Publications by authors named "Samresh Kumar"

5 Publications

  • Page 1 of 1

Concentrations, transport characteristics, and health risks of PM-bound trace elements over a national park in central India.

J Environ Manage 2021 Sep 4;293:112904. Epub 2021 Jun 4.

Center for Research on Environment and Sustainable Technologies, Indian Indstitute of Science Education and Research Bhopal, India; Earth and Environmental Sciences, Indian Institute of Science Education and Research Bhopal, Bhauri, Bhopal, 462 066, India. Electronic address:

Fine particulate matter (PM) mass and its chemical constituents were measured over Van Vihar National Park (VVNP) in Bhopal, central India. Fine PM collected over two years onto Teflon filters using a Mini-Vol® sampler were analyzed for trace elements using an Energy Dispersive X-ray fluorescence (ED-XRF) spectrometer. The temporal behaviour, dry deposition fluxes and transport pathways of elements, in addition to their health risks were examined in this study. S, K, Si, Al, Ca, and Fe accounted for most of the PM-bound trace elements (~88% on average). Pronounced seasonality was observed for major elements (S, K, and Cl) and reconstructed soil (estimated as the sum of oxides of crustal elements, i.e., Si, Al, Ca, Fe, and Ti), with winter and post-monsoon season highs, potentially due to source strengths and favourable metrology during these seasons. The synoptic meteorology during these seasons favoured the fetch of particles from highly polluted regions such as the Indo-Gangetic Plain. The estimated average dry depositional flux of each element in this study was comparable to those measured/estimated for each of these species over other urban areas. The sum of the dry deposition flux for crustal elements (1301.9 ± 880.7 μg m d) was in agreement with global dust cycle models. Air-parcel trajectory cluster analysis revealed that S, K, and Cl were influenced by biomass and coal burning in predominantly in central, and northwestern India, while reconstructed soil was influenced by air masses from the Arabian and Thar deserts. Finally, human exposure risk assessment to carcinogens (As, Cr, Cd, Pb and Ni) and non-carcinogens (Cu, Zn, Mn, V, Hg, Se and Al) revealed that no significant risk was posed by these elements. The assessment in this study was a screening for severe adverse effects, rather than a speciated health assessment. Thus, over the study region, monitoring, health risk assessment and mitigation measures, where needed, must be enhanced to ensure that trace elements induced health effects continue to be within safe levels.
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September 2021

Source apportionment of fine particulate matter over a National Park in Central India.

Sci Total Environ 2020 Jun 22;720:137511. Epub 2020 Feb 22.

Department of Earth and Environmental Sciences, Indian Institute of Science Education and Research Bhopal Bhopal Bypass Road, Bhauri, Bhopal 462 066, Madhya Pradesh, India; Center for Research on Environment and Sustainable Technologies, Indian Institute of Science Education and Research Bhopal Bhopal Bypass Road, Bhauri, Bhopal 462 066, Madhya Pradesh, India. Electronic address:

PM mass and chemical constituents were measured over Van Vihar National Park (VVNP), a forested location within Bhopal. Positive Matrix Factorization (USEPA PMF5) was applied to two-year long (2012 and 2013) measurements of PM chemical species including water-soluble inorganic ions, organic, pyrolitic, and elemental carbon, and trace elements for the quantitative apportionment of PM mass. The model resolved seven factors. A combination of source profiles, temporal evolution, and potential source locations were used to identify these factors as secondary sulfate, combustion aerosol, re-suspended crustal dust, pyrolysis carbon-rich aerosol, biomass burning aerosol, secondary nitrate, and sea salt with mean contributions of 24.8%, 23.6%, 17.3%, 15.7%, 11%, 4.1%, 0.8%, respectively, to the PM mass during the study period. Rest of the mass was unapportioned. Inter-annual and seasonal variability of sources contributing to PM mass were also assessed. Combustion aerosol and pyrolysis carbon-rich aerosol were responsible for several high PM mass concentration episodes at the sampling location. Re-suspended crustal dust was also found to be contributing to episodic highs in PM mass. Biomass burning aerosol contribution to PM mass increased during stubble burning months in central and northern India. Conditional Bivariate Probability Function (CBPF) and Potential Source Contribution Function (PSCF) analyses were used to identify local and regional source locations (and/or preferred transport pathways) of aerosol sources, respectively. It was found that PM at the study was mostly regionally transported and that the predominant regional source locations were Chhattisgarh, northern and south-eastern parts of Madhya Pradesh, western Uttar Pradesh, Delhi, Haryana, Rajasthan, and the Arabian Sea. The outcomes of this study are expected to strengthen the air quality management plans for both VVNP and the city. Further, it is hoped that the results of this study will provide inputs to validate emissions inventories as well as climate model outputs over the region.
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June 2020

"They don't like us….": Barriers to antiretroviral and opioid substitution therapy among homeless HIV positive people who inject drugs in Delhi: A mixed method study.

PLoS One 2018 30;13(8):e0203262. Epub 2018 Aug 30.

India Health Action Trust (IHAT), Technical Support Unit, Bengaluru, India.

Background: Provision of Anti-Retroviral Therapy (ART) and Opioid Substitution Therapy (OST) are important components of the targeted intervention (TI) programme for people who inject drugs (PWID). Homeless HIV positive PWIDs in Delhi is a key population experiencing gaps in uptake of these services, especially the ART uptake which is reportedly far from 90%, UNAIDS' 90-90-90 target to end the AIDS epidemic.

Objective: To assess the gaps and barriers in accessing the ART and OST services uptake among HIV positive homeless PWID in Delhi and to explore experiences and perspectives of the PWIDs and service providers.

Methodology: We used a convergent parallel mixed methods design which included a cross-sectional quantitative survey and a qualitative study. Two hundred thirty five homeless HIV positive PWID were interviewed and in-depth interviews were conducted with five PWIDs and nine health providers.

Results: While only 12% of PWIDs were on ART, 80% were availing OST services. The top individual, health system related and structural barriers for ART service access were insufficient and incorrect knowledge (63%), long waiting time (86%) and lack of family support (44%) respectively. Inconvenient timings, stringent registration requirements and negative attitude of health providers were expressed as major barriers of accessing ART services during the interviews while these were not a concern in OST services. Homelessness, poverty, stigma were common barriers for both services. Integrated, 'single window' service and provision of additional support like nutrition and shelter were suggested as measures to improve access by both health providers and the PWIDs themselves.

Conclusion: There is an urgent need for structural and health systems changes to improve access to ART and OST services. These include integrated service delivery, flexibility in timing of the centers, accelerated ART initiation, simplification of bureaucratic procedures, nutritional and social support to all homeless HIV positive PWIDs.
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February 2019

PM and PM chemical source profiles with optical attenuation and health risk indicators of paved and unpaved road dust in Bhopal, India.

Environ Pollut 2017 Mar 11;222:477-485. Epub 2017 Jan 11.

Department of Earth and Environmental Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal By-pass Road, Bhauri, Bhopal 462 066, Madhya Pradesh, India.

Size classified (PM and PM) paved and unpaved road dust chemical source profiles, optical attenuation and potential health risk from exposure to these sources are reported in this study. A total of 45 samples from 9 paved road and 6 unpaved road sites located in and around Bhopal were re-suspended in the laboratory, collected onto filter substrates and subjected to a variety of chemical analyses. In general, road dust was enriched (compared to upper continental crustal abundance) in anthropogenic pollutants including Sb, Cu, Zn, Co, and Pb. Organic and elemental carbon (OC/EC) in PM and PM size fractions were 50-75% higher in paved road dust compared to their counterparts in unpaved road dust. Further, the results suggest that when it is not possible to include carbon fractions in source profiles, the inclusion of optical attenuation is likely to enhance the source resolution of receptor models. Additionally, profiles obtained in this study were not very similar to the US EPA SPECIATE composite profiles for PM and PM, for both sources. Specifically, the mass fractions of Si, Fe, OC, and EC were most different between SPECIATE composite profiles and Bhopal composite profiles. An estimate of health indicators for Bhopal road dust revealed that although Cr was only marginally enriched, its inhalation may pose a health risk. The estimates of potential lifetime incremental cancer risk induced by the inhalation of Cr in paved and unpaved road dust (PM and PM) for both adults and children were higher than the baseline values of acceptable risk. These results suggest that road dust Cr induced carcinogenic risk should be further investigated.
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March 2017

First measurements of ambient aerosol over an ecologically sensitive zone in Central India: Relationships between PM2.5 mass, its optical properties, and meteorology.

Sci Total Environ 2016 Apr 2;550:706-716. Epub 2016 Feb 2.

Department of Earth and Environmental Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal 462 066, India.

PM2.5 mass and its optical properties were measured over an ecologically sensitive zone in Central India between January and December, 2012. Meteorological parameters including temperature, relative humidity, wind speed, wind direction, and barometric pressure were also monitored. During the study period, the PM2.5 (fine PM) concentration ranged between 3.2μgm(-3) and 193.9μgm(-3) with a median concentration of 31.4μgm(-3). The attenuation coefficients, βATN at 370nm, 550nm, and 880nm had median values of 104.5Mm(-1), 79.2Mm(-1), and 59.8Mm(-1), respectively. Further, the dry scattering coefficient, βSCAT at 550nm had a median value of 17.1Mm(-1) while the absorption coefficient βABS at 550nm had a median value of 61.2Mm(-1). The relationship between fine PM mass and attenuation coefficients showed pronounced seasonality. Scattering, absorption, and attenuation coefficient at different wavelengths were all well correlated with fine PM mass only during the post-monsoon season (October, November, and December). The highest correlation (r(2)=0.81) was between fine PM mass and βSCAT at 550nm during post-monsoon season. During this season, the mass scattering efficiency (σSCAT) was 1.44m(2)g(-1). Thus, monitoring optical properties all year round, as a surrogate for fine PM mass was found unsuitable for the study location. In order to assess the relationships between fine PM mass and its optical properties and meteorological parameters, multiple linear regression (MLR) models were fitted for each season, with fine PM mass as the dependent variable. Such a model fitted for the post-monsoon season explained over 88% of the variability in fine PM mass. However, the MLR models were able to explain only 31 and 32% of the variability in fine PM during pre-monsoon (March, April, and May) and monsoon (June, July, August, and September) seasons, respectively. During the winter (January and February) season, the MLR model explained 54% of the PM2.5 variability.
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April 2016