To date, diesel particulate matter (DPM) has been described as aggregates of spherule particles with a smooth appearing surface. We have used a new colour confocal microscope imaging method to study the 3D shape of diesel particulate matter (DPM); we observed that the particles can have sharp jagged appearing edges and consistent with these findings, 2D light microscopy demonstrated that DPM adheres to human lung epithelial cells. Importantly, the slide preparation and confocal microscopy method applied avoids possible alteration to the particles' surfaces and enables colour 3D visualisation of the particles.
View Article and Find Full Text PDFThe natural radioactive gas radon is widely present in the built environment and at high concentrations is associated with enhanced risk of lung-cancer. This risk is significantly enhanced for habitual smokers. Although populations with higher degrees of social deprivation are frequently exposed to higher levels of many health-impacting pollutants, a recent study suggests that social deprivation in the UK is associated with lower radon concentrations.
View Article and Find Full Text PDFIn this paper, the sensitivity of the structural integrity of wind turbine blades to debonding of the shear web from the spar cap was investigated. In this regard, modal analysis, static and fatigue testing were performed on a 45.7 m blade for three states of the blade: (i) as received blade (ii) when a crack of 200 mm was introduced between the web and the spar cap and (iii) when the crack was extended to 1000 mm.
View Article and Find Full Text PDFSci Total Environ
July 2017
We present initial results from a novel high resolution confocal microscopy study of the 3D surface structure of volcanic ash particles from two recent explosive basaltic eruptions, Eyjafjallajökull (2010) and Grimsvötn (2011), in Iceland. The majority of particles imaged are less than 100μm in size and include PMs, known to be harmful to humans if inhaled. Previous studies have mainly used 2D microscopy to examine volcanic particles.
View Article and Find Full Text PDFSci Total Environ
January 2017
Solid State Nuclear Track Detectors (SSNTDs) are used extensively for monitoring alpha particle radiation, neutron flux and cosmic ray radiation. Radon gas inhalation is regarded as being a significant contributory factor to lung cancer deaths in the UK each year. Gas concentrations are often monitored using CR39 based SSNTDs as the natural decay of radon results in alpha particles which form tracks in these detectors.
View Article and Find Full Text PDFInhalation of radon gas is considered a risk factor in the development of lung cancer. Solid state nuclear track detectors (SSNTDs) are often used for monitoring radon levels. We have previously shown that 3D imaging can help distinguish real tracks from artefact.
View Article and Find Full Text PDFThis study re-examines the risk to health from radium ((226)Ra) dial watches. Ambient dose equivalent rates have been measured for fifteen pocket watches giving results of up to 30 μSv h(-1) at a distance of 2 cm taken with a series 1000 mini-rad from the front face (arithmetic mean ambient dose equivalent for pocket watches being 13.2 μSv h(-1)).
View Article and Find Full Text PDFSolid state nuclear track detectors are used to determine the concentration of alpha particles in the environment. The standard method for assessing exposed detectors involves 2D image analysis. However 3D imaging has the potential to provide additional information relating to angle as well as to differentiate clustered hit sequences and possibly energy of alpha particles but this could be time consuming.
View Article and Find Full Text PDFFollowing an intensive survey of domestic radon levels in the United Kingdom (UK), the former National Radiological Protection Board (NRPB), now the Radiation Protection Division of the Health Protection Agency (HPA-RPD), established a measurement protocol and promulgated Seasonal Correction Factors applicable to the country as a whole. Radon levels in the domestic built environment are assumed to vary systematically and repeatably during the year, being generally higher in winter. The Seasonal Correction Factors therefore comprise a series of numerical multipliers, which convert a 1-month or 3-month radon concentration measurement, commencing in any month of the year, to an effective annual mean radon concentration.
View Article and Find Full Text PDFRadon is a naturally occurring radioactive gas, high levels of which are associated with geological formations such as those found in Northamptonshire and North Oxfordshire in the UK. The UK's National Radiological Protection Board have designated both districts as radon Affected Areas. Radiation levels due to radon, therefore, exceed 200 Bq m(-3), the UK's domestic Action Level, in over one percent of domestic properties.
View Article and Find Full Text PDFAnalysis of data from extended radon concentration time-series obtained from domestic and public-sector premises in the vicinity of Northampton, UK, and elsewhere, confirms that, in addition to the generally recognised climatic influences, 'Earth Tides' and 'Ocean Tidal Loading' drive periodic radon liberation via geophysically driven groundwater level variations. Regression and cross-correlation with environmental parameters showed some degree of association between radon concentration and mean temperature and rainfall. Fourier analysis of radon time-series identified periodicities of the order of 23.
View Article and Find Full Text PDFTo identify the most applicable technology for the short-term assessment of domestic radon levels, comparative assessments of a number of integrating detector types, including track-etch, electret and activated charcoal were undertaken. Thirty-four unremediated dwellings in a high-radon area were monitored using track-etch detectors exposed for one-month and three-month periods. In parallel, one-week measurements were made in the same homes at one-month intervals, using co-located track-etch, charcoal and electret detectors exposed simultaneously, while three of the homes were also monitored by continuous-sampling detectors at hourly intervals over extended periods.
View Article and Find Full Text PDFDuring the course of an investigation into domestic radon levels in Northamptonshire, two hourly sampling real-time radon detectors were operated simultaneously in separate locations 2.25 km apart in Northampton, in the English East Midlands, for a 25-week period. This period of operation encompassed the period in September 2002 during which the Dudley earthquake (magnitude - 5.
View Article and Find Full Text PDFGeology has been highlighted by a number of authors as a key factor in high indoor radon levels. In the light of this, this study examines the application of seasonal correction factors to indoor radon concentrations in the UK. This practice is based on an extensive database gathered by the National Radiological Protection Board over the years (small-scale surveys began in 1976 and continued with a larger scale survey in 1988) and reflects well known seasonal variations observed in indoor radon levels.
View Article and Find Full Text PDFJ Environ Radioact
January 2006
As part of a long-term assessment of domestic radon in Northamptonshire, England, a batch of 50 commercially available electrets was deployed for nearly 1,000 exposures, individual exposure periods ranging from one to eight weeks. Responsivity was comparable with that of recently-calibrated Durridge RAD-7 continuously-monitoring equipment. Voltage history analysis indicated mean voltage decay during manufacturers' QA assessment of 0.
View Article and Find Full Text PDFThis reconnaissance study of radon concentrations in the Great Cave of Niah in Sarawak shows that in relatively deep pits and trenches in surficial deposits largely covered by protective shelters with poor ventilation, excavators are working in a micro-environment in which radon concentrations at the ground surface can exceed those of the surrounding area by a factor of > x 2. Although radon concentrations in this famous cave are low by world standards (alpha track-etch results ranging from 100 to 3075 Bq m(-3)), they still may pose a health risk to both excavators (personal dosemeter readings varied from 0.368 to 0.
View Article and Find Full Text PDFSci Total Environ
February 2004
Concentrations of 222Rn were measured in ancient copper mines which exploited the Faynan Orefield in the South-Western Jordanian Desert. The concentrations of radon gas detected indicate that the ancient metal workers would have been exposed to a significant health risk and indicate that any future attempt to exploit the copper ores must deal with the hazard identified. Seasonal variations in radon concentrations are noted and these are linked to the ventilation of the mines.
View Article and Find Full Text PDFRadon, together with its progeny, is present in high levels in some underground sites. Radon is known to increase the risk of lung cancer, while increased levels of radon decay products on the skin surface have been implicated in skin cancer induction and at sufficient levels might cause deterministic effects such as erythema. Although radon levels in working mines are controlled, radon in abandoned mines can reach very high levels, which would result in an occupant exceeding recommended annual exposure limits in less than 2 h in some mines.
View Article and Find Full Text PDFAn investigation of radon levels in the caves of Creswell Crags, Derbyshire, an important Site of Special Scientific Interest (SSSI) shows that the Lower Magnesian Limestone (Permian) caves have moderate to raised radon gas levels (27-7800 Bq m(-3)) which generally increase with increasing distance into the caves from the entrance regions. This feature is partly explained in terms of cave ventilation and topography. While these levels are generally below the Action Level in the workplace (400 Bq m(-3) in the UK), they are above the Action Level for domestic properties (200 Bq m(-3)).
View Article and Find Full Text PDFRadon remediation programmes in domestic dwellings were carried out in five areas, from three counties of England, and the total costs obtained. A single company, which abided by the Code of Practice of the Radon Council of Great Britain, carried out the remediation. The dose savings from the programmes were calculated and used to estimate the number of lung cancers averted.
View Article and Find Full Text PDFEcotoxicol Environ Saf
July 2001
Radon levels underground in two abandoned mines in Devon, United Kingdom, are reported and analyzed. Extremely high levels have been noted, 7,100,000 Bq m(-3) being the highest level recorded. This is approximately 89 times higher than the highest published radon level for caves and mines in Devon and Cornwall, England, which is 80,000 Bq m(-3).
View Article and Find Full Text PDFEcotoxicol Environ Saf
July 2000
The concerns over the risks to human health from radon in underground caves are poorly documented, unlike in workplace or domestic environments where exposures are relatively well known. In U.K.
View Article and Find Full Text PDFIt is well established that students' evaluative ratings of instruction correlate positively with expected course grades. The authors identify 4 additional data patterns that, collectively, discriminate among 5 theories of the grades--ratings correlation. The presence of all 4 of these markers in student ratings data (obtained at University of Washington) was most consistent with the theory that the grades--ratings correlation is due to an unwanted influence of instructors' grading leniency on ratings.
View Article and Find Full Text PDFPurpose: To determine the measurement characteristics of a form used to evaluate teaching in outpatient settings, and to compare ratings received by general internists in outpatient and inpatient settings.
Method: The physicians evaluated were 29 faculty who taught in both outpatient and inpatient settings affiliated with the Department of Medicine, University of Washington School of Medicine, over a five-year period (from 1985-86 through 1989-90). Residents completed 639 evaluations, using a six-point Likert-type scale (from 1, very poor, to 6, excellent) to rate instructors in eight categories and to provide an overall assessment of each instructor's teaching effectiveness.