A. Vinod Kumar

Source apportionment of suspended particulate matter at two traffic junctions in Mumbai, India

Abstract Very high concentration of suspended particulate matter (SPM) is observed at traffic junctions in India. Factor analysis-multiple regression (FA-MR), a receptor modelling technique has been used for quantitative apportionment of the sources contributing to the SPM at two traffic junctions (Sakinaka and Gandhinagar) in Mumbai, India. Varimax rotated factor analysis identified (qualitative) five possible sources; road dust, vehicular emissions, marine aerosols, metal industries and coal combustion. A quantitative estimation by FA-MR model indicated that road dust contributed to 41%, vehicular emissions to 15%, marine aerosols to 15%, metal industries to 6% and coal combustion to 6% of the SPM observed at Sakinaka traffic junction. The corresponding figures for Gandhinagar traffic junction are 33%, 18%, 15%, 8% and 11%, respectively. Due to limitation in source marker elements analysed about 16% of the remaining SPM at these two traffic junctions could not be apportioned to any possible sources by this technique. Of the observed lead in the SPM, FA-MR apportioned 62% to vehicular emissions, 17% to road dust, 11% to metal industries, 7% to coal combustion and 3% to marine aerosols at Gandhinagar traffic junction and about a similar apportionment for lead in SPM at Sakinaka traffic junction.

A comprehensive Eulerian modeling framework for airborne mercury species: Development and testing of the Tropospheric Chemistry module (TCM)

Abstract A comprehensive mercury model system using the Eulerian reference frame of the Acid Deposition and Oxidant Model (ADOM) is being developed to study the regional transport of atmospheric mercury species. A stand-alone version of the ADOM cloud mixing, scavenging, chemistry and wet deposition model components referred to as the Tropospheric Chemistry Module (TCM) is used to investigate the sensitivity of various chemical and meteorological parameters, assumed to be important for mercury deposition phenomena. The TCM chemistry scheme was developed by systematic simplification of the detailed Chemistry of Atmospheric Mercury (CAM) process model, which is based on the current knowledge of physico-chemical forms and transformation reactions of atmospheric mercury species. The first part of the paper describes the general approach to the TCM formulation. The second part presents sensitivity studies of the TCM behavior under different environmental conditions and a comparison of TCM results with observed concentrations of total mercury concentrations in precipitation (Hg(tot)). The results indicate that the TCM has capabilities to examine the relative importance and sensitivity of numerous mercury processes in the troposphere and to reproduce observed Hg(tot) concentrations reasonably well justifying its ultimate use in the full ADOM model.

A comprehensive Eulerian modelling framework for airborne mercury species: model development and applications in Europe

Abstract A comprehensive mercury model system using the Eulerian reference frame of the Acid Deposition and Oxidant Model (ADOM) has been developed under the Canada–Germany Science & Technology Co-operation Agreement and applied within the European Union MArine Science and Technology–BAltic Sea SYstem Study (MAST-III-BASYS) and the Environment & Climate project Mercury Species over Europe (MOE), to study the regional transport and deposition fluxes of atmospheric mercury species. The model is able to simulate long-range transport of mercury over the entire depth of the troposphere with a basic time step of 1 h and incorporates current knowledge of physico-chemical forms and transformation reactions of atmospheric mercury species. Model predicted concentration and deposition pattern of mercury species over Europe are presented and concentrations of total gaseous mercury in ambient air and total mercury in precipitation calculated by the model are compared with observed values from a BASYS monitoring network study in February/March 1998. Concentrations in air agree within a factor of about 2 with observed values, thus indicating that the model is capable of reproducing observations satisfactorily even on an hourly basis. Observed monthly average concentrations in precipitation at four monitoring stations at the Baltic Sea coast are reproduced by the model within a factor of 1.3 suggesting that the chemical scheme in the model is based on an adequate parameterisation of aqueous phase chemistry.

Daily intake of trace metals through coffee consumption in India

The trace element contents of five varieties of instant coffee powder available in the Indian market have been analysed. Ca, Cr, Fe, K, Mg, Mn, Ni, Sr, Zn and Pb, Cd, Cu have been determined using atomic absorption spectrophotometry and differential pulse anodic stripping voltammetry, respectively. The metal levels in the coffee powders observed in this study are comparable with those reported for green coffee beans (Arabica and Robusta variety) reported worldwide with the exception of Sr and Zn, which were on the lower side of the reported values. Concentrations of these metals have been converted into intake figures based on coffee consumption. The daily intakes of the above metals through ingestion of coffee are 1.4mg, 1.58 µg, 124 µg, 41.5mg, 4.9mg, 17.9 µg, 2.9 µg, 3.8 µg, 12.5 µg, 0.2 µg, 0.03 µg and 15.5 µg, respectively. The values, which were compared with the total dietary intake of metals through ingestion by the Mumbai population, indicate that the contribution from coffee is less than or around 1% for most of the elements except for Cr and Ni which are around 3%.

Daily intake of aluminium by adult population of Mumbai, India

Electrothermal atomic absorption spectrophotometry (ET-AAS) has been used for the determination of Al in environmental and food samples with a detection limit of 0.3 ng ml(-1). The reliability of estimation is assessed through the analysis of Standard Reference Materials (IAEA SRMs) of Soil-7, SL-3, SD-M2/TM and Hay (V-10). The results indicate that the average concentration of aluminium in air particulate samples is 5.3 microg m(-3). The daily intake of Al by the adult population of Mumbai is 6.4 mg day(-1).

Application of a numerical model for the planetary boundary layer to the vertical distribution of radon and its daughter products

Abstract A one-dimensional numerical planetary boundary layer (PBL) model is developed and applied to study the vertical distribution of radon and its daughter products in the atmosphere. The meteorological model contains parameterization for the vertical diffusion coefficient based on turbulent kinetic energy and energy dissipation (E–e model). The increased vertical resolution and the realistic concentration of radon and its daughter products based on the time-dependent PBL model is compared with the steady-state model results and field observations. The ratio of radon concentration at higher levels to that at the surface has been studied to see the effects of atmospheric stability. The significant change in the vertical profile of concentration due to decoupling of the upper portion of the boundary layer from the shallow lower stable layer is explained by the PBL model. The disequilibrium ratio of 214 Bi / 214 Pb broadly agrees with the observed field values. The sharp decrease in the ratio during transition from unstable to stable atmospheric condition is also reproduced by the model.

Atmospheric and children's blood lead as indicators of vehicular traffic and other emission sources in Mumbai, India.

Average concentration of Pb in atmospheric air particulates in different suburbs of Mumbai was studied for almost a decade and its spatial and temporal profiles are discussed in relation to emission sources. In general the concentration of Pb in all the residential suburban atmosphere is well below the Central Pollution Control Board (CPCB, 1994) prescribed limit of 1.5 microg m(-3) barring a few exceptions for some residential/industrial sites, such as those of Thane and Kurla scrap yards. The correlation between blood lead of children and air lead reveals that the blood Pb level in children could increase by 3.6 microg dl(-1) for an incremental rise of 1.0 microg Pb m(-3) of air. The temporal profile of air Pb values indicates a decreasing trend in residential suburbs (Khar: 1984, 0.39 microg m(-3); 1996, 0.17 microg m(-3)) as well as in suburban residential areas with low traffic (Goregaon: 1984, 0.53 microg m(-3); 1996, 0.30 microg m(-3)).

Monitoring and modelling of indoor radon concentrations in a multi-storey building at Mumbai, India.

Radon (Rn(222)) levels in an indoor atmosphere of a multi-storey building at Mumbai have been measured for one year covering all the four seasons. Monitoring was carried out using the time-integrated passive detector technique, using Kodak-115 type Solid State Nuclear Track Detector (SSNTD) films of 2.5x2.5 cm size. Measured indoor radon levels showed a decreasing trend with height with concentration ranging from 41 Bq m(-3) at ground floor level to 15 Bq m(-3) at 19th floor level. Using the dose conversion factors, the inhalation dose due to breathing of radon gas is estimated to be 1.03 mSv y(-1) at the ground floor to 0.38 mSv y(-1) at the 19th floor level. Measured indoor radon concentrations on each floor were compared with the computed values using a mathematical model. The agreement between measured values and calculated values of indoor concentrations at different floors was very good within the limitations of various field parameter values.

Intake of Chromium by the Adult Population of Mumbai City

Electro Thermal Atomic Absorption Spectrophotometry (ET-AAS), is used for the determination of chromium (Cr) in a variety of environmental matrices. The detection limit for the estimation of Cr is 2 pg absolute for a volume injection of 20 μl. The precision of the method is established by analysing Cr from a synthetic mixture containing various elements in different qualities (0.5–10 ppm) and is found to be within ± 8%. The reliability of estimation is further assessed through the analysis of Standard Reference Materials (SRMs) of soil, hay, milk powder and lake sediment obtained from IAEA.The total intake of Cr through air, water and food works out to be 54 μg/day for the adult population of Mumbai city. The dietary intake through food is the major contributor to the total intake of Cr. The concentration of Cr in atmospheric air and drinking water collected from different suburbs showed geometric mean concentrations of 0.09 μg/m3 and 0.3 μg/l, respectively. The daily intake of Cr, though lower, is closer to the lower bound of the recommended value of 50–200 μg/day.

Concentrations of uranium in drinking water and cumulative, age-dependent radiation doses in four districts of Uttar Pradesh, India

The present work deals with the determination of uranium concentrations in drinking and ground water samples by laser fluorimetry and calculation of cumulative, age-dependent radiation doses to humans. The concentrations were found to be between 0.20 ± 0.03 and 64.0 ± 3.6 μg L−1, with an average of 11.1 ± 1.5 μg L−1, well within the drinking water limit of regulatory bodies. The concentrations of uranium increase with depth of water samples collection. The estimated annual ingestion dose due to the intake of uranium through drinking water for all age groups varied between 0.2 and 137 μSv a−1, with an average of 17.3 μSv a−1. The mean annual ingestion dose is 5% of the global average ingestion dose, for infants, marginally higher than for other age group. Most effective dose values were less than 20 μSv a−1.