Browsing by Author "Prashant Kumar Chauhan"

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A campaign-based study on the physio-chemical characterization and source apportionment of particulate matter in the Central Himalayas
(Springer, 2025) Vikas Rawat; Narendra S. Singh; Surendra K. Dhaka; Prashant Kumar Chauhan; Jagdish Chandra Kuniyal; Prity Singh Pippal; Sanjeev Kimothi; Mayank Kumar Chauhan
This study presents the first campaign-based assessment of the physio-chemical characteristics, sources, and health risks of particulate matter (PM2.5 and PM10) across Uttarakhand state in the Central Himalaya, India. Spanning 13 districts across diverse geographical features during winter and summer with a low volume PM sampler, the research integrates advanced analytical techniques (XRD, SEM–EDX, ICP-MS) with receptor modeling (Positive Matrix Factorization) and health risk assessment. Results reveal significant spatial and seasonal variability: PM2.5 (20–125 µg/m3) and PM10 (25–190 µg/m3) concentrations frequently exceeded WHO guidelines, with higher PM2.5/PM10 ratios (0.48–0.72) in winter indicating anthropogenic dominance, while summer showed stronger crustal influences. Aerosol optical depth (380-1020 nm) was lower at high-altitude sites (0.24–0.46), with spectral anomalies at 936 nm highlighting absorbing aerosols (e.g., black carbon, mineral dust). Mixed aerosols (58%) dominated over dust (18%) and biomass burning (7%). XRD identified carcinogenic quartz and hematite, alongside crustal and industrial minerals (kaolinite, gypsum, calcite etc.). SEM–EDX revealed diverse particle morphologies, with C, O, Si, and Al as dominant elements. PMF source apportionment (ICP-MS) traced PM10 primarily to mineral dust (41.7%) and combustion activities (34.5%), and PM2.5 to biomass burning (12.3%) and dust (51.1%). Enrichment factors and health risk assessments indicated potential non-carcinogenic risks (especially for children) from Cd and Al, and carcinogenic risks from Cr. This study highlights the need for targeted mitigation strategies and future research, incorporating a wider range of PM constituents (ions, carbonaceous aerosols, PAHs, trace gases) for a comprehensive understanding of aerosol impacts in the region. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2025.
Assessment of equivalent black carbon variations and its source apportionment over Varanasi, Indo-Gangetic Basin
(Elsevier B.V., 2024) Prashant Kumar Chauhan; Shani Tiwari; Dileep Kumar Gupta; Akhilesh Kumar; Vineet Pratap; Abhay Kumar Singh
In this study, the temporal variation of Equivalent Black Carbon (eBC) and its source apportionment is studied using a yearlong (Dec. 2020–Nov. 2021) multiwavelength Aethalometer (AE-33 model) measurements over Varanasi, located in the central Indo-Gangetic Basin (IGB). Results suggest that mean mass concentrations of eBC vary in the range between 0.46 ± 0.13 to 11.22 ± 5.09 μg m−3 with an annual mean value of ∼3.57 ± 2.39 μg m−3 during the study period. A strong temporal variation in eBC and its components i.e., eBCff (eBC from fossil fuel), and eBCbb (eBC from biomass burning) are found which shows a large variation on different temporal scales with an average value during winter (6.21 ± 3.56 μg m−3), summer (5.09 ± 3.61 μg m−3), monsoon season (1.52 ± 1.03 μg m−3), and post-monsoon (3.75 ± 2.68 μg m−3). The diurnal variation of eBC shows two different maxima between 07:00–08:00 a.m. and 08:00–10:00 p.m. An inverse relationship between eBC concentration and all meteorological parameters (temperature, wind speed, and boundary layer height) is found except relative humidity. The concentration of eBC increases with respect to RH (up to 70 %) suggesting hygroscopic growth while for higher RH (>70 %) value, eBC concentration decreases and indicates the possible wet scavenging processes in the atmosphere. Source apportionment of eBC using the “Aethalometer Model” reveals that eBCff is dominant over eBCbb in total eBC loading during the study period. Cluster analysis of HYSPLIT (Hybrid Single Particle Lagrangian Integrated Trajectory) model computed five days airmass back-trajectory suggests that airmass reached at Varanasi passes through a highly dense fire count region over the northwestern IGB and surrounding which could be the most responsible for the black carbon loading over the study region. © 2024 Turkish National Committee for Air Pollution Research and Control
Characterization and impact of airborne particulate matter over Varanasi: A year-long study on concentration, morphology, and elemental composition
(Elsevier Ltd, 2024) Prashant Kumar Chauhan; Dileep Kumar Gupta; Abhay Kumar Singh
Air pollution is an important worldwide issue, especially pronounced in metropolitan and suburban regions, significantly affecting both public health and surroundings. This study investigates the particles' morphology and elemental analysis in Varanasi, a highly inhabited metropolis in the Indo-Gangetic Plain. The research was conducted over a year, from April 2019 to March 2020, utilizing Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy, Ion Chromatography, and Atomic Absorption Spectroscopy to analyse particulate matter. Results indicated that mean values of PM2.5 and PM10 were 106.5 ± 67.2μg/m³ and 180.8 ± 71.4 μg/m³, respectively. Often, these amounts exceeded the National Ambient Air Quality Standards. SEM-EDX analysis revealed diverse particle morphologies, with significant contributions from both manmade sources including industrial activities and vehicle emissions, and natural sources, like soil dust. Elemental analysis identified major components, including Carbon, Oxygen, Fluorine, Aluminium, and Silicon. IC analysis highlighted dominant ionic species, such as Ca++, SO4−-, NO3−, and Cl−, with monthly variations reflecting different emission sources. Heavy metals concentrations such as Ni, Cd, Cr, Mn, Cu, Pb, Zn, and Fe were quantified, with concentrations varying significantly across months. The findings underscore the complex nature of aerosols in Varanasi and highlight the immediate need for targeted control over air quality measures to minimize the particulate matter's detrimental effects on the local population and ecosystem. © 2024
Dust storm characteristics over Indo-Gangetic basin through satellite remote sensing
(Elsevier, 2022) Prashant Kumar Chauhan; Akhilesh Kumar; Vineet Pratap; Shivam Kumar Chaubey; Abhay Kumar Singh
The dust storm is a common atmospheric phenomenon that modifies the optical, physical, and radiative properties of aerosols and plays a crucial role in the global radiation budget, and hence global climate change. The present chapter proposes different remote sensing techniques, such as moderate resolution imaging spectroradiometer true-color images, AErosol RObotic NETwork, cloud-aerosol LIDAR, and infrared pathfinder satellite observation (CALIPSO) to study the various properties of dust particles during dust storms over Indo-Gangetic Basin. In addition, Hybrid Single-Particle Lagrangian Integrated Trajectory model is used for the event confirmation and source identification of dust storms. © 2023 Elsevier Ltd. All rights reserved.
Long-term Spatio-temporal Vegetation Dynamics to Climate Change in Koppen Climatic Regions of India
(Springer Science and Business Media Deutschland GmbH, 2024) Ramakant Tiwari; Dileep Kumar Gupta; Prashant Kumar Chauhan; Abhay Kumar Singh
The long-term spatiotemporal vegetation dynamics with climate variables is essential for effectively managing environmental assets. This study presented the long-term spatio-temporal trends of vegetation dynamics and its association with rainfall/temperature in Koppen climate regions from 2000 to 2022. Linear regression (LR) and the Mann-Kendall (MK) test used to analyse the inter-annual and seasonal long-term spatiotemporal trend of vegetation dynamics across the Koppen climate regions during 2000–2022. The parameters (slope, Sen’s slope, Pearson correlation coefficients, Z value, p-value, Kendall Tau, etc.) from the LR and MK test with Sen’s slope are quantifying the significance of vegetation dynamics trends, and their association strengths with climate variables. The statistically significant and strong upward trend of inter-annual NDVI dynamics are found across the Indian region (growth rate of 0.0034/yr) and Koppen climate regions (growth rate ranges for five climate regions is 0.0029/yr–0.0043/yr and for Mountain Climate Region is 0.0011/yr). The statistically significant and strong upward trend found in seasonal NDVI growth for the monsoon, post monsoon, and winter seasons. However, the statistically significant and weak upward trend found in the pre-monsoon season for the Indian region and most of the climate regions. A significant positive association of vegetation dynamics observed with the rainfall across all seasons and climate regions, except the Mountain Climate Region. However, an inverse association of vegetation dynamics observed with temperature across all climate regions, except in a few cases. These findings have significant impacts, influencing decisions in land management, conservation, and strategies for regional climate resilience. © King Abdulaziz University and Springer Nature Switzerland AG 2024.
Seasonal characteristics of PM1, PM2.5, and PM10 over Varanasi during 2019–2020
(Frontiers Media S.A., 2022) Prashant Kumar Chauhan; Akhilesh Kumar; Vineet Pratap; Abhay Kumar Singh
Particulate matter (PM) concentrations and aerosol optical depth (AOD) are measured and correlated simultaneously using a high-volume sampler and a MICROTOPS-II Sunphotometer, respectively. The present work deals with the characteristics of particulate matter (PM1, PM2.5, and PM10) over Varanasi, from April 2019 to March 2020. Daily variation, as well as seasonal variation, reveals the dominancy of fine-mode particles over the Varanasi region in the winter season and the dominancy of coarse-mode particles in the summer season, which was further confirmed by calculating the ratio between particulate matter (PM1/PM10 and PM2.5/PM10). This ratio was discovered to be lowest in the summer and highest in the winter. Annual mean concentrations of PM1, PM2.5, and PM10 are found to be 93.91, 111.34, and 180.70 μgm−3, respectively. The seasonal variation shows relatively a higher concentration of PM1, PM2.5, and PM10 in the winter season, which may be due to stable meteorological conditions and increased biomass burning in winter. Diurnal and seasonal variations in AOD were also studied during this period. A large and small value of AOD represents the dominancy of fine particles over coarse particles. At 500 nm, maximum (1.17) and minimum (0.44) AODs were measured in December and August of 2019, respectively. There was a statistically significant correlation between PM particles (PM1, PM2.5, and PM10) and AOD. Elemental analysis shows that fluorine and carbon are the major elements that were observed in selected samples during the post-monsoon and winter season using SEM-EDX analysis. Copyright © 2022 Chauhan, Kumar, Pratap and Singh.
Short-term exposure to particulate matter (PM10/2.5) from Varanasi, India led to asthma aggravation and early fibrotic changes in mice model: Insights into its regulation
(Elsevier Ltd, 2025) Diksha Sharma; Payal Singh; Prashant Kumar Chauhan; Vandana Soni; Abhay Kumar Singh; Rashmi N. Singh
Background: Particulate matter (PM10/2.5) is a ubiquitous air pollutant with detrimental health impacts where fine particles (PM2.5) are posing serious threats to respiratory health. With potentially worse outcomes, it is silently damaging the lungs of people already suffering from respiratory diseases like asthma. The continuous exposures to poor air quality in recent years raises urgent questions for both, immediate and long-term health impacts. Both PM10/2.5 levels have surpassed the Indian National safety standards raising serious concerns about the environmental and health consequences. Methodology: This study aimed to investigate impact of PM10/2.5 exposures on mice lungs where pathological changes in OVA-induced asthmatic mice lungs were compared with normal mice lungs. BALB/c mice were sensitized with ovalbumin (OVA, i.p), followed by OVA aerosol (1 %OVA) challenge, and later subjected to PM10/2.5 exposures (0.5 mg/kg, i.n) continuously for five consecutive days. Lung samples were assessed for oxidative stress markers (ROS and lipid peroxidation), inflammatory mediators (nitric oxide, histamine, myeloperoxidase, eosinophil peroxidase, IL-6), fibrotic markers (collagen deposition, MMP-9 activity, α-SMA expression), and histopathological changes. Dose-dependent cytotoxicity, oxidative stress induced DNA damage in human alveolar epithelial cells (A549) after PM10/2.5 exposures were thoroughly investigated. Curcumin derived from turmeric (Curcuma longa) is known anti-oxidant and anti-inflammatory molecule, was studied for its therapeutic efficacy on PM-induced asthma aggravations and fibrotic changes. Key findings: Significant lung damage was noted after short-term PM10/2.5 exposures (5 days) with aggravated inflammatory and fibrotic changes in both, normal and asthmatic mice lungs, where PM2.5 exposure was severe. Significant morphological and histopathological changes like lung tissue remodeling, epithelial thickening, and collagen deposition was observed. Enhanced immune cell recruitment, ROS and MDA levels along with significantly decreased key antioxidant enzymes, Superoxide dismutase (SOD) and Catalase, compared to the control group were noted with reduced GSH level. Upregulated expression of NF-kB, a transcription factor after PM10/2.5 exposure was found in normal mice which was heightened in asthmatic mice. Enhanced MMP-9 activity was also confirmed by immunofluorescent detection of Alpha-smooth muscle actin (α-SMA). Curcumin, a plant-derived molecule, significantly mitigated PM2.5 exposed airway inflammation and fibrotic changes in lungs by suppressing NF-κB expression and enhancing Nrf2 level. In vitro studies validated these findings, where dose-dependent decrease in cell viability and increased in ROS level along with apoptotic changes A549 cells were observed after PM exposure. Enhanced IL-6 and PARP-1 expression confirmed progressive PM2.5 exposure induced cytotoxicity in A549 cells which was reduced after curcumin treatment. Significance: These findings draw the attention towards detrimental impacts of poor air quality of Varanasi city with genotoxic effects which have not been reported before. Therapeutic potential of Curcumin as a natural protective agent against PM-induced respiratory damage revealed antioxidant-based interventions. It may be alarming for residents living in such polluted environments, particularly susceptible asthmatic population where silent pathological changes are in progress, thus, more detailed investigations are required along with improved air quality management policies in polluted urban areas in near future. © 2025 Elsevier Ltd
Variation of aerosol optical and physical properties and their impact on rainfall over Indo-Gangetic Basin
(Springer, 2025) Akhilesh Kumar; Sadanand N. Singh; Prashant Kumar Chauhan; Gyaneshwar R. Sharma; Vineet Pratap; Anil Kumar Singh
Aerosols are one of the important constituents of the atmosphere which can disturb the Indian monsoon by affecting the precipitation over Indian subcontinents. To investigate the consequence of aerosol properties on rainfall, we have analysed the long-term annual trends and annual correlation between aerosol properties and rainfall using ground-based AErosol RObotic NETwork (AERONET) data and satellite-based Moderate Resolution Imaging Spectroradiometer (MODIS) data. We have used four diverse sites in Indo- Gangetic Basin (IGB); Gandhi College, Jaipur, Lahore, and Kanpur. A significant trend of aerosol optical depth (AOD) and angstrom exponent (AE) along with the trend of imaginary refractive index (IRI)/ real refractive index (RRI) followed by the trend of single scattering albedo (SSA) over Gandhi College, Jaipur and Lahore suggests enhancement of coarse mode scattering and absorbing aerosols. In contrast, over Lahore, a significant reduction in fine mode absorbing aerosols is found. The trend of Aerosol Radiative Forcing (ARF) is found to be decreasing over Gandhi College, Lahore, and Kanpur while it is found to be increasing over Jaipur. A significantly increasing trend of rainfall over Lahore and Kanpur while a considerably decreasing trend over Gandhi College and Jaipur is, found. AOD shows a positive correlation over all locations and AE also indicates a positive correlation over three locations instead of Jaipur. SSA exhibits a negative correlation with rainfall over Jaipur, Kanpur, and Gandhi College while it is found to have a positive correlation over Lahore. RRI shows a negative trend overall locations except Kanpur. In contrast, IRI shows a negative trend with rainfall over all of Lahore and Kanpur and a positive trend over Jaipur and Gandhi College. And, ARF displays a constructive correlation with rainfall over all the locations. © The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature 2025.