Publications by authors named "Ramya Sunder Raman"

15 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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http://dx.doi.org/10.1016/j.jenvman.2021.112904DOI Listing
September 2021

Size-segregated chemical source profiles and potential health impacts of multiple sources of fugitive dust in and around Bhopal, central India.

Environ Pollut 2021 Sep 19;284:117385. Epub 2021 May 19.

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

PM and PM fugitive dust samples from multiple sources (construction, demolition, industrial, agricultural fields, and bare ground) were collected in triplicate for each size bin, from 18 distinct locations in and around Bhopal, central India. The dust samples were dried, sieved, and re-suspended in a chamber fitted with a suitable sampling system, to collect PM and PM samples onto Teflon and Quartz filters. The filters were subjected to gravimetric and chemical analyses. Trace elements, water-soluble ions, and thermal-optical carbon fractions were quantified using a variety of analyses. These species were then used to develop PM and PM chemical source profiles of the fugitive dust sources. As expected, crustal species were abundant in all source categories. For industrial dust, Fe contribution to mass in both size fractions was about 11.4% and above the upper continental crustal abundance. Further, the source profiles generated for each source were different from their counterparts in the US EPA SPECIATE database and profiles reported in literature. Thus, it will be useful to utilize profiles generated in this study to enhance receptor model performance for the study region. However, collinearity analysis of the profiles revealed that PM agricultural and bare ground dust; and PM construction and demolition dust profile pairs may not be separated by receptor models. Finally, a human health risk assessment revealed that construction and industrial dust may pose significant risk to the population. The Incremental Lifetime Cancer Risk (ILCR) metric revealed that adults (2 × 10) and children (1 × 10) were susceptible to cancer risk from exposure to metals in PM fugitive dust. Further, children were more vulnerable than adults. This finding merits further investigation of oxidation state and solubility/bioavailability of Cr and Ni in fugitive dusts.
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http://dx.doi.org/10.1016/j.envpol.2021.117385DOI Listing
September 2021

Population exposure across central India to PM derived using remotely sensed products in a three-stage statistical model.

Sci Rep 2021 01 12;11(1):544. Epub 2021 Jan 12.

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

Surface PM concentrations are required for exposure assessment studies. Remotely sensed Aerosol Optical Depth (AOD) has been used to derive PM where ground data is unavailable. However, two key challenges in estimating surface PM from AOD using statistical models are (i) Satellite data gaps, and (ii) spatio-temporal variability in AOD-PM relationships. In this study, we estimated spatially continuous (0.03° × 0.03°) daily surface PM concentrations using MAIAC AOD over Madhya Pradesh (MP), central India for 2018 and 2019, and validated our results against surface measurements. Daily MAIAC AOD gaps were filled using MERRA-2 AOD. Imputed AOD together with MERRA-2 meteorology and land use information were then used to develop a linear mixed effect (LME) model. Finally, a geographically weighted regression was developed using the LME output to capture spatial variability in AOD-PM relationship. Final Cross-Validation (CV) correlation coefficient, r, between modelled and observed PM varied from 0.359 to 0.689 while the Root Mean Squared Error (RMSE) varied from 15.83 to 35.85 µg m, over the entire study region during the study period. Strong seasonality was observed with winter seasons (2018 and 2019) PM concentration (mean value 82.54 µg m) being the highest and monsoon seasons being the lowest (mean value of 32.10 µg m). Our results show that MP had a mean PM concentration of 58.19 µg m and 56.32 µg m for 2018 and 2019, respectively, which likely caused total premature deaths of 0.106 million (0.086, 0.128) at the 95% confidence interval including 0.056 million (0.045, 0.067) deaths due to Ischemic Heart Disease (IHD), 0.037 million (0.031, 0.045) due to strokes, 0.012 million (0.009, 0.014) due to Chronic Obstructive Pulmonary Disease (COPD), and 1.2 thousand (1.0, 1.5) due to lung cancer (LNC) during this period.
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http://dx.doi.org/10.1038/s41598-020-79229-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7804491PMC
January 2021

Correction to: Chemical characterization of PM aerosol in Delhi and source apportionment using positive matrix factorization.

Environ Sci Pollut Res Int 2020 Nov;27(33):42192

Department of Civil Engineering, Indian Institute of Technology Kanpur, Kanpur, India.

The correct 1st Author name is Jai Prakash.
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http://dx.doi.org/10.1007/s11356-020-10447-2DOI Listing
November 2020

Weight-of-evidence approach to identify regionally representative sites for air-quality monitoring network: Satellite data-based analysis.

MethodsX 2020 4;7:100949. Epub 2020 Jun 4.

Center for Atmospheric Science, IIT Delhi, Delhi - 110016, Delhi, India.

The methodology discussed in Lekinwala et al., 2020, hereinafter referred to as the 'parent article', is used to setup a nation-wide network for background PM measurement at strategic locations, optimally placing sites to obtain maximum regionally representative PM concentrations with minimum number of sites. Traditionally, in-situ PM measurements are obtained for several potential sites and compared to identify the most regionally representative sites [4], Wongphatarakul et al., 1998) at the location. The 'parent article' proposes the use of satellite-derived proxy for aerosol (Aerosol Optical Depth, AOD) data in the absence of in-situ PM2.5 measurements. This article focuses on the details about satellite-data processing which forms part of the methodology discussed in the 'parent article'. Following are some relevant aspects:•High resolution AOD is retrieved from Moderate Resolution Imaging Spectroradiometer (MODIS) instruments aboard NASA's Aqua and Terra satellite using Multi-Angle Implementation of Atmospheric Correction (MAIAC) algorithm. The data is stored as grids of size 1200  ×  1200 and a total of seven such grids cover the Indian land mass. These grids were merged, regridded and multiplied by conversion factors from GEOS-Chem Chemical Transport Model to obtain PM values. Standard set of tools like CDO and NCL are used to manipulate the satellite-data (*.nc files).•The PM values are subjected to various statistical analysis using metrics like coefficient of divergence (CoD), Pearson correlation coefficient (PCC) and mutual information (MI).•Computations for CoD, MI are performed using Python codes developed in-house while a function in NumPy module of Python was used for PCC calculations.
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http://dx.doi.org/10.1016/j.mex.2020.100949DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7317679PMC
June 2020

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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http://dx.doi.org/10.1016/j.scitotenv.2020.137511DOI Listing
June 2020

A note on unusual Si/Al ratios in PM and PM road dust at several locations in India.

Chemosphere 2017 Aug 19;181:376-381. Epub 2017 Apr 19.

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:

The Si/Al ratios in road dust (PM and/or PM) at several locations in India were examined and found to range between 1.6 and 84.9. The potential factors for this wide range of unusual Si/Al ratios in road dust are not known at this time. In addition to re-assessing data quality, the observations suggest the need to carefully quantify anthropogenic inputs of these elements to road dust. The findings of this study also contradict popular assumptions about minimal enrichment of crustal elements by anthropogenic sources and highlight the need to re-visit dust mass estimation using Si and Al as a surrogate. Further, characterization of Si/Al ratio in road dust at locations in India and the influence of local geology/geochemistry on it are especially important, if this ratio is to be used either for dust estimation or as an input to ambient aerosol mass source apportionment models.
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http://dx.doi.org/10.1016/j.chemosphere.2017.04.077DOI Listing
August 2017

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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http://dx.doi.org/10.1016/j.envpol.2016.11.067DOI Listing
March 2017

Chemical characterization of PM aerosol in Delhi and source apportionment using positive matrix factorization.

Environ Sci Pollut Res Int 2017 Jan 10;24(1):445-462. Epub 2016 Oct 10.

Department of Civil Engineering, Indian Institute of Technology Kanpur, Kanpur, India.

Fine aerosol fraction (particulate matter with aerodynamic diameter <= 1.0 μm (PM)) over the Indian Institute of Technology Delhi campus was monitored day and night (10 h each) at 30 m height from November 2009 to March 2010. The samples were analyzed for 5 ions (NH, NO, SO, F, and Cl) and 12 trace elements (Na, K, Mg, Ca, Pb, Zn, Fe, Mn, Cu, Cd, Cr, and Ni). Importantly, secondary aerosol (sulfate and nitrate) formation was observed during dense foggy events, supporting the fog-smog-fog cycle. A total of 76 samples were used for source apportionment of PM mass. Six factors were resolved by PMF analyses and were identified as secondary aerosol, secondary chloride, biomass burning, soil dust, iron-rich source, and vehicular emission. The geographical location of the sources and/or preferred transport pathways was identified by conditional probability function (for local sources) and potential source contribution function (for regional sources) analyses. Medium- and small-scale metal processing (e.g. steel sheet rolling) industries in Haryana and National Capital Region (NCR) Delhi, coke and petroleum refining in Punjab, and thermal power plants in Pakistan, Punjab, and NCR Delhi were likely contributors to secondary sulfate, nitrate, and secondary chloride at the receptor site. The agricultural residue burning after harvesting season (Sept-Dec and Feb-Apr) in Punjab, and Haryana contributed to potassium at receptor site during November-December and March 2010. The soil dust from North and East Pakistan, and Rajasthan, North-East Punjab, and Haryana along with the local dust contributed to soil dust at the receptor site, during February and March 2010. A combination of temporal behavior and air parcel trajectory ensemble analyses indicated that the iron-rich source was most likely a local source attributed to emissions from metal processing facilities. Further, as expected, the vehicular emissions source did not show any seasonality and was local in origin.
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http://dx.doi.org/10.1007/s11356-016-7708-8DOI Listing
January 2017

Novel structurally tuned DAMN receptor for "in situ" diagnosis of bicarbonate in environmental waters.

Analyst 2016 Apr 17;141(8):2367-70. Epub 2016 Mar 17.

Department of Centre for Research on Environmental and Sustainable Technologies, Indian Institute of Science Education and Research Bhopal, Bhouri, Indore-bypass, Bhopal, India-462066.

A new diaminomalenonitrile (DAMN) based charge transfer (CT) chromophore has been designed and synthesized. The receptor demonstrates highly specific and prompt bicarbonate anion (HCO3(-)) sensing in aqueous solution. Interaction with HCO3(-) triggers facile CT across the system, and enables the in situ recognition of water soluble carbonates. The recognition allows us to obtain qualitative as well as quantitative information from aqueous media. The inimitable potential of the receptor was further utilized for monitoring bicarbonate in a range of environmental waters.
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http://dx.doi.org/10.1039/c6an00218hDOI Listing
April 2016

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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http://dx.doi.org/10.1016/j.scitotenv.2016.01.092DOI Listing
April 2016

Airborne black carbon concentrations over an urban region in western India-temporal variability, effects of meteorology, and source regions.

Environ Sci Pollut Res Int 2013 Mar 10;20(3):1617-31. Epub 2012 Jul 10.

Department of Physics, Indian Institute of Science Education and Research (IISER) Bhopal, Govindpura, Bhopal, 462 023, India.

This study characterizes over 5 years of high time resolution (5 min), airborne black carbon (BC) concentrations (July 2003 to December 2008) measured over Ahmedabad, an urban region in western India. The data were used to obtain different time averages of BC concentrations, and these averages were then used to assess the diurnal, seasonal, and annual variability of BC over the study region. Assessment of diurnal variations revealed a strong association between BC concentrations and vehicular traffic. Peaks in BC concentration were co-incident with the morning (0730 to 0830, LST) and late evening (1930 to 2030, LST) rush hour traffic. Additionally, diurnal variability in BC concentrations during major festivals (Diwali and Dushera during the months of October/November) revealed an increase in BC concentrations due to fireworks displays. Maximum half hourly BC concentrations during the festival days were as high as 79.8 μg m(-3). However, the high concentrations rapidly decayed suggesting that local meteorology during the festive season was favorable for aerosol dispersion. A multiple linear regression (MLR) model with BC as the dependent variable and meteorological parameters as independent variables was fitted. The variability in temperature, humidity, wind speed, and wind direction accounted for about 49% of the variability in measured BC concentrations. Conditional probability function (CPF) analysis was used to identify the geographical location of local source regions contributing to the effective BC measured (at 880 nm) at the receptor site. The east north-east (ENE) direction to the receptor was identified as a major source region. National highway (NH8) and two coal-fired thermal power stations (at Gandhinagar and Sabarmati) were located in the identified direction, suggesting that local traffic and power plant emissions were likely contributors to the measured BC.
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http://dx.doi.org/10.1007/s11356-012-1053-3DOI Listing
March 2013

Source apportionment of the ionic components in precipitation over an urban region in Western India.

Environ Sci Pollut Res Int 2011 Feb 7;18(2):212-25. Epub 2010 Jul 7.

Space and Atmospheric Sciences Division, Physical Research Laboratory, Navrangpura, Ahmedabad, 380 009, India.

Introduction: Inorganic ion concentrations in event-based wet-only precipitation samples collected during the south-west (SW) monsoon at an urban location in Western India, Ahmedabad between July 2000 and September 2002 were measured by Rastogi and Sarin (2007).

Methods: For the first time at a location in India, an advanced factor analysis model was retrospectively applied to the measured concentrations of ions (Rastogi and Sarin 2007) in precipitation for source apportionment. Positive matrix factorization resolved five factors, including crustal material, sea salt, nitrate/sulfate-rich factor, ammonium-rich factor, and free acidity.

Results And Discussion: Amongst the model-resolved factors, crustal material was the highest contributor to the total dissolved solids (TDS) accounting for 44.1% on average. Potential source contribution function (PSCF) analysis identified source locations along the eastern coast of Somalia, Yemen, Oman, and the United Arab Emirates for this factor. Sea salt was the second highest contributor accounting for 29.8%. The potential source regions of this factor were also identified in the Arabian Sea and the southern Indian Ocean along the coast of Africa, and the Arabian Gulf. This study also examined the spatial relationships between the source locations of chemical species in precipitation and in ambient aerosol (resolved in an earlier study).

Conclusions: Crustal material was the highest contributor to TDS at the study location. Spatial relationships between aerosol and precipitation factor source regions suggested that below-cloud scavenging of aerosol particles was a likely contributor to the chemical species apportioned to various precipitation factors. Additionally, source types of chemical species in precipitation resolved in this study were qualitatively compared with those identified at other locations in India. The comparison showed that soil was an important contributor to the dissolved mass of chemical species in precipitation at all locations in India.
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http://dx.doi.org/10.1007/s11356-010-0365-4DOI Listing
February 2011

Source identification of ambient aerosols over an urban region in western India.

J Environ Monit 2010 Jun 9;12(6):1330-40. Epub 2010 Apr 9.

Space and Atmospheric Sciences Division, Physical Research Laboratory, Navrangpura, Ahmedabad, 380 009, India.

A first-of-its-kind source apportionment study of the Ahmedabad, India aerosol was conducted in order to determine the major sources contributing to the measured total suspended particles (TSPs). TSP samples were collected approximately once every ten days between May 2000 and January 2003, and analyzed for TSP mass, anions, cations, and elemental concentrations. An advanced factor analysis technique, positive matrix factorization (PMF) was applied to the measured concentrations and six factors were resolved. The model resolved factors included airborne regional dust, calcium carbonate rich dust, biomass burning/vehicular emissions, secondary nitrate/sulfate, marine aerosol, and smelter. Among the resolved factors, airborne regional dust was the highest contributor to the measured TSP mass followed by calcium carbonate rich dust with their average contributions accounting for 57.9 and 19.0%, respectively. Thus, crustal factors were the most dominant sources of TSP in Ahmedabad accounting for nearly 77% of the mass. Potential source contribution function (PSCF) analysis identified parts of Madhya Pradesh and Uttar Pradesh, regions in southwestern Pakistan along the Indo-Gangetic Plain (IGP), and southern Iran as potential source locations for the airborne regional dust factor. In contrast, Rajasthan and Madhya Pradesh, and parts of northern Pakistan were identified as potential source locations for the calcium carbonate rich dust factor. It is hypothesized that aerosol contributions from several limestone quarries in Rajasthan and Madhya Pradesh may have resulted in this factor being calcium carbonate enriched.
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http://dx.doi.org/10.1039/b925511gDOI Listing
June 2010

Characterization of fine aerosol and its inorganic components at two rural locations in New York State.

Environ Monit Assess 2008 Sep 10;144(1-3):351-66. Epub 2007 Nov 10.

Department of Chemical and Biomolecular Engineering, Clarkson University, Potsdam, NY 13699-5708, USA.

Samples of PM(2.5) were collected to measure the concentrations of its chemical constituents at two rural locations, Potsdam and Stockton, NY from November 2002 to August 2005. These samples were collected on multiple filters at both sites, every third day for a 24-h interval with a speciation network sampler. The Teflo filters were analyzed for PM(2.5) mass by gravimetry, and elemental composition by X-ray fluorescence (XRF). Nylasorb filters and Teflo filters were leached with water and analyzed for anions and cations, respectively, by ion chromatography (IC). Fine particulate matter (PM(2.5)) mass and its inorganic component measurements were statistically characterized, and the temporal behavior of these species were assessed. Over the entire study period, PM(2.5) mass concentrations were lower at Potsdam (8.35 microg/m(3)) than at Stockton (10.24 microg/m(3)). At both locations, organic matter (OM) was the highest contributor to mass. Sulfate was the second highest contributor to mass at 27.0% at Potsdam, and 28.7% at Stockton. Nitrate contributions to mass of 8.9 and 9.5% at Potsdam and Stockton, respectively, were the third highest. At both locations, fine PM mass exhibited an annual cycle with a pronounced summer peak and indications of another peak during the winter, consistent with an overall increase in the rate of secondary aerosol formation during the summer, and increased partitioning of ammonium nitrate to the particle phase and condensation of other semi-volatiles during the winter, respectively. An ion-balance analysis indicated that at both locations, during the summers as well as in the winters, the aerosol was acidic. Lognormal frequency distribution fits to the measured mass concentrations on a seasonal basis indicated the overall increase in particle phase secondary aerosol (sulfate and SOA) concentrations during the summers compared to the winters at both locations.
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http://dx.doi.org/10.1007/s10661-007-9998-2DOI Listing
September 2008
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