Subhan Khan

Subhan Khan

PhD (Radiation Physics)

About

41
Publications
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Publications

Publications (41)
Article
Full-text available
In the present study, we present results of radiometric and petrographic analyses of sediment samples collected from the river banks of Jhelum, Neelum, and Kunhar confluencing in the district Muzaffarabad. Gamma activity concentrations due to ²²⁶Ra, ²³²Th, and ⁴⁰K were determined using high-purity germanium detector (HPGe). For a total of thirty se...
Conference Paper
Radon progeny measurements can improve dose estimates based on radon gas measurements alone. The airborne activity-size distribution ratio affects the available dose rate per unit radon. Measurements of surface deposited alpha activity and radon concentration can be used in a semi-empirical model to estimate the equilibrium ratio, the free fraction...
Article
With observations of black carbon (BC) aerosol concentrations, optical and radiative properties were obtained over the urban city of Karachi during the period of March 2006–December 2008. BC concentrations were continuously measured using an Aethalometer, while optical and radiative properties were estimated through the Optical Properties of Aeroso...
Article
Black Carbon (BC) mass concentration was measured continuously for every five-minute interval with ground-based Aethalometer at an urban site in Karachi for the period from 2006 to 2008. In this study, the temporal (diurnal, monthly and seasonal) variations of BC and its relationship with meteorological variables were analyzed. Monthly averaged con...
Article
Full-text available
This paper uses Normalized Difference Water Index (NDWI) of McFeeters (1996), Water Index (WI) introduced by Rogers and Kearney (2004), referred to as Red and Short Wave Infra-Red (RSWIR) and WI suggested as the best by Ji et al. (2009), referred to as Green and Short Wave Infra-Red (GSWIR) for delineating and mapping of surface water using MODIS (...
Article
Full-text available
The present study describes the characterization of carbonaceous species including elemental carbon (EC), organic carbon (OC), total carbon (TC), crustal (Al, Ca, Mg, Fe, S, and Ti) and trace metals (As, Ba, Cd, Cr, Cu, Mn, Ni, Pb, Sn and Zn) in PM 10 samples collected from an urban site in Lahore, Pakistan. Sources of various pollutants and their...
Article
Robust knowledge on occurrence and distribution of persistent organic pollutants (POPs) in atmosphere of low-latitude regions is inevitable to forecast their transportation to pristine ecosystem and assess toxicological impacts upon local biota. Despite of the earlier revelation of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCB...
Conference Paper
Full-text available
This paper uses Normalized Difference Water Index (NDWI) of McFeeters (1996), Water Index (WI) suggested as the best by Ji, et al. (2009), referred to as Green and Short Wave Infra-Red (GSWIR) and WI introduced by Rogers and Kearney (2004), referred to as Red and Short Wave Infra-Red (RSWIR) for delineating and mapping of surface water using MODIS...
Article
Full-text available
Thoron (220 Rn), due to its-short half-life of 55.5 s is unable to travel far from its point of generation. A number of studies report indoor radon (222 Rn) concentration in different locations of Azad Jammu and Kashmir, while no study reports indoor 220 Rn concentration. The CR-39 based passive alpha track detectors were used for the measurement o...
Article
Background: Several epidemiological studies conducted on underground miner's show that exposure to elevated levels of radioactive radon gas is expected to increase the risk of lung cancer. Relative risk of lung cancer is almost linear with radon exposure. Elevated concentrations of radon are not only reported within mines but also for closed indoor...
Conference Paper
Soil moisture plays an important role for understanding hydrology and climate. Soil moisture is a key variable in hydrological process, as the availability of moisture content in soil controls the mechanism between the land surface and atmospheric processes. Accurate estimation of soil moisture is crucial in environmental studies. Soil moisture can...
Article
Concentrations and source apportionment of PM(2.5) monitored at an urban residential site in Karachi Metropolitan, Pakistan have been reported in this paper. PM(2.5) aerosol samples were collected on alternative days (three times per week) for 24-hrs duration on Zefluor(TM) filter papers using Thermo-Electron Corporation Reference Ambient Air Sampl...
Article
Full-text available
Results of indoor radon survey in the dwellings of district Bhimber are presented. Current study is continuation of our preceding studies aiming to setup baseline indoor radon data for the state of Azad Jammu & Kashmir, Pakistan. In this context, 60 representative houses were carefully selected and CN-85 based box type radon detectors were installe...
Article
Full-text available
During March and April 2010 aerosol inventories from four large cities in Pakistan were assessed in terms of particle size distributions (N), mass (M) concentrations, and particulate matter (PM) concentrations. These M and PM concentrations were obtained for Karachi, Lahore, Rawalpindi, and Peshawar from N concentrations using a native algorithm ba...
Article
Measurements of indoor radon concentrations in 200 dwellings of four districts of Azad Kashmir have been carried out using CR-39-based radon dosimeters. Indoor radon levels were calculated for four seasons (i.e. spring, summer, autumn and winter) in Muzaffarabad, Hattian, Neelum and Poonch districts. Maximum value of radon concentration (398 ± 2 Bq...
Article
Experimental results concerning the radon exhalation rate from samples of building materials which were collected from the districts of Muzaffarabad and Neelum Valley, Azad Kashmir, Pakistan are presented. The study aims at assessing the contribution of building materials towards the total indoor radon exposure to the inhabitants of the studied are...
Article
Full-text available
Radiation doses from indoor radon exposure, before and after the 2005 earthquake, have been assessed from measurements taken in the city of Muzaffarabad and Jhelum valley, Azad Kashmir, Pakistan. Indoor radon concentration was measured in dwellings in Muzaffarabad city and the Jhelum valley after the devastating 2005 earthquake using CR-39 based ra...
Article
Full-text available
An indoor radon measurement survey has been carried out in the dwellings of Balakot city of North West Frontier Province of Pakistan using CR-39 based radon detectors. The main objective of this survey was to estimate radiation doses received by the dwellers of the Balakot city due to the indoor radon exposure. For this purpose CR-39 based radon de...
Article
Full-text available
Pakistan experienced a devastating flood which originated on 22th July, 2010 from Khyber-Pukhtunkhwa and Punjab. In order to monitor the daily extent of the inundated area due to flooding medium resolution MODIS data has been used. The frequent availability and good temporal resolution MODIS data has been very effective for obtaining the first hand...
Article
Several epidemiological studies conducted on thousands of underground miners suggest that long- term exposure to high radon concentration can increase the risk of lung cancer. Keeping in view the importance of the subject, numerous studies throughout the world have been carried out to measure indoor radon concentration and its resulting doses at oc...
Article
In order to assess the effect of long term exposure, CR-39 based radon dosimeters were exposed to indoor radon in the drawing rooms (living room) of 200 selected houses of the districts of Swabi, Mardan and Charsadda in the North West Frontier Province (NWFP) as well as in the Mohmand and Bajuar Agencies of the federally administered tribal areas (...
Article
The present study deals with measurement of indoor radon concentrations in dwellings of the district Poonch of the state of Azad Jammu and Kashmir, Pakistan. In this context, CR-39-based box-type radon detectors were installed in drawing rooms and bedrooms of 80 selected houses and were exposed to indoor radon for 3 months. After exposure, the CR-3...
Article
Full-text available
Humans have always been exposed throughout their period of existence to naturally occurring ionising radiation. Specifically, naturally occurring radionuclides are present in variable amounts in our environment. To assess radiological health hazards, naturally occurring radionuclides are being measured in soil, sand, marble, bricks etc throughout t...
Article
Full-text available
Indoor radon concentrations have been measured in a limited number of dwellings in the state capital of Azad Jammu and Kashmir, Muzaffarabad city after the devastating earthquake of 2005. Radon detectors(CN-85 based box-type) were placed in the drawing rooms, bedrooms and kitchens of 35 houses, selected on the basis of their location and design as...
Article
Radon is being extensively measured all over the world due to its hazardous health effects as well as for different geological applications. In this regard, considerable studies have been conducted by different research groups in Pakistan. However, these studies are scattered and need to be combined/listed somewhere for future studies of radon in P...
Article
Radioactivity is present everywhere in soil wherefrom it migrates to vegetation and plants. These vegetation/fruits when taken as food result in transfer of the radioactivity to human beings which may cause health hazards. Therefore, information about the presence of radioactivity in vegetation, plants and soil is highly desirable. In this context,...
Article
Brick, sand, marble and cement are mainly used for the construction of dwellings in Pakistan. Therefore, knowledge of the presence of natural radioactivity in these materials is of great importance in order to assess the radiological hazards associated with them. In this context, specific activities of 226Ra, 232Th and 40K were measured in brick, s...
Article
A series of experiments were carried out to study the effect of the moisture content on the radon exhalation rate from soil, sand and brick samples that were collected from the North West Frontier Province and Federally Administered Tribal Areas of Pakistan, using CR-39-based radon dosimeters. After processing, samples were prepared by adding 15, 3...
Article
226Ra, 232Th and 40K were measured in soil samples, these were collected from different localities of the North West Frontier Province and Federally Administered Tribal Areas, Pakistan. In order to measure the specific activities in these samples P-type coaxial high purity germanium based gamma-ray spectrometer was used. Average values of the measu...
Article
Indoor radon levels have been measured in several districts, namely Swabi, Mardan and Charsadda of the North West Frontier Province as well as in the Mohmand and Bajuar Agencies of the federally administered tribal areas, using CR-39-based radon dosimeters. In order to carry out this study, 200 houses were carefully selected and season wise indoor...
Article
Indoor radon level measurement survey has been performed in several districts of the North West Frontier Province (NWFP) and federally administered tribal areas (FATA), Pakistan. These include Swabi, Mardan and Charsadda Districts of NWFP and Mohmand and Bajuar Agencies of FATA. CR-39-based National Radiological Protection Board, UK-type radon dosi...
Article
In order to characterise the building materials as an indoor radon source, knowledge of the radon exhalation rate from these materials is very important. In this regard, soil, sand and brick samples were collected from different places of the North West Frontier Province (NWFP) and Federally Administered Tribal Areas (FATA), Pakistan. The samples w...
Article
Accurate knowledge of exhalation rate plays an important role in characterization of the radon source strength in building materials and soil. It is a useful quantity to compare the relative importance of different materials and soil types. Majority of houses in Pakistan are mainly constructed from soil and sand. Therefore, studies concerning the d...
Article
Significant progress has been made in reducing the risk from exposure to radon and its progeny all over the world as a result of efforts made by different organisations which are working together to educate public about the harmful effects of radon. During the past several surveys, it was found that uneducated people were totally ignorant of radon...