Publications
43 results found
Walton H, 2010, Valuing the Overall Impact of Air Pollution, Valuing the Overall Impact of Air Pollution
Walton H, 2009, Plausibility of Coefficients for Long-term Exposure and Mortality, Long-Term Exposure to Air Pollution, Editors: Ayres, Hurley, Didcot, Oxfordshire, Pages: 148-154, ISBN: 9780859516402
The Committee on the Medical Effects of Air Pollutants (COMEAP) produced in 2001 a report on the long-term effects of particulate air pollution on mortality. Research in this field has progressed rapidly since then and we present in this report a summary of the new evidence and quantitative estimates of the impact of the longterm effects of particulate pollution on mortality.We have looked in detail at the evidence linking long-term exposure to air pollutants and effects on mortality. In doing this we have assessed the possible effects of a range of factors that may affect or confound the reported associations. Whilst in this report we focus on effects on mortality, the effects of long-term exposure to air pollution on morbidity and the effects of short-term exposure to air pollution, including effects on infants, will be dealt with separately and are not covered by this report.We are left with little doubt that long-term exposure to air pollutants has an effect on mortality and thus decreases life expectancy. In this report we have recommended coefficients which, when used in conjunction with methods developed for the Department of Health and the European Commission by the Institute of Occupational Medicine, will allow calculation of the potential impact on mortality and life expectancy of specified reductions in concentrations of air pollutants.
Miller BG, Hurley JF, Walton H, et al., 2008, Quantifying Mortality Effects in Health Impact Assessments-Quantifying Attributable Deaths and/or Life Years and Their Value, 20th Annual Conference of the International-Society-for-Environmental-Epidemiology, Publisher: LIPPINCOTT WILLIAMS & WILKINS, Pages: S233-S233, ISSN: 1044-3983
Walton H, 2007, The Air Quality Strategy for England, Scotland, Wales and Northern Ireland, The Air Quality Strategy for England, Scotland, Wales and Northern Ireland, Pages: 38-40
Miller B, Hurley F, Walton H, et al., 2006, IOMLIFET: A flexible system for quantitative impact assessment of effects on mortality, ISEE/ISEA 2006 Conference, Publisher: LIPPINCOTT WILLIAMS & WILKINS, Pages: S152-S152, ISSN: 1044-3983
Johnson H, Kovats RS, McGregor G, et al., 2005, The impact of the 2003 heat wave on mortality and hospital admissions in England, Health Statistics Quarterly, Pages: 6-11, ISSN: 1465-1645
This article quantifies the impact of the heat wave, 4 to 13 August 2003, on mortality and emergency hospital admissions in England by region and age group. The August 2003 heat wave was associated with a large short-term increase in mortality, particularly in London. Overall in England there were 2,091 (17 per cent) excess deaths. Worst affected were those over the age of 75. The greatest increase of any region in England was in London in the over 75 age group with 522 excess deaths (59 per cent). Excess hospital admissions of 16 per cent were recorded in London for the over 75s. Temperatures in England were unusually hot. Ozone and particulate matter concentrations were also elevated during the heat wave. Estimated excess mortality was greater than for other recent heat waves in the UK.
Johnson H, Kovats RS, McGregor G, et al., 2005, The impact of the 2003 heat wave on daily mortality in England and Wales and the use of rapid weekly mortality estimates, Eurosurveillance, Vol: 10, Pages: 168-171, ISSN: 1025-496X
This paper describes a retrospective analysis of the impact of the 2003 heat wave on mortality in England and Wales, and compares this with rapid estimates based on the Office for National Statistics routine weekly deaths reporting system. Daily mortality data for 4 to 13 August 2003, when temperatures were much hotter than normally seen in England, were compared with averages for the same period in years 1998 to 2002. The August 2003 heat wave was associated with a large short-term increase in mortality, particularly in London. Ozone and particulate matter concentrations were also elevated during the heat wave. Overall, there were 2139 (16%) excess deaths in England and Wales. Worst affected were people over the age of 75 years. The impact was greatest in the London region where deaths in those over the age of 75 increased by 59%. Estimated excess mortality was greater than for other recent heat waves in the United Kingdom. The estimated number of deaths registered each week is reported by the Office for National Statistics. The first clear indication of a substantial increase in deaths was published on 21 August 2003. This provided a quick first estimate of the number of deaths attributable to the heat wave and reflected the pattern of daily deaths in relation to the hottest days, but underestimated the excess when compared with the later analysis.
Johnson H, Kovats S, McGregor G, et al., 2004, The impact of the 2003 heat wave on mortality and hospital admissions in England, 16th Conference of the International-Society-for-Environmental-Epidemiology, Publisher: LIPPINCOTT WILLIAMS & WILKINS, Pages: S126-S126, ISSN: 1044-3983
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Walton H, 2003, ‘Why should exposure assessment play a role in urban air quality management?, Reflections from a health perspective, WHO Regional Office for Europe, Copenhagen
European air quality policy has so far focused on ambient (outdoor) air pollution. Accordingly, European countries have put major efforts into formulating and implementing abatement strategies for outdoor sources, while indoor sources may not have been adequately taken into account. Consequently, the present approaches may not be effective in reducing the health risks linked to pollution. This workshop evaluated how appropriate the current exposure assessment methods are when designing and implementing comprehensive policies and air quality management approaches to address the health risks of air pollutants from both outdoor and indoor sources. After reviewing the presently available methods of exposure assessment, the workshop participants agreed that, for certain air pollutants, well designed outdoor air quality assessment and management approaches may be appropriate tools to reduce the health risks of pollution. However, for the strong indoor pollutants, additional information is needed to increase the efficiency of present air quality management practice and to address exposure in all microenvironments. This should include models of exposure which can be applicable in various countries, provided that the local data on emission from indoor sources are available along with, pollution concentration in various microenvironments and population activities.
Walton H, 2002, Quantification of the health effects of air pollution in the UK for revised PM10 objective analysis, Publisher: AEA Technology plc
The Air Quality Strategy for England, Wales, Scotland and Northern Ireland currently sets the following objectives for PM10 particles, to be achieved by 31 December 2004:· 50 mgm-3 as a 24-hour mean, not to be exceeded more than 35 times a year· 40 mgm-3 as an annual mean, not to be exceeded.These objectives are consistent with the Stage 1 limit values for PM10 included in the first EU Daughter Directive (AQDD), which are to be achieved by 1 January 2005. The 24-hour mean objective and limit value is expected to be the more stringent of the two. Indicative Stage 2 limit values for PM10 are also included in the first AQDD at 20 mgm-3 as an annual mean and 50mgm-3 as a 24-hour mean, not to be exceeded more than 7 times a year, to be achieved by 1January 2010.The Government and devolved administrations recognise that the possible health gains from reducing PM10 levels are thought to be greater than those for any other pollutant. They are concerned to set sights beyond the immediate need to comply with the AQDD Stage 1 limit values. The Government and devolved administrations have therefore undertaken to assess the prospects of whether the AQS objectives for PM10 can be strengthened (DETR et al, 2000). An analysis of the costs and benefits of different measures to reduce ambient PM10 concentrations forms an important part of this PM10 objective analysis.A consultation document on proposals for air quality objectives for particles, benzene, carbon monoxide and polycyclic aromatic hydrocarbons has been published (DEFRA et al, 2001a) along with an economic analysis to inform the review of the Air Quality Strategy objectives for particles (DEFRA, et al, 2001b). A series of reports detailing the air quality modelling (Stedman, et al 2001a Stedman et al, 2001b cost analysis (AEA Technology, 2001) and health benefitsanalyses (Stedman et al, 2001c supporting the review have also been published.
Wearne SJ, Gem MG, Harrison N, et al., 1996, Contaminants of food, Prioritisation scheme to identify manufactured organic chemicals as potential contaminants of food, Vol: 3, Pages: 83-88, ISSN: 0944-1344
A scheme has been developed to rank 70 industrial organic chemicals in order of their priority for further study as potential contaminants of food. Numerical scales were developed for the following seven key criteria concerning environmental issues, food and toxicity: -Production volume -Pattern of usage -Possible fate in the environment -Likelihood of chemical entering the food chain -Mechanism of entry into the food chain -Persistence and accumulation in the food chain -Toxicity. Each chemical was assigned a score for the above criteria, which were combined to give an overall ranking for the chemicals.This scheme has been endorsed by the MAFF Steering Group on Chemical Aspects of Food Surveillance. It will be used in the assessment of relative priorities for further non-statutory surveillance for these contaminants in the UK food supply.
Walton HA, Byrne J, Robinson GB, 1992, Studies of the permeation properties of glomerular basement membrane, cross-linking renders glomerular basement membrane permeable to protein, Vol: 1138, Pages: 173-183, ISSN: 0006-3002
Cross-linking glomerular basement membrane (GBM) has been shown to render it more permeable to protein. Isolated pig GBM was cross-linked with dimethylmalonimidate which reacts selectively with lysine epsilon-NH2 groups or with glutaraldehyde, a less selective cross-linking agent. Studies of the ultrafiltration properties of these materials in vitro using cytochrome c, myoglobin, bovine serum albumin and immunoglobulin showed that cross-linking had markedly increased solvent and protein fluxes as compared with native membranes particularly at higher pressures. Filtration studies with serum demonstrated that the cross-linked membranes were more permeable to serum proteins. Thickness measurements under pressure indicated that cross-linked membrane was less compressed than native membrane as pressure was increased. Pore theory did not provide a suitable model for analysis of the results, but analysis of the results using the fibre-matrix hypothesis indicated that cross-linking had the effect of bundling together the fibres (type IV collagen) in the GBM matrix. The effect of cross-linking on filtration could be explained by a combination of contraction of the membrane, fibre bundling and increased rigidity compared with native membrane. Cross-linking of GBM might lead to long-term damage of the glomerular capillary wall in nephritis, so promoting proteinuria.
Robinson GB, Walton HA, 1989, Glomerular basement membrane as a compressible ultrafilter, Microvascular Research, Vol: 38, Pages: 36-48, ISSN: 0026-2862
The ultrafiltration properties of isolated glomerular basement membrane were studied in vitro by forming membrane fragments into thin films for use as ultrafiltration membranes. The filtration properties of the films were examined using cytochrome c, myoglobin, lysozyme, ovalbumin, lactoglobulin, and serum albumin. The films behaved as compressible filters showing size-dependent rejection of the proteins. The behavior of the films was modelled using the fiber matrix hypothesis which gave good prediction of film behavior. The membrane behaved as a random fiber matrix composed of fibers of 0.8-1.0 nm in radius.
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