huang; Shichang Kang; Ming Ma; Junming Guo; Zhiyuan Cong; Zhiwen Dong; Runsheng Yin; Jianzhong Xu; Lekhendra Tripathee; Kirpa Ram; Feiyue Wang
Cryoconite is a granular aggregate, comprised of both mineral and biological material, and known to accumulate atmospheric contaminants. In this study, cryoconite was sampled from seven high-elevation glaciers in Western China to investigate the spatial and altitudinal patterns of atmospheric mercury (Hg) accumulation in the cryoconite. The results show that total Hg (HgT) concentrations in cryoconite were significant with relatively higher Hg accumulation in the southern glaciers (66.0 ± 29.3 ng g-1), monsoon-influenced regions, than those in the northern glaciers (42.5 ± 20.7 ng g-1), westerlies-influenced regions. The altitudinal profile indicates that HgT concentrations in the northern glaciers decrease significantly with altitude, while those in the southern glaciers generally increase toward higher elevations. Unexpectedly high accumulation of methyl-Hg (MeHg) with an average of 1.0 ± 0.4 ng g-1 was also detected in the cryoconite samples, revealing the surface of cryoconite could act as a potential site for Hg methylation in alpine environments. Our preliminary estimate suggests a storage of ?34.3 ± 17.4 and 0.65 ± 0.28 kg of HgT and MeHg from a single year of formation process in the glacier cryoconite. Therefore, glacier cryoconite could play an important role in Hg storage and transformation, which may result in downstream effects on glacier-fed ecosystems under climate warming scenario. © 2019 American Chemical Society.
Aerosol chemical characterization and role of carbonaceous aerosol on radiative effect over Varanasi in central Indo-Gangetic Plain
(Elsevier Ltd, 2016) S. Tiwari; U.C. Dumka; D.G. Kaskaoutis; Kirpa Ram; A.S. Panicker; M.K. Srivastava; Shani Tiwari; S.D. Attri; V.K. Soni; A.K. Pandey
This study investigates the chemical composition of PM10 aerosols at Varanasi, in the central Indo-Gangetic Plain (IGP) during April to July 2011, with emphasis on examining the contribution of elemental carbon (EC) to the estimates of direct aerosol radiative effect (DARE). PM10 samples are analysed for carbonaceous aerosols (Organic Carbon, OC and EC) and water-soluble ionic species (WSIS: Cl-, SO42-, NO3-, PO42- NH4+, Na+, K+, Mg2+ and Ca2+) and several diagnostic ratios (OC/EC, K+/EC, etc) have been also used for studying the aerosol sources at Varanasi. PM10 mass concentration varies between 53 and 310 μgm-3 (mean of 168 ± 73 μgm-3), which is much higher than the National and International air quality standards. The OC mass concentration varies from 6 μg m-3 to 24 μg m-3 (mean of 12 ± 5 μg m-3; 7% of PM10 mass), whereas EC ranges between 1.0 and 14.3 μg m-3 (4.4 ± 3.9 μg m-3; ~3% of PM10 mass). The relative low OC/EC of 3.9 ± 2.0 and strong correlation (R2 = 0.82) between them suggest the dominance of primary carbonaceous aerosols. The contribution of WSIS to PM10 is found to be ~12%, out of which ~57% and 43% are anions and cations, respectively. The composite DARE estimates via SBDART model reveal significant radiative effect and atmospheric heating rates (0.9-2.3 Kday-1). Although the EC contributes only ~3% to the PM10 mass, its contribution to the surface and atmospheric forcing is significantly high (37-63% and 54-77%, respectively), thus playing a major role in climate implications over Varanasi. © 2015 Elsevier Ltd.
Aerosol Properties Over Tibetan Plateau From a Decade of AERONET Measurements: Baseline, Types, and Influencing Factors
(Blackwell Publishing Ltd, 2019) Manisha Pokharel; Jie Guang; Bin Liu; Shichang Kang; Yaoming Ma; Brent N. Holben; Xiang'ao Xia; Jinyuan Xin; Kirpa Ram; Dipesh Rupakheti; Xin Wan; Guangming Wu; Hemraj Bhattarai; Chuanfeng Zhao; Zhiyuan Cong
In this study, a decade long measurement of aerosol optical properties at two AERONET stations (Nam Co during 2006–2016 and QOMS during 2009–2017) in the Tibetan Plateau (TP), a region sensitive to climate change and human perturbation, is presented. The baseline value of aerosol optical depth (AOD) was 0.029 and 0.027 at Nam Co and QOMS, respectively, which are comparable to or even lower than those at some Arctic and remote ocean locations. The seasonality of AOD values were the order of spring > summer > winter > autumn. Based on AOD and Ångström exponent (α), major aerosol types over the TP were further identified as continental background, biomass burning, and dust. Although continental background aerosol was the main feature in remote areas of TP, biomass burning plumes frequently occurred, especially during spring (March–April). In one of such biomass burning event in April 2014, MODIS observations demonstrated that intensive open fires occurred in South Asia, covering the foothills of Himalayas and Indo-Gangetic Plain. The air mass back trajectories and CALIOP observations further revealed that biomass burning plume could be uplifted to higher altitudes and reach the Himalayas. Moreover, an occasional dust event detected in April 2008 over the TP demonstrated that the dust from Taklamakan Desert may impact the main body of TP episodically, although the local dust from the inside of TP cannot be excluded and warrants further study. ©2019. American Geophysical Union. All Rights Reserved.
Anthropogenic and natural drivers of seesaw-like spatial patterns in precipitation mercury over western China
(Elsevier Ltd, 2022) Jie Huang; Shichang Kang; Long Wang; Kaiyun Liu; Kirpa Ram; Mika Sillanpää; Wenjun Tang; Junming Guo; Qianggong Zhang; Ming Ma; Lekhendra Tripathee; Feiyue Wang
Investigation of mercury (Hg) from atmospheric precipitation is important for evaluating its ecological impacts and developing mitigation strategies. Western China, which includes the Tibetan Plateau and the Xinjiang Uyghur Autonomous Region, is one of the most remote region in the world and is understudied in regards to Hg precipitation. Here we report seesaw-like patterns in spatial variations of precipitation Hg in Western China, based on Hg speciation measurements at nine stations over this remote region. The Hg fraction analyzed included total Hg (HgT), particulate-bound Hg (HgP) and methylmercury (MeHg). Spatially, HgT concentrations and percentage of HgP in precipitation were markedly greater in the westerlies domain than those in the monsoon domain, but the higher wet HgT flux, MeHg concentration and percentage of MeHg in precipitation mainly occurred in the monsoon domain. Similar spatial patterns of wet Hg deposition were also obtained from GEOS-Chem modeling. We show that the disparity of anthropogenic and natural drivers between the two domains are mainly responsible for this seesaw-like spatial patterns of precipitation Hg in Western China. Our study may provide a baseline for assessment of environmental Hg pollution in Western China, and subsequently assist in protecting this remote alpine ecosystem. © 2022 Elsevier Ltd
Application of water quality index (WQI) and statistical techniques to assess water quality for drinking, irrigation, and industrial purposes of the Ghaghara River, India
(Elsevier B.V., 2023) Nirdesh Kumar Ravi; Pawan Kumar Jha; Kriti Varma; Piyush Tripathi; Sandeep Kumar Gautam; Kirpa Ram; Manish Kumar; Vijay Tripathi
Ghaghara river samples were analysed to determine their quality and fitness for household, agriculture, and industrial use. In Ghaghara River, the cations were present in order of Ca2+ > Mg2+ > Na+ > K +, and anions were in order of HCO3– > SO42− > Cl− > NO3– > F−. Gibbs's diagram indicated that carbonate and silicate weathering significantly influence the Ghaghara River ion chemistry. Piper trilinear diagrams indicated that Ca2++ Mg2+ exceeded the Na++ K +, and anions of weak acids dominated over the anions of strong acids, indicating Ca-HCO3 type of water. Based on the WQI values, the water quality class varied from 'unsuitable for drinking' to 'excellent' quality, and the parameter of concern was pH and fluoride ion concentration as they exceeded their permissible limits in the post-monsoon season, thereby negatively affecting the WQI values to unsuitable category. The computed value of the agriculture indices, including the Sodium absorption ratio (SAR), Sodium percentage (Na %), Kelly ratio (KR), Permeability Index (PI) value, Magnesium absorption ratio (MAR), and Potential salinity (PS), indicated that water quality was suitable for agriculture use. The Langelier Saturation Index (LSI) values indicated that 39% of the collected samples were unsuitable due to scale formation problems. Ryznar Stability Index (RSI) values indicated that the water of the Ghaghara River is corrosive and unsuitable for industrial use. © 2023 The Author(s)
Aromatic acids as biomass-burning tracers in atmospheric aerosols and ice cores: A review
(Elsevier Ltd, 2019) Xin Wan; Kimitaka Kawamura; Kirpa Ram; Shichang Kang; Mark Loewen; Shaopeng Gao; Guangming Wu; Pingqing Fu; Yanlin Zhang; Hemraj Bhattarai; Zhiyuan Cong
Biomass burning (BB) is one of the largest sources of carbonaceous aerosols with adverse impacts on air quality, visibility, health and climate. BB emits a few specific aromatic acids (p-hydroxybenzoic, vanillic, syringic and dehydroabietic acids) which have been widely used as key indicators for source identification of BB-derived carbonaceous aerosols in various environmental matrices. In addition, measurement of p-hydroxybenzoic and vanillic acids in snow and ice cores have revealed the historical records of the fire emissions. Despite their uniqueness and importance as tracers, our current understanding of analytical methods, concentrations, diagnostic ratios and degradation processes are rather limited and scattered in literature. In this review paper, firstly we have summarized the most established methods and protocols for the measurement of these aromatic acids in aerosols and ice cores. Secondly, we have highlighted the geographical variability in the abundances of these acids, their diagnostic ratios and degradation processes in the environments. The review of the existing data indicates that the concentrations of aromatic acids in aerosols vary greatly with locations worldwide, typically more abundant in urban atmosphere where biomass fuels are commonly used for residential heating and/or cooking purposes. In contrast, their concentrations are lowest in the polar regions which are avoid of localized emissions and largely influenced by long-range transport. The diagnostic ratios among aromatic acids can be used as good indicators for the relative amounts and types of biomass (e.g. hardwood, softwood and herbaceous plants) as well as photochemical oxidation processes. Although studies suggest that the degradation processes of the aromatic acids may be controlled by light, pH and hygroscopicity, a more careful investigation, including closed chamber studies, is highly appreciated. © 2019 Elsevier Ltd; Current research trends on aromatic acids as biomass burning tracers were comprehensively reviewed. © 2019 Elsevier Ltd
Atmospheric carbonaceous aerosols from Indo-Gangetic Plain and Central Himalaya: Impact of anthropogenic sources
(Academic Press, 2015) Kirpa Ram; M.M. Sarin
In the present-day scenario of growing anthropogenic activities, carbonaceous aerosols contribute significantly (~20-70%) to the total atmospheric particulate matter mass and, thus, have immense potential to influence the Earth's radiation budget and climate on a regional to global scale. In addition, formation of secondary organic aerosols is being increasingly recognized as an important process in contributing to the air-pollution and poor visibility over urban regions. It is, thus, essential to study atmospheric concentrations of carbonaceous species (EC, OC and WSOC), their mixing state and absorption properties on a regional scale. This paper presents the comprehensive data on emission sources, chemical characteristics and optical properties of carbonaceous aerosols from selected urban sites in the Indo-Gangetic Plain (IGP) and from a high-altitude location in the central Himalaya. The mass concentrations of OC, EC and WSOC exhibit large spatio-temporal variability in the IGP. This is attributed to seasonally varying emissions from post-harvest agricultural-waste burning, their source strength, boundary layer dynamics and secondary aerosol formation. The high concentrations of OC and SO42-, and their characteristic high mass scattering efficiency, contribute significantly to the aerosol optical depth and scattering coefficient. This has implications to the assessment of single scattering albedo and aerosol radiative forcing on a regional scale. © 2014 Elsevier Ltd.
Atmospheric Microplastics: Perspectives on Origin, Abundances, Ecological and Health Risks
(Springer Science and Business Media Deutschland GmbH, 2023) Shivali Gupta; Rakesh Kumar; Akanksha Rajput; Ruby Gorka; Antima Gupta; Nazuk Bhasin; Sudesh Yadav; Anju Verma; Kirpa Ram; Madulika Bhagat
Microplastic (MP) pollution has aroused a tremendous amount of public and scientific interest worldwide. MPs are found widely ranging from terrestrial to aquatic ecosystems primarily due to the over-exploitation of plastic products and unscientific disposal of plastic waste. There is a large availability of scientific literature on MP pollution in the terrestrial and aquatic ecosystems, especially the marine environments; however, only recently has greater scientific attention been focused on the presence of MPs in the air and its retrospective health implications. Besides, atmospheric transport has been reported to be an important pathway of transport of MPs to the pristine regions of the world. From a health perspective, existing studies suggest that airborne MPs are priority pollutant vectors, that may penetrate deep into the body through inhalation leading to adverse health impacts such as neurotoxicity, cancer, respiratory problems, cytotoxicity, and many more. However, their effects on indoor and outdoor air quality, and on human health are not yet clearly understood due to the lack of enough research studies on that and the non-availability of established scientific protocols for their characterization. This scientific review entails important information concerning the abundance of atmospheric MPs worldwide within the existing literature. A thorough comparison of existing sampling and analytical protocols has been presented. Besides, this review has unveiled the areas of scientific concern especially air quality monitoring which requires immediate attention, with the information gaps to be filled have been addressed. © 2023, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.
Atmospheric phosphorus and its geochemical cycling: Fundamentals, progress, and perspectives
(Elsevier B.V., 2023) Xing Diao; David Widory; Kirpa Ram; Lekhendra Tripathee; Srinivas Bikkina; Kimitaka Kawamura; Shaopeng Gao; Xin Wan; Guangming Wu; Qiaomin Pei; Xiaoping Wang; Zhiyuan Cong
Phosphorus (P) is an essential macronutrient for all organisms that can be redistributed between terrestrial and oceanic systems via atmospheric emission, transport, transformation, and deposition. Moreover, since natural P mobilization from the lithosphere to ecosystems is a relatively slow process, the role of atmospheric P seems to play an important role in its cycling. This paper provides a comprehensive review of the analytical methods used for characterizing atmospheric P species and the methods used for identifying P sources (e.g., oxygen stable isotope compositions of phosphate, δ18OP) discussing their respective suitability, advantages, and limitations. While at a regional scale δ18OP of atmospheric P are generally source-specific, at a more global scale these isotope compositions tend to overlap between sources, rendering their tracer potential more difficult. Furthermore, various sources of atmospheric P and their fluxes are compiled, and the potential uncertainties in the estimates of their respective contributions are reviewed, which suggest that more model inter-comparations, parameter optimizations, and field observations are still needed. Moreover, we summarize the long-range transport process controlling P atmospheric dispersion at various scales (focusing on dust and biomass burning). In addition, the transformation mechanism, especially acid dissolution, that modifies the P cycle during its residence time in the atmosphere is depicted. Finally, we propose that land cover may be a potential key control to the atmospheric P deposition rate based on the critical analysis of previously published rates. This review allows us to ultimately propose key recommendations for fostering future research on P geochemical cycling. © 2023
Atmospheric wet deposition of major ionic constituents and inorganic nitrogen in Bangladesh: Implications for spatiotemporal variation and source apportionment
(Elsevier Ltd, 2021) Subash Adhikari; Fan Zhang; Namita Paudel Adhikari; Chen Zeng; Ramesh Raj Pant; Kirpa Ram; Yongqin Liu; Nasir Ahmed; Jie Xu; Lekhendra Tripathee; Qianggong Zhang; Md. Abdul Quaiyum Bhuiyan; Md. Ariful Ahsan
The quantitative and qualitative characterization of ions and inorganic nitrogen in precipitation assists in understanding the accompanying sources and chemistry of regional precipitation. A total of 212 event-based precipitation samples were collected from four sites in Bangladesh in 2017 to investigate the physicochemical characteristics, sources, and deposition of atmospheric ionic constituents and inorganic nitrogen. During the entire monitoring period, 5.7% of the total samples were acidic (i.e., pH < 5.6), indicating that Bangladesh does not suffer severely from acid rain. The electrical conductivity (EC) and total dissolved solids (TDS) values indicate the inverse relationship between the amount of precipitation on the spatiotemporal scale. Ca2+ was the dominant neutralizing factor at four sites, which was demonstrated by the equivalent ratio of the neutralization potential to the acidifying potential and fractional acidity. Moreover, it had the highest volume-weighted mean concentration of all the sites, validating the calcareous nature of the soil aerosolized into the atmosphere. Distinct seasonality was observed for the majority of the ions with higher concentrations in the non-monsoon climate. Sea salt species displayed the pattern of Satkhira > Cox's Bazar > Dinajpur > Sylhet, whereas the anthropogenic species exhibited the order of Dinajpur > Satkhira > Sylhet > Cox's Bazar, underlining the local and regional impacts of these species in Bangladesh. Based on the source apportionment, the sources were categorized as marine (Na+ and Cl−), terrigenous (Ca2+, Mg2+, and HCO3−), fossil fuel combustion (NO3− and SO42−), agriculture (NH4+), and biomass burning (K+). The Cl− in Sylhet and Satkhira suggests additional sources associated with anthropogenic activities. The back-trajectory analyses and the National Centers for Environmental Prediction's final (NCEP FNL) datasets illustrate the presence of significantly diverse air masses with contributions from various sources in the monsoon and non-monsoon climates. Both the amount of precipitation and the ionic quantity governs the fluxes in Bangladesh. The Na+ % and SAR lie under the safe category suggesting a good precipitation water quality for agriculture and soil in Bangladesh, while the deposition of inorganic nitrogen has resulted in a value above the threshold line (10 kg ha−1 y−1). Thus, this study conveys a comprehensive picture of the ionic composition, providing a baseline dataset to assess the atmospheric environment in this lowland region. © 2020 Elsevier B.V.
Attributing Atmospheric Phosphorus in the Himalayas: Biomass Burning vs Mineral Dust
(American Chemical Society, 2024) Xing Diao; David Widory; Kirpa Ram; Enzai Du; Xin Wan; Shaopeng Gao; Qiaomin Pei; Guangming Wu; Shichang Kang; Zhong Wang; Xiaoping Wang; Zhiyuan Cong
Atmospheric phosphorus is a vital nutrient for ecosystems whose sources and fate are still debated in the fragile Himalayan region, hindering our comprehension of its local ecological impact. This study provides novel insights into atmospheric phosphorus based on the study of total suspended particulate matter at the Qomolangma station. Contrary to the prevailing assumptions, we show that biomass burning (BB), not mineral dust, dominates total dissolved phosphorus (TDP, bioavailable) deposition in this arid region, especially during spring. While total phosphorus is mainly derived from dust (77% annually), TDP is largely affected by the transport of regional biomass-burning plumes from South Asia. During BB pollution episodes, TDP causing springtime TDP fluxes alone accounts for 43% of the annual budget. This suggests that BB outweighs dust in supplying bioavailable phosphorus, a critical nutrient, required to sustain Himalayas’ ecological functions. Overall, this first-hand field evidence refines the regional and global phosphorus budget by demonstrating that BB emission, while still unrecognized, is a significant source of P, even in the remote mountains of the Himalayas. It also reveals the heterogeneity of atmospheric phosphorus deposition in that region, which will help predict changes in the impacted ecosystems as the deposition patterns vary. © 2023 American Chemical Society.
Bioaerosol emissions from solid waste processing facilities at urban environment and their impact on human health
(Elsevier B.V., 2025) Yogesh Kumar Vishwakarma; Neelmani Bhardwaj; Kirpa Ram; Mukunda Madhab Gogoi; Tirthankar Banerjee; Manoranjan Mohanty; R. S. Singh
Waste management is one of the challenging issues in developing countries because of indiscriminate urbanization, huge population growth coupled with insufficient technology to manage it. The processing of waste and producing manure are good techniques for solid waste management. This study shows that during waste processing such as loading and unloading, sorting, mixing and leachate treatment, several types of bioaerosols, both bacterial and fungal, are emitted to the atmosphere. Here, both fungal and bacterial bioaerosol concentration near a waste processing facility is reported with metagenomic analysis and health assessment. Average bacterial bioaerosol concentration was noted to be 2979 ± 544 CFU/m3, whereas the fungal bioaerosol concentration was 2288 ± 1128 CFU/m3 at the waste processing site. Size distribution shows that the concentration of bacterial bioaerosol was mostly in the finer range (0.65–1.1 μm) while the fungal concentration was highest in the coarse size (between 3.3 and 7.0 μm). The metagenomic analysis of the bacterial bioaerosol sample revealed dominance of Alcaligenaceae (22 %), Stenotrophomonas (19 %), Bacillus (14 %) whereas, Fusarium (40 %), Epicoccum (23 %), Hypocreales (15 %), Coprinopsis (8 %), Cladosporium (4 %), Sarocladium (4 %), Tourlaspora (2 %), Alternaria (2 %) and Cryptococcus (2 %) were dominant fungal species. The top two dominant genera of bacterial strain expressed resistance towards azithromycin and cefixime. In the cross-sectional health survey near the waste processing site, participants including both workers on the site and people nearby, reported symptoms of respiratory, skin and eye irritation and bad smell. This study will help to improve the waste treatment process safety protocols and the health of the population around. © 2025 Elsevier B.V.
Bioaerosol emissions from wastewater treatment process at urban environment and potential health impacts
(Academic Press, 2024) Yogesh Kumar Vishwakarma; Mayank; Kirpa Ram; Mukunda M. Gogoi; Tirthankar Banerjee; R.S. Singh
The inlet of wastewater treatment plants (WWTPs) contains pathogenic microorganisms which during aeration and by mechanical mixing through wind typically aerosolized microbes into ambient air. Bioaerosol emission and its characterization (bacterial and fungal) was investigated considering low-flow and high-flow inlet of wastewater treatment plant. Generation of bioaerosols was found influenced by prevailing seasons while both during summer and winter, fungal concentration (winter: 1406 ± 517; summer: 1743 ± 271 CFU/m3) was higher compared to bacterial concentration (winter: 1077 ± 460; summer: 1415 ± 588 CFU/m3). Bioaerosols produced from WWTPs were predominately in the size range of 2.1–4.7 μm while fraction of fungal bioaerosols were also in ultra-fine range (0.65 μm). Bioaerosols reaching to the air from WWTPs varied seasonally and was calculated by aerosolization ratio. During summer, aerosolization of the bioaerosols was nearly 6 times higher than winter. To constitute potential health effects from the exposure to these bioaerosols, biological characterization, antibiotics resistance and the health survey of the nearby area were also performed. The biological characterization of the bioaerosols samples were done through metagenomic approach using 16s and ITS metagenomic sequencing. Presence of 167 genus of bacteria and 41 genus of fungi has been found. Out of this, bacillus (73%), curtobacterium (21%), pseudomonas, Exiguo bacterium, Acinetobacter bacillaceae, Enterobacteriaceae and Prevotella were the dominant genus (top 10) of bacteria. In case of fungi, xylariales (49%), Hypocreales (19%), Coperinopsis (9%), Alternaria (8%), Fusarium (6%), Biopolaris, Epicoccum, Pleosporaceae, Cladosporium and Nectriaceae were dominant. Antibiotics like, Azithromycin and cefixime were tested on the most dominant bacillus showed resistance on higher concentration of cefixime and lower concentration of azithromycin. Population-based health survey in WWTP nearby areas (50–150 m periphery) found several types of diseases/symptoms including respiratory problem, skin rash/irritation, change in smell and taste, eye irritation within the resident population and workers. © 2024 Elsevier Ltd
Carbon isotope-constrained seasonality of carbonaceous aerosol sources from an urban location (Kanpur) in the Indo-Gangetic Plain
(Wiley-Blackwell, 2017) Srinivas Bikkina; August Andersson; Kirpa Ram; M.M. Sarin; Rebecca J. Sheesley; Elena N. Kirillova; R. Rengarajan; A.K. Sudheer; Örjan Gustafsson
The Indo-Gangetic Plain (IGP) in northern India, Pakistan, and Bangladesh is a major source of carbonaceous aerosols in South Asia. However, poorly constrained seasonality of their sources over the IGP leads to large uncertainty in climate and health effects. Here we present a first data set for year-round radiocarbon (δ14C) and stable carbon (σ13C)-based source apportionment of total carbon (TC) in ambient PM10 (n = 17) collected from an urban site (Kanpur: 26.5°N, 80.3°E) in the IGP during January 2007 to January 2008. The year-round 14C-based fraction biomass (fbio-TC) estimate at Kanpur averages ~77 ± 7% and emphasizes an impact of biomass burning emissions (BBEs). The highest fbio-TC (%) is observed in fall season (October-November, 85 ± 6%) followed by winter (December-February, 80 ± 4%) and spring (March-May, 75 ± 8%), while lowest values are found in summer (June-September, 69 ± 2%). Since biomass/coal combustion and vehicular emissions mostly contribute to carbonaceous aerosols over the IGP, we predict σ13CTC (σ13Cpred) over Kanpur using known σ13C source signatures and the measured δ14C value of each sample. The seasonal variability of σ13Cobs - σ13Cpred versus δ14CTC together with air mass back trajectories and Moderate Resolution Imaging Spectroradiometer fire count data reveal that carbonaceous aerosols in winter/fall are significantly influenced by atmospheric aging (downwind transport of crop residue burning/wood combustion emissions in the northern IGP), while local sources (wheat residue combustion/vehicular emissions) dominate in spring/summer. Given the large temporal and seasonal variability in sources and emission strength of TC over the IGP, 14C-based constraints are, thus, crucial for reducing their uncertainties in carbonaceous aerosol budgets in climate models. © 2017. American Geophysical Union. All Rights Reserved.
Chemical components and distributions of aerosols in the third pole
(Elsevier, 2019) Kirpa Ram; Hemraj Bhattarai; Zhiyuan Cong
The crustal and anthropogenic emission sources play an important role in moderating not only aerosol composition but also have a profound impact on rainwater composition and neutralization processes over the Third Pole (TP). This chapter reports on key findings on spatiotemporal variations in chemical composition of aerosols and rainwater based on ground measurement and satellite retrievals, cryoconites of glaciers and ice-cores over the TP. Carbonaceous species [elemental carbon (EC), organic carbon (OC), and water-soluble organic carbon (WSOC)] are ubiquitously present in the entire TP with pronounced spatial and temporal variability in their concentrations. The western and southern parts of the TP are influenced by the transport of aerosols from the source regions in the Indo-Gangetic plain, Nepal, and neighboring areas. The elevated OC/EC ratios, together with K+ and levoglucosan markers, reflect biomass burning emissions as a major source of primary carbonaceous aerosols. In addition, a significant positive gradient observed in WSOC/OC ratios from the Gangetic plains toward high-altitude sites indicates a contribution from secondary organic aerosols (SOAs). In contrast, the eastern and southeastern TP is mostly influenced by emissions from both China and Southeast Asia. The ground-based measurements, as well as satellite retrievals, unveil a clear seasonal pattern over TP with relatively lower concentrations of chemical species and aerosol optical depth (AOD) during monsoon. In contrast, higher AOD values, along with lower fine-mode aerosol fraction, during spring and summer seasons, are attributed to an increase in the contribution of mineral aerosols from desert regions in the Middle East, and Taklamakan and Gobi, as well as the Thar, deserts. Studies on rainwater composition indicate its alkaline nature and the presence of high concentrations of neutralizing species further ascertaining that crustal aerosols have a profound impact on rainwater composition and neutralization processes over the region. © 2020 Elsevier Inc. All rights reserved.
Chemical composition and source apportionment of total suspended particulate in the central himalayan region
(MDPI, 2021) Rahul Sheoran; Umesh Chandra Dumka; Dimitris G. Kaskaoutis; Georgios Grivas; Kirpa Ram; Jai Prakash; Rakesh K. Hooda; Rakesh K. Tiwari; Nikos Mihalopoulos
The present study analyzes data from total suspended particulate (TSP) samples collected during 3 years (2005–2008) at Nainital, central Himalayas, India and analyzed for carbonaceous aerosols (organic carbon (OC) and elemental carbon (EC)) and inorganic species, focusing on the assessment of primary and secondary organic carbon contributions (POC, SOC, respectively) and on source apportionment by positive matrix factorization (PMF). An average TSP concentration of 69.6 ± 51.8 µg m−3 was found, exhibiting a pre-monsoon (March–May) maximum (92.9 ± 48.5 µg m−3) due to dust transport and forest fires and a monsoon (June–August) minimum due to atmospheric washout, while carbonaceous aerosols and inorganic species expressed a similar seasonality. The mean OC/EC ratio (8.0 ± 3.3) and the good correlations between OC, EC, and nss-K+ suggested that biomass burning (BB) was one of the major contributing factors to aerosols in Nainital. Using the EC tracer method, along with several approaches for the determination of the (OC/EC)pri ratio, the estimated SOC component accounted for ~25% (19.3–29.7%). Furthermore, TSP source apportionment via PMF allowed for a better understanding of the aerosol sources in the Central Himalayan region. The key aerosol sources over Nainital were BB (27%), secondary sulfate (20%), secondary nitrate (9%), mineral dust (34%), and long-range transported mixed marine aerosol (10%). The potential source contribution function (PSCF) and concentration weighted trajectory (CWT) analyses were also used to identify the probable regional source areas of resolved aerosol sources. The main source regions for aerosols in Nainital were the plains in northwest India and Pakistan, polluted cities like Delhi, the Thar Desert, and the Arabian Sea area. The outcomes of the present study are expected to elucidate the atmospheric chemistry, emission source origins, and transport pathways of aerosols over the central Himalayan region. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
Chemical composition, source apportionment of rainwater, and its contribution to nutrient deposition at an urban site of the middle Indo-Gangetic Plain region
(Elsevier B.V., 2025) Sanny Rathore; Kirpa Ram; Pramod Kumar; Arnab Mondal
The study of rainwater chemistry plays an important role in understanding scavenging processes, sources of atmospheric pollutants, and impacts on ecosystems. This study investigated the chemical composition, variations, and potential sources influencing rainwater chemistry in Varanasi, India from 2018 to 2022. A total of 158 event-based monsoonal rainwater samples were analyzed for physical (pH, EC and TDS) and major ionic species (Clˉ, Fˉ, NO3ˉ, SO42−, PO43−, Mg2+, Ca2+, NH4+, Na+ and K+). The average rainwater pH was 6.22 ± 0.45 (n = 158) with ∼92 % of the samples being alkaline with the dominance of Ca2+ and NH4+ ions, whereas the rest of the samples were acidic in nature with high SO42ˉ and NO3ˉ levels. NH4+ concentrations increased significantly until 2020, while those of Ca2+, K+, and Mg2+ initially decreased and rose after 2020. The study highlighted significant deposition of dissolved inorganic nitrogen (in the form of NO3−, NO2−, and NH4+). The average monsoonal nitrogen deposition flux was 8.04 kg ha−1 with significant contributions from NO3− (3.36) and NH4+ (4.67). In contrast, the deposition of inorganic phosphorus was significantly lower (∼0.72 kg ha−1). Thus, the rainwater deposition contributed to overall nutrient deposition, specially N and P which could significantly impact the ecosystem. Neutralization and enrichment factors indicated influences from crustal and anthropogenic sources. This is also evident from the study as ∼99 % of Ca2+ and ∼98 % of SO42− fractions were determined to be of non-marine origin. Over 800 brick kilns were identified around Varanasi and contributing to an increased NO3−, SO42− and particulate matter. The Positive Matrix Factorization (PMF) technique identified sea-salt, crustal dust, fossil fuel and biomass combustion, and agricultural emissions as potential sources of major ionic constituents over Varanasi. © 2025 Turkish National Committee for Air Pollution Research and Control
Climate Change, Disaster and Adaptations: Human Responses to Ecological Changes
(Springer, 2022) Richa Singh; Kirpa Ram; Chandrashekhar Yadav; Azizur Rahman Siddiqui
The impact of climate change is recorded in sea level rise, ocean acidification, coral bleaching, glacier reduction on a shorter time scale as well as an increase of earth’s surface temperature (i.e. global warming) in geological landforms, in ocean sediments and ice cores globally on a longer time scales. Although both natural processes such as change in solar radiation and sunspot activities are most likely to cause climate change, anthropogenic emissions are linked with the recent climate change such as cloud burst and abrupt change in rainfall pattern etc. In the current scenario, the ecosystem is degrading at a faster rate which has led to extreme events like flood, forest fires and drought. In addition, climate change is also linked with other problems such as epidemic, vegetation and habitat losses, some of these can result in a disaster. These disasters can significantly impair the economic growth of the county. Among the entire mammals, only humans have colonised all over the earth. They adapt in such a way that they can survive in extreme climates of geographical poles, arid desert, high altitudes of mountains and remote islands of the Pacific. Most of the time, humans such as sea nomads adapt to the changes occurring in their environment by changing their genetic adaptation to climate change. However, humans sometimes can’t adapt to the changing environment, and they migrate to a suitable place. The observed genetic makeup in modern Indo-Aryans also supports the above hypothesis that climate change caused human migration during and after the collapse of the Indus Valley Civilisation. The literature clearly shows that the main reasons behind the migration are natural disaster, lack of natural resources and poor economic condition. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2022.
Decoupling Natural and Anthropogenic Mercury and Lead Transport from South Asia to the Himalayas
(American Chemical Society, 2020) Jie Huang; Shichang Kang; Runsheng Yin; Mang Lin; Junming Guo; Kirpa Ram; Chaoliu Li; Chhatra Sharma; Lekhendra Tripathee; Shiwei Sun; Feiyue Wang
Mercury (Hg) and lead (Pb) accumulation since the Industrial Revolution has been generally observed to increase concurrently in lake sedimentary records around the world. Located downwind during the monsoon season from the rapidly developing South Asia, the Himalayas and the Tibetan Plateau are expected to receive direct anthropogenic Hg and Pb loadings, yet the source, pathway, and effects of such transport remain poorly known due to logistic challenges in accessing this region. When studying the sediment record from Lake Gokyo (4750 m above sea level (a.s.l.)) in the Himalayas, we find remarkably different Hg and Pb accumulation trends over the past 260 years. Although Hg accumulation has continued to increase since the Industrial Revolution, Pb accumulation peaked during that time and has been decreasing since then. Stable isotope analysis reveals that the decoupling trends between these two elements are due to different sources and pathways of Hg and Pb in the region. Both δ202Hg and Δ199Hg have been increasing since the Industrial Revolution, suggesting that anthropogenic Hg emissions from South Asia have been continuously increasing and that the Indian monsoon-driven wet deposition of atmospheric Hg is the dominant pathway for Hg accumulation in the sediments. In contrast, analysis of 206Pb/207Pb and 208Pb/207Pb ratios suggests that Pb accumulation in the sediments originates primarily from natural sources and that the decreasing trend of Pb accumulation is most likely due to a weakening input of atmospheric mineral dust by the westerlies. These decoupling trends highlight the ongoing issue of transboundary Hg transport to the Himalayas and the Tibetan Plateau that are source waters for major freshwater systems in Asia and calls for regional and international collaborations on Hg emission controls in South Asia. Copyright © 2020 American Chemical Society.
Desert dust as a significant carrier of atmospheric mercury
(Elsevier Ltd, 2020) Jie Huang; Shichang Kang; Runsheng Yin; Kirpa Ram; Xinchun Liu; Hui Lu; Junming Guo; Siyu Chen; Lekhendra Tripathee
The atmospheric circulation plays a critical role in the global transport and deposition of atmospheric pollutants such as mercury (Hg). Desert dust emissions contribute to nearly 60–95% of the global dust budget and thus, desert dust may facilitate atmospheric Hg transport and deposition to the downwind regions worldwide. The role of desert dust in biogeochemical cycling of Hg, however, has not been well recognized by the Hg research community. In this study, we measured the concentration of particulate bound Hg (HgP) in total suspended particulate (TSP) collected from China's largest desert, Taklimakan Desert, between 2013 and 2017. The results show that HgP concentrations over the Taklimakan Desert atmosphere are remarkably higher than those observed from background sites in China and are even comparable to those measured in most of the Chinese metropolitan cities. Moreover, HgP concentrations in the Taklimakan Desert exhibit a distinct seasonal pattern peaking during dust storm outbreak periods in spring and summer (March to August). A preliminary estimation demonstrates that export of total Hg associated with atmospheric dust from the Taklimakan Desert could be 59.7 ± 60.3 (1SD) Mg yr−1. The unexpectedly high HgP concentrations during duststorms, together with consistent seasonal pattern of Hg revealed from the snow/ice, clearly demonstrate that Asian desert dust could act as a significant carrier of atmospheric Hg to the cryosphere of Western China and even can have further global reach. © 2020 Elsevier Ltd