Margaret Bell

Abstract: Ever growing populations in cities are associated with a major increase in road vehicles and air pollution The overall high levels of urban air pollution have been shown to be of a significant risk to city dwellers However, the impacts of very high but temporally and spatially restricted pollution, and thus exposure, are still poorly understood Conventional approaches to air quality monitoring are based on networks of static and sparse measurement stations However, these are prohibitively expensive to capture tempo-spatial heterogeneity and identify pollution hotspots, which is required for the development of robust real-time strategies for exposure control Current progress in developing low-cost micro-scale sensing technology is radically changing the conventional approach to allow real-time information in a capillary form But the question remains whether there is value in the less accurate data they generate This article illustrates the drivers behind current rises in the use of low-cost sensors for air pollution management in cities, while addressing the major challenges for their effective implementation

Abstract: Plans to build a third runway at London Heathrow (LHR) airport have been held back because of concerns that the development would lead to annual mean concentrations of nitrogen dioxide (NO 2 ) in excess of the EU Directive limit value, which must be met by 2010. The dominant effect of other sources of NO x close to the airport, primarily from road traffic, makes it difficult to detect and quantify the contribution made by the airport to local NO x and NO 2 concentrations. This work presents approaches that aim to detect and quantify the airport contribution to NO x concentrations for a network of seven measurement sites close to the airport. Two principal approaches are used. First, a graphical technique using bivariate polar plots that develops the idea of a pollution rose is used to help discriminate between different source types. The sampling uncertainties associated with the technique have been calculated through a randomised re-sampling approach. Second, the unique pattern of aircraft activity at LHR enables data filtering techniques to be used to statistically verify the presence of aircraft sources. It is shown that aircraft NO x sources can be detected to at least 2.6 km from the airport, even though the airport contribution at that distance is very small. Using these approaches, estimates have been made of the airport contribution to long-term mean concentrations of NO x and NO 2 . At the airfield boundary we estimate that approximately 27% of the annual mean NO x and NO 2 is due to airport operations. At background locations 2–3 km downwind of the airport we estimate that the upper limit of the airport contribution to be less than 15% ( 10 μg m −3 ). This work also provides approaches that would help validate and refine dispersion modelling studies used for airport assessments.

Abstract: Life cycle assessment is being accepted by the road industry to measure such key environmental impacts as the energy consumption and carbon footprint of its materials and laying processes. Previous life cycle studies have indicated that the traffic vehicles account for the majority of fuel consumption and emissions from a road. Contractors and road agencies are looking for road maintenance works that have the least overall environmental impact considering both the roadwork itself and the disrupted traffic. We review life cycle assessment studies and describe the development of a model for pavement construction and maintenance, detailing the methodology and data sources. The model is applied to an asphalt pavement rehabilitation project in the UK, and the micro-simulation program VISSIM is used to model the traffic on that road section. The simulation results are fed into a traffic emissions model and emissions from the roadwork and the traffic are compared. The additional fuel consumption and emissions by the traffic during the roadwork are significant. This indicates that traffic management at road maintenance projects should be included in the life cycle assessment analysis of such work.

Abstract: Although the metabolic complications accompanying visceral deposition of fat are well-established, the onset and extent of such fat patterning in children has not been fully documented. This has been due to the problem of computerized tomography exposing children to a prohibitive radiation risk. Nuclear magnetic resonance imaging (MRI) has provided a feasible alternative. Specifically, the purposes of this study were to use MRI (i) to assess the extent of intra-abdominal (IA) and subcutaneous abdominal (SA) fat deposition in 11-year-old boys and girls, and (ii) to identify the most useful anthropometric indicators of IA adiposity in children. Twenty-five boys and 25 girls were selected to represent, by quintiles, the body mass index range for their age. IA fat, SA fat, and total cross-sectional areas were measured from an MRI scan at the umbilicus. Body density was assessed by hydrostatic weighing, and skinfold thicknesses, circumferences and related ratios, and stage of sexual maturity were measured. Results showed that a wide variation in IA fat deposition was present with amounts ranging from 6 to 58 cm2 (mean = 17.8 +/- 10.0) for boys and 15 to 50 cm2 (mean = 24.8 +/- 8.8) for girls. Percentage of cross-sectional area taken up by visceral fat appears to be less than in normal weight adults. Fourteen children had intra-abdominal/subcutaneous abdominal fat ratios that have been associated with higher health risk in obese adults. Waist-hip circumference ratio (WHR), which is widely used as an indicator of IA deposition in adults, was not a useful predictor in these children.(ABSTRACT TRUNCATED AT 250 WORDS)

Abstract: We outline selected central results from a formative evaluation of four pilot sites in England and Wales of the Integrated Children’s System (ICS) – one part of the UK’s eGovernment strategy. We concentrate on the aspiration of the ICS towards ‘integration’ and ‘systematization’ of services within children’s services, at local and national levels. We look in turn at, the use of the ICS as a foundation for aggregate statistical profiles; the experience and views of the social workers; and the implications of ICS for social work practice as exemplified in social workers’ use of time. The evidence suggests substantial problems in accomplishing government policy aspirations in each of these areas. We review the likely reasons for these problems, and recommend a review of the ICS on the grounds that the difficulties are inherent rather than transitory, and have arisen at least in part from uncertainty as to whether the ICS is fit for purpose. The authors seek to promote the open and thoughtful debate that a major innovation of this nature requires.

Abstract: openair is an R package primarily developed for the analysis of air pollution measurement data but which is also of more general use in the atmospheric sciences. The package consists of many tools for importing and manipulating data, and undertaking a wide range of analyses to enhance understanding of air pollution data. In this paper we consider the development of the package with the purpose of showing how air pollution data can be analysed in more insightful ways. Examples are provided of importing data from UK air pollution networks, source identification and characterisation using bivariate polar plots, quantitative trend estimates and the use of functions for model evaluation purposes. We demonstrate how air pollution data can be analysed quickly and efficiently and in an interactive way, freeing time to consider the problem at hand. One of the central themes of openair is the use of conditioning plots and analyses, which greatly enhance inference possibilities. Finally, some consideration is given to future developments.

Abstract: BACKGROUND A central fat pattern has adverse health implications in both children and adults. Because adiposity tracks from childhood into adulthood, the ability of simple anthropometric techniques to correctly measure truncal adiposity in childhood needs to be assessed. OBJECTIVES We sought to assess the validity of waist circumference, waist-to-hip ratio (WHR), and the conicity index as indicators of trunk fat mass in children and adolescents. DESIGN Trunk fat mass (kg) was measured with dual-energy X-ray absorptiometry in 278 girls and 302 boys aged 3-19 y. Receiver operating characteristic (ROC) curves and areas under the curves (AUCs) for the ROCs were calculated to compare the relative abilities of the anthropometric measures to correctly identify children with high trunk fat mass (z score for our study population of > or =1). RESULTS The 80th percentile for waist circumference correctly identified 89% of girls and 87% of boys with high trunk fat mass (sensitivity) and 94% of girls and 92% of boys with low trunk fat mass (specificity). Waist circumference performed significantly better as an index of trunk fat mass than did WHR or the conicity index, as shown by the AUCs in girls and boys, respectively: waist circumference AUCs = 0.97 and 0.97, conicity index AUCs = 0.80 and 0.81, and WHR AUCs = 0.73 and 0.71. Our cutoffs for high trunk fat mass and high waist circumference are provided for both sexes for each year of age. CONCLUSION Waist circumference provides a simple yet effective measure of truncal adiposity in children and adolescents.

Abstract: The development of models to assess air pollution exposures within cities for assignment to subjects in health studies has been identified as a priority area for future research. This paper reviews models for assessing intraurban exposure under six classes, including: (i) proximity-based assessments, (ii) statistical interpolation, (iii) land use regression models, (iv) line dispersion models, (v) integrated emission-meteorological models, and (vi) hybrid models combining personal or household exposure monitoring with one of the preceding methods. We enrich this review of the modelling procedures and results with applied examples from Hamilton, Canada. In addition, we qualitatively evaluate the models based on key criteria important to health effects assessment research. Hybrid models appear well suited to overcoming the problem of achieving population representative samples while understanding the role of exposure variation at the individual level. Remote sensing and activity-space analysis will complement refinements in pre-existing methods, and with expected advances, the field of exposure assessment may help to reduce scientific uncertainties that now impede policy intervention aimed at protecting public health.

Abstract: Objective: To develop waist circumference percentile curves for British children and to compare these curves with those from other countries. Design: Cross-sectional study. Setting: School-aged population. Subjects: A representative sample of school children from the geographical regions of Great Britain, approximately in proportion to their age distribution. The sample population consisted of 8355 children (3585 males, 4770 females) with ages ranging between 5.0 and 16.9 y. Interventions: Waist circumferences were measured with a flexible non-elastic tape and waist circumference percentiles were constructed and smoothed using the LMS method. Main outcome measures: Smoothed waist circumference percentile curves. Results: Mean waist circumference increased with age in both boys and girls. For girls, curves began to plateau after the age of 13 y whereas, for boys, waist percentile curves continued to increase more sharply after this age. However, these curves mainly reflect the patterns of waist circumference in Caucasian children. Conclusions: These curves represent the first waist circumference percentiles for British children and could be used provisionally for both clinical and possibly epidemiological use, although they should be validated against equivalent longitudinal data. Sponsorship: This project has been sponsored by UNL Diversity and Development Fund. European Journal of Clinical Nutrition (2001) 55, 902–907