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Rivas I, Vicens L, Basagaña X, et al., 2021, Associations between sources of particle number and mortality in four European cities, Environment International, Vol: 155, ISSN: 0160-4120
BACKGROUND: The evidence on the association between ultrafine (UFP) particles and mortality is still inconsistent. Moreover, health effects of specific UFP sources have not been explored. We assessed the impact of UFP sources on daily mortality in Barcelona, Helsinki, London, and Zurich. METHODS: UFP sources were previously identified and quantified for the four cities: daily contributions of photonucleation, two traffic sources (fresh traffic and urban, with size mode around 30 nm and 70 nm, respectively), and secondary aerosols were obtained from data from an urban background station. Different periods were investigated in each city: Barcelona 2013-2016, Helsinki 2009-2016, London 2010-2016, and Zurich 2011-2014. The associations between total particle number concentrations (PNC) and UFP sources and daily (natural, cardiovascular [CVD], and respiratory) mortality were investigated using city-specific generalized linear models (GLM) with quasi-Poisson regression. RESULTS: We found inconsistent results across cities, sources, and lags for associations with natural, CVD, and respiratory mortality. Increased risk was observed for total PNC and natural mortality in Helsinki (lag 2; 1.3% [0.07%, 2.5%]), CVD mortality in Barcelona (lag 1; 3.7% [0.17%, 7.4%]) and Zurich (lag 0; 3.8% [0.31%, 7.4%]), and respiratory mortality in London (lag 3; 2.6% [0.84%, 4.45%]) and Zurich (lag 1; 9.4% [1.0%, 17.9%]). A similar pattern of associations between health outcomes and total PNC was followed by the fresh traffic source, for which we also found the same associations and lags as for total PNC. The urban source (mostly aged traffic) was associated with respiratory mortality in Zurich (lag 1; 12.5% [1.7%, 24.2%]) and London (lag 3; 2.4% [0.90%, 4.0%]) while the secondary source was associated with respiratory mortality in Zurich (lag 1: 12.0% [0.63%, 24.5%]) and Helsinki (4.7% [0.11%, 9.5%]). Reduced risk for the photonucleation source was observed for respiratory mortalit
Evangelopoulos D, Katsouyanni K, Schwartz J, et al., 2021, Quantifying the short-term effects of air pollution on health in the presence of exposure measurement error: A simulation study of multi-pollutant model results, Environmental Health: A Global Access Science Source, Vol: 20, Pages: 1-13, ISSN: 1476-069X
Background: Most epidemiological studies estimate associations without considering exposure measurement error. While some studies have estimated the impact of error in single-exposure models we aimed to quantify the effect of measurement error in multi-exposure models, specifically in time-series analysis of PM2.5, NO2,and mortality using simulations, under various plausible scenarios for exposure errors. Measurement error in multi-exposure models can lead to effect transfer where the effect estimate is overestimated for the pollutant estimated with more error to the one estimated with less error. This complicates interpretation of the independent effects of different pollutants and thus the relative importance of reducing their concentrations in air pollution policy. Methods: Measurement error was defined as the difference between ambient concentrations and personal exposure from outdoor sources. Simulation inputs for error magnitude and variability were informed by the literature. Error-free exposures with their consequent health 16outcome and error-prone exposures of various error types (classical/Berkson) were generated. Bias was quantified as the relative difference in effect estimates of the error-free and error-prone exposures. Results: Mortality effect estimates were generally underestimated with greater bias observed when low ratios of the true exposure variance over the error variance were assumed (27.4% 21underestimation for NO2). Higher ratios resulted in smaller, but still substantial bias (up to 19% for both pollutants).Effect transfer was observed indicating that less precise measurements for one pollutant (NO2) yield more bias, while the co-pollutant(PM2.5) associations were found closer to the true. Interestingly, the sum of single-pollutant model effect estimates was found closer to the summed true associations than those from multi-pollutant models, due to cancelling out of confounding and measurement error bias.Conclusions: Our simulation study i
Evangelopoulos D, Chatzidiakou L, Walton H, et al., 2021, Personal exposure to air pollution and respiratory health of COPD patients in London, European Respiratory Journal, Vol: 58, ISSN: 0903-1936
Previous studies have investigated the effects of air pollution on chronic obstructive pulmonary disease (COPD) patients using either fixed site measurements or a limited number of personal measurements, usually for one pollutant and a short time period. These limitations may introduce bias and distort the epidemiological associations as they do not account for all the potential sources or the temporal variability of pollution.We used detailed information on individuals' exposure to various pollutants measured at fine spatio-temporal scale to obtain more reliable effect estimates. A panel of 115 patients was followed up for an average continuous period of 128 days carrying a personal monitor specifically designed for this project that measured temperature, PM10, PM2.5, NO2, NO, CO and O3 at one-minute time resolution. Each patient recorded daily information on respiratory symptoms and measured peak expiratory flow (PEF). A pulmonologist combined related data to define a binary variable denoting an "exacerbation". The exposure-response associations were assessed with mixed-effects models.We found that gaseous pollutants were associated with a deterioration in patients' health. We observed an increase of 16.4% (95% confidence interval: 8.6-24.6%), 9.4% (5.4-13.6%) and 7.6% (3.0-12.4%) in the odds of exacerbation for an interquartile range increase in NO2, NO and CO respectively. Similar results were obtained for cough and sputum. O3 was found to have adverse associations with PEF and breathlessness. No association was observed between particles and any outcome.Our findings suggest that, when considering total personal exposure to air pollutants, mainly the gaseous pollutants affect COPD patients' health.
Evangelopoulos D, Perez-Velasco R, Walton H, et al., 2020, The role of burden of disease assessment in tracking progress towards achieving WHO global air quality guidelines, International Journal of Public Health, Vol: 65, Pages: 1455-1465, ISSN: 0303-8408
OBJECTIVES: More than 90% of the global population live in areas exceeding the PM2.5 air quality guidelines (AQGs). We provide an overview of the ambient PM2.5-related burden of disease (BoD) studies along with scenario analysis in the framework of the WHO AQG update on the estimated reduction in the BoD if AQGs were achieved globally. METHODS: We reviewed the literature for large-scale studies for the BoD attributed to ambient PM2.5. Moreover, we used the latest WHO statistics to calculate the BoD at current levels and the scenarios of aligning with interim targets and AQG levels. RESULTS: The most recent BoD studies (2010 onwards) share a similar methodology, but there are differences in the input data which affect the estimates for attributable deaths (2.9-8.9 million deaths annually). Moreover, we found that if AQGs were achieved, the estimated BoD would be reduced by up to 50% in total deaths worldwide. CONCLUSIONS: Understanding the BoD across countries, especially in those that do not align with the AQGs, is essential in order to inform actions to reduce air pollution globally.
Gowers AM, Walton H, Exley KS, et al., 2020, Using epidemiology to estimate the impact and burden of exposure to air pollutants, PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES, Vol: 378, ISSN: 1364-503X
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Floyd CN, Shahed F, Ukah F, et al., 2020, Acute blood pressure-lowering effects of nitrogen dioxide exposure from domestic gas cooking via elevation of plasma nitrite concentration in healthy individuals, Circulation Research, Vol: 127, Pages: 847-848, ISSN: 0009-7330
Evangelopoulos D, Katsouyanni K, Keogh RH, et al., 2020, PM2.5 and NO2 exposure errors using proxy measures, including derived personal exposure from outdoor sources: A systematic review and meta-analysis, Environment International, Vol: 137, ISSN: 0160-4120
BACKGROUND: The use of proxy exposure estimates for PM2.5 and NO2 in air pollution studies instead of personal exposures, introduces measurement error, which can produce biased epidemiological effect estimates. Most studies consider total personal exposure as the gold standard. However, when studying the effects of ambient air pollution, personal exposure from outdoor sources is the exposure of interest. OBJECTIVES: We assessed the magnitude and variability of exposure measurement error by conducting a systematic review of the differences between personal exposures from outdoor sources and the corresponding measurements for ambient concentrations in order to increase understanding of the measurement error structures of the pollutants. DATA SOURCES AND ELIGIBILITY CRITERIA: We reviewed the literature (ISI Web of Science, Medline, 2000-2016) for English language studies (in any age group in any location (NO2) or Europe and North America (PM2.5)) that reported repeated measurements over time both for personal and ambient PM2.5 or NO2 concentrations. Only a few studies reported personal exposure from outdoor sources. We also collected data for infiltration factors and time-activity patterns of the individuals in order to estimate personal exposures from outdoor sources in every study. STUDY APPRAISAL AND SYNTHESIS METHODS: Studies using modelled rather than monitored exposures were excluded. Type of personal exposure monitor was assessed. Random effects meta-analysis was conducted to quantify exposure error as the mean difference between "true" and proxy measures. RESULTS: Thirty-two papers for PM2.5 and 24 for NO2 were identified. Outdoor sources were found to contribute 44% (range: 33-55%) of total personal exposure to PM2.5 and 74% (range: 57-88%) to NO2. Overall estimates of personal exposure (24-hour averages) from outdoor sources were 9.3 μg/m3 and 12.0 ppb for PM2.5 and NO2 respectively, while the corresponding difference between these expo
D'Antoni D, Auyeung V, Walton H, et al., 2019, The effect of evidence and theory-based health advice accompanying smartphone air quality alerts on adherence to preventative recommendations during poor air quality days, A randomised controlled trial, Vol: 124, Pages: 216-235, ISSN: 0160-4120
Although poor air quality can have a negative impact on human health, studies have shown suboptimal levels of adherence to health advice associated with air quality alerts. The present study compared the behavioural impact of the UK Air Quality Index (DAQI) with an alternative message format, using a 2 (general population vs. at-risk individuals) X 2 (usual DAQI messages vs. behaviourally enhanced messages) factorial design. Messages were sent via a smartphone application. Eighty-two participants were randomly allocated to the experimental groups. It was found that the enhanced messages (targeting messages specificity and psychosocial predictors of behaviour change) increased intentions to make permanent behavioural changes to reduce exposure, compared to the control group (V = 0.23). This effect was mediated by a reduced perception of not having enough time to follow the health advice received (b = −0.769, BCa CI [−2.588, 0.533]). It was also found that higher worry about air pollution, perceived severity, perceived efficacy of the recommended behaviour and self-efficacy were predictive of self-reported behaviour change at four weeks. In response to a real moderate air quality alert, among those with a pre-existing lung condition, more respondents in the intervention group reported to have used their preventer inhaler compared to the control group (V = 0.49). On the other hand, the two message formats performed similarly when intentions were collected in relation to a hypothetical high air pollution scenario, with all groups showing relatively high intentions to change behaviours. This study expands the currently limited understanding of how to improve the behavioural impact of existing air quality alerts.
Williams ML, Beevers S, Kitwiroon N, et al., 2018, Public health air pollution impacts of pathway options to meet the 2050 UK Climate Change Act target: a modelling study, Public Health Research, Vol: 6, Pages: 1-124, ISSN: 2050-4381
BackgroundThe UK’s Climate Change Act 2008 (CCA; Great Britain. Climate Change Act 2008. Chapter 27. London: The Stationery Office; 2008) requires a reduction of 80% in carbon dioxide-equivalent emissions by 2050 on a 1990 base. This project quantified the impact of air pollution on health from four scenarios involving particulate matter of ≤ 2.5 µm (PM2.5), nitrogen dioxide (NO2) and ozone (O3). Two scenarios met the CCA target: one with limited nuclear power build (nuclear replacement option; NRPO) and one with no policy constraint on nuclear (low greenhouse gas). Another scenario envisaged no further climate actions beyond those already agreed (‘baseline’) and the fourth kept 2011 concentrations constant to 2050 (‘2011’).MethodsThe UK Integrated MARKAL–EFOM System (UKTM) energy system model was used to develop the scenarios and produce projections of fuel use; these were used to produce air pollutant emission inventories for Great Britain (GB) for each scenario. The inventories were then used to run the Community Multiscale Air Quality model ‘air pollution model’ to generate air pollutant concentration maps across GB, which then, combined with relationships between concentrations and health outcomes, were used to calculate the impact on health from the air pollution emitted in each scenario. This is a significant improvement on previous health impact studies of climate policies, which have relied on emissions changes. Inequalities in exposure in different socioeconomic groups were also calculated, as was the economic impact of the pollution emissions.ResultsConcentrations of NO2 declined significantly because of a high degree of electrification of the GB road transport fleet, although the NRPO scenario shows large increases in oxides of nitrogen emissions from combined heat and power (CHP) sources. Concentrations of PM2.5 show a modest decrease by 2050, which would have been larger if it had n
Williams ML, Lott MC, Kitwiroon N, et al., 2018, The Lancet Countdown on health benefits from the UK Climate Change Act, a modelling study for Great Britain, Vol: 2, Pages: e202-e213, ISSN: 2542-5196
Background Climate change poses a dangerous and immediate threat to the health of populations in the UK and worldwide. We aimed to model different scenarios to assess the health co-benefits that result from mitigation actions. Methods In this modelling study, we combined a detailed techno-economic energy systems model (UK TIMES), air pollutant emission inventories, a sophisticated air pollution model (Community Multi-scale Air Quality), and previously published associations between concentrations and health outcomes. We used four scenarios and focused on the air pollution implications from fine particulate matter (PM2·5), nitrogen dioxide (NO2) and ozone. The four scenarios were baseline, which assumed no further climate actions beyond those already achieved and did not meet the UK's Climate Change Act (at least an 80% reduction in carbon dioxide equivalent emissions by 2050 compared with 1990) target; nuclear power, which met the Climate Change Act target with a limited increase in nuclear power; low-greenhouse gas, which met the Climate Change Act target without any policy constraint on nuclear build; and a constant scenario that held 2011 air pollutant concentrations constant until 2050. We predicted the health and economic impacts from air pollution for the scenarios until 2050, and the inequalities in exposure across different socioeconomic groups. Findings NO2 concentrations declined leading to 4 892 000 life-years saved for the nuclear power scenario and 7 178 000 life-years saved for the low-greenhouse gas scenario from 2011 to 2154. However, the associations that we used might overestimate the effects of NO2 itself. PM2·5 concentrations in Great Britain are predicted to decrease between 42% and 44% by 2050 compared with 2011 in the scenarios that met the Climate Change Act targets, especially those from road traffic and off-road machinery. These reductions in PM2·5 are tempered by a 2035 peak (and subsequent decline) in biomass (wood bu
Héroux M-E, Anderson HR, Atkinson R, et al., 2017, Response to: Premature deaths attributed to ambient air pollutants: let us interpret the Robins-Greenland theorem correctly, International Journal of Public Health, Vol: 62, Pages: 339-341, ISSN: 0303-8408
Maiheu B, Lefebvre W, Walton HA, et al., 2017, Improved Methodologies for NO2 Exposure Assessment in the EU, Publisher: European Commission
Bino M, Lefebvre W, Walton H, et al., 2017, Sensitivity analyses regarding NO2 exposure assessment and health impacts at a European scale, 18th International Conference on Harmonisation within Atmospheric Dispersion Modelling for Regulatory Purposes
Currently, no adequate methodology exists to assess the NO2 health impacts at an EU-wide level. To a large extent this is attributed to the level of detail required in the NO2 concentration assessment at EU-level due to the strong spatial gradients for NO2 around roads. In this contribution we present a sensitivity analysis of the major sources of uncertainty in such an EU-wide health impact assessment for NO2. We do this by means of a number of bottom-up NO2 assessment maps contributed through the FAIRMODE composite mapping platform. We investigate the impact of the spatial resolution of the NO2 assessment, the available dose response curves and a number of ancillary datasets such as gridded population. We find that the largest source of uncertainty is found in the divergence between the different CRF’s available, in particular the choice of a ‘cut-off’ or ‘threshold’. For some cities, such as London, the difference is relatively small. However, the difference for smaller cities, such as Klagenfurt can go up to a factor of 6. Spatial resolution of the air quality maps and population maps is an important factor and depending on the concentration response function, the sensitivity is stronger. This work has been performed in the framework of the DG-ENV service contract 070201/2015/SER/717473/C.3, the conclusions of which contributed to the development of an EU-wide high resolution NO2 exposure assessment methodology.
Smith JD, Mitsakou C, Kitwiroon N, et al., 2016, London hybrid exposure model: improving human exposure estimates to NO2 and PM2.5 in an urban setting, Environmental Science and Technology (Washington), Vol: 50, Pages: 11760-11768, ISSN: 0013-936X
Here we describe the development of the London Hybrid Exposure Model (LHEM), which calculates exposure of the Greater London population to outdoor air pollution sources, in-buildings, in-vehicles and outdoors, using survey data of when and where people spend their time. For comparison and to estimate exposure misclassification we compared Londoners LHEM exposure with exposure at the residential address, a commonly used exposure metric in epidemiological research. In 2011, the mean annual LHEM exposure to outdoor sources was estimated to be 37÷ lower for PM2.5 and 63÷ lower for NO2 than at the residential address. These decreased estimates reflect, the effects of reduced exposure indoors, the amount of time spent indoors (95÷), and the mode and duration of travel in London. We find that an individual's exposure to PM2.5 and NO2 outside their residential address is highly correlated (Pearson's R of 0.9). In contrast, LHEM exposure estimates for PM2.5 and NO2 suggest that the degree of correlation is influe...
Héroux M, Brunekreef B, Anderson HR, et al., 2016, Response to "Quantifying the health impacts of ambient air pollutants, International Journal of Public Health, Vol: 61, Pages: 387-388, ISSN: 0303-8408
Atkinson RW, Butland BK, Dimitroulopoulou C, et al., 2016, Long-term exposure to ambient ozone and mortality: A quantitative systematic review and meta-analysis of evidence from cohort studies, BMJ Open, Vol: 6, ISSN: 2044-6055
Objectives: While there is good evidence for associations between short-term exposure to ozone and a range of adverse health outcomes, the evidence from narrative reviews for long-term exposure is suggestive of associations with respiratory mortality only. We conducted a systematic, quantitative evaluation of the evidence from cohort studies, reporting associations between long-term exposure to ozone and mortality. Methods: Cohort studies published in peer-reviewed journals indexed in EMBASE and MEDLINE to September 2015 and PubMed to October 2015 and cited in reviews/key publications were identified via search strings using terms relating to study design, pollutant and health outcome. Study details and estimate information were extracted and used to calculate standardised effect estimates expressed as HRs per 10 ppb increment in long-term ozone concentrations. Results: 14 publications from 8 cohorts presented results for ozone and all-cause and cause-specific mortality. We found no evidence of associations between long-term annual O3 concentrations and the risk of death from all causes, cardiovascular or respiratory diseases, or lung cancer. 4 cohorts assessed ozone concentrations measured during the warm season. Summary HRs for cardiovascular and respiratory causes of death derived from 3 cohorts were 1.01 (95% CI 1.00 to 1.02) and 1.03 (95% CI 1.01 to 1.05) per 10 ppb, respectively. Conclusions: Our quantitative review revealed a paucity of independent studies regarding the associations between long-term exposure to ozone and mortality. The potential impact of climate change and increasing anthropogenic emissions of ozone precursors on ozone levels worldwide suggests further studies of the long-term effects of exposure to high ozone levels are warranted.
Maiheu B, Williams ML, Walton HA, et al., 2016, Interim Report (D1) – v0.30 Service Contract on Improved Tools for Assessing NO2 Exposure (EU ambient air quality policy) Task 1 Interim Report: Review of Existing Methodologies, Publisher: European Commission
EXECUTIVE SUMMARYIntroduction and BackgroundHealth impacts attributable to elevated concentrations of NO2 in the ambient air are of increasing societal concern: the European Environment Agency (EEA) estimates this to be in the order of more than 70.000 premature deaths across the EU-28 in the year 2012 alone (EEA, 2015). However, the current European Commission's Clean Air Policy Package does not include the health impacts of NO2 exposure mainly because of the current lack of a robust methodology or tool for the assessment of NO2 exposure, and the use of appropriate dose-response relationships.DG ENV has commissioned VITO (BE) and King's College London (UK) to propose methods and tools that are coherent with exposure metrics used when deriving the appropriate concentration-response relationships and compatible with currently used integrated assessment modelling (IAM) tools in the EU. The ultimate objective of the contract is to develop a (or refine an existing) module for improved NO2 exposure calculation for health impact assessment and cost benefit analysis.This report is a key deliverable in the project and provides an overview and analysis of the main methods and tools currently used for assessing human exposure to NO2. One of its main purposes was to serve as input for an expert consultation workshop which took place at the WHO offices in Bonn on the 17th May 2016. This version has been updated to include the key recommendations and conclusions from that workshop.NO2 Health Impact AssessmentA recent review of health effects by WHO in support of the European Commission 2013 Clean Air Policy Package, REVIHAAP (World Health Organization, 2013a) has concluded that evidence for the effects of long-term exposures to NO2 independent of those of PM has now strengthened. A subsequent exercise, HRAPIE, (World Health Organization, 2013b) recommended concentration-response functions (CRFs) relating mortality outcomes to long-term (annual mean) exposure to NO2 to be used in
Walton HA, Anderson HR, Mills IC, et al., 2015, Quantifying the health impacts of ambient air pollutants: recommendations of a WHO/Europe project, International Journal of Public Health, Vol: 60, Pages: 619-627, ISSN: 0303-8408
ObjectiveQuantitative estimates of air pollution health impacts have become an increasingly critical input to policy decisions. The WHO project “Health risks of air pollution in Europe—HRAPIE” was implemented to provide the evidence-based concentration–response functions for quantifying air pollution health impacts to support the 2013 revision of the air quality policy for the European Union (EU).MethodsA group of experts convened by WHO Regional Office for Europe reviewed the accumulated primary research evidence together with some commissioned reviews and recommended concentration–response functions for air pollutant–health outcome pairs for which there was sufficient evidence for a causal association.ResultsThe concentration–response functions link several indicators of mortality and morbidity with short- and long-term exposure to particulate matter, ozone and nitrogen dioxide. The project also provides guidance on the use of these functions and associated baseline health information in the cost–benefit analysis.ConclusionsThe project results provide the scientific basis for formulating policy actions to improve air quality and thereby reduce the burden of disease associated with air pollution in Europe.
Mills IC, Atkinson RW, Kang S, et al., 2015, Quantitative systematic review of the associations between short-term exposure to nitrogen dioxide and mortality and hospital admissions, BMJ Open, Vol: 5, ISSN: 2044-6055
BACKGROUND: Short-term exposure to NO2 has been associated with adverse health effects and there is increasing concern that NO2 is causally related to health effects, not merely a marker of traffic-generated pollution. No comprehensive meta-analysis of the time-series evidence on NO2 has been published since 2007.OBJECTIVE: To quantitatively assess the evidence from epidemiological time-series studies published worldwide to determine whether and to what extent short-term exposure to NO2 is associated with increased numbers of daily deaths and hospital admissions.DESIGN: We conducted a quantitative systematic review of 204 time-series studies of NO2 and daily mortality and hospital admissions for several diagnoses and ages, which were indexed in three bibliographic databases up to May 2011. We calculated random-effects estimates by different geographic regions and globally, and also tested for heterogeneity and small study bias.RESULTS: Sufficient estimates for meta-analysis were available for 43 cause-specific and age-specific combinations of mortality or hospital admissions (25 for 24 h NO2 and 18 of the same combinations for 1 h measures). For the all-age group, a 10 µg/m(3) increase in 24 h NO2 was associated with increases in all-cause, cardiovascular and respiratory mortality (0.71% (95% CI 0.43% to 1.00%), 0.88% (0.63% to 1.13%) and 1.09% (0.75% to 1.42%), respectively), and with hospital admissions for respiratory (0.57% (0.33% to 0.82%)) and cardiovascular (0.66% (0.32% to 1.01%)) diseases. Evidence of heterogeneity between geographical region-specific estimates was identified in more than half of the combinations analysed.CONCLUSIONS: Our review provides clear evidence of health effects associated with short-term exposure to NO2 although further work is required to understand reasons for the regional heterogeneity observed. The growing literature, incorporating large multicentre studies and new evidence from less well-studied regions of the world, sup
Walton HA, Dajnak D, Beevers SD, et al., 2015, Understanding the Health Impacts of Air Pollution in London, Publisher: Transport for London and the Greater London Authority
A new report, published by the Mayor of London, is the world’s first to quantify the health effects of nitrogen dioxide, finding that up to 9,500 people die early each year in London due to long-term exposure to air pollution. This is more than twice as many as previously thought. Report author, Dr Heather Walton, Environmental Research Group, said: The evidence on the health effects of nitrogen dioxide has strengthened in recent years, including evidence linking long-term exposure to nitrogen dioxide with mortality. It is now thought that there is an additional effect beyond that previously quantified for the effects of long-term exposure to PM2.5. This report quantifies the possible maximum size of this additional effect in London in 2010, expressed as loss of life years and equivalent deaths, acknowledging uncertainties such as the contribution from traffic pollutants other than NO2.’
Atkinson R, Mills I, Walton H, et al., 2015, Fine particle components and health—a systematic review and meta-analysis of epidemiological time series studies of daily mortality and hospital admissions, Journal of Exposure Science and Environmental Epidemiology, Vol: 25, Pages: 208-214, ISSN: 1559-0631
Short-term exposure to fine particle mass (PM) has been associated with adverse health effects, but little is known about the relative toxicity of particle components. We conducted a systematic review to quantify the associations between particle components and daily mortality and hospital admissions. Medline, Embase and Web of Knowledge were searched for time series studies of sulphate (SO42−), nitrate (NO3−), elemental and organic carbon (EC and OC), particle number concentrations (PNC) and metals indexed to October 2013. A multi-stage sifting process identified eligible studies and effect estimates for meta-analysis. SO42−, NO3−, EC and OC were positively associated with increased all-cause, cardiovascular and respiratory mortality, with the strongest associations observed for carbon: 1.30% (95% CI: 0.17%, 2.43%) increase in all-cause mortality per 1 μg/m3. For PNC, the majority of associations were positive with confidence intervals that overlapped 0%. For metals, there were insufficient estimates for meta-analysis. There are important gaps in our knowledge of the health effects associated with short-term exposure to particle components, and the literature also lacks sufficient geographical coverage and analyses of cause-specific outcomes. The available evidence suggests, however, that both EC and secondary inorganic aerosols are associated with adverse health effects.
Atkinson R, Kang S, Anderson R, et al., 2014, Epidemiological time series studies of PM2.5 and daily mortality and hospital admissions: a systematic review and meta-analysis, a systematic review and meta-analysis, Vol: 69, Pages: 660-665, ISSN: 0040-6376
Background: Short-term exposure to outdoor fine particulate matter (particles with a median aerodynamic diameter <2.5 μm (PM2.5)) air pollution has been associated with adverse health effects. Existing literature reviews have been limited in size and scope.Methods: We conducted a comprehensive, systematic review and meta-analysis of 110 peer-reviewed time series studies indexed in medical databases to May 2011 to assess the evidence for associations between PM2.5 and daily mortality and hospital admissions for a range of diseases and ages. We stratified our analyses by geographical region to determine the consistency of the evidence worldwide and investigated small study bias.Results: Based upon 23 estimates for all-cause mortality, a 10 µg/m3 increment in PM2.5 was associated with a 1.04% (95% CI 0.52% to 1.56%) increase in the risk of death. Worldwide, there was substantial regional variation (0.25% to 2.08%). Associations for respiratory causes of death were larger than for cardiovascular causes, 1.51% (1.01% to 2.01%) vs 0.84% (0.41% to 1.28%). Positive associations with mortality for most other causes of death and for cardiovascular and respiratory hospital admissions were also observed. We found evidence for small study bias in single-city mortality studies and in multicity studies of cardiovascular disease.Conclusions: The consistency of the evidence for adverse health effects of short-term exposure to PM2.5 across a range of important health outcomes and diseases supports policy measures to control PM2.5 concentrations. However, reasons for heterogeneity in effect estimates in different regions of the world require further investigation. Small study bias should also be considered in assessing and quantifying health risks from PM2.5.
Favarato G, Anderson R, Atkinson R, et al., 2014, Traffic-related pollution and asthma prevalence in children. Quantification of associations with nitrogen dioxide, Air quality atmosphere and health, Vol: 7, Pages: 459-466, ISSN: 1873-9318
Ambient nitrogen dioxide is a widely available measure of traffic-related air pollution and is inconsistently associated with the prevalence of asthma symptoms in children. The use of this relationship to evaluate the health impact of policies affecting traffic management and traffic emissions is limited by the lack of a concentration-response function based on systematic review and meta-analysis of relevant studies. Using systematic methods, we identified papers containing quantitative estimates for nitrogen dioxide and the 12 month period prevalence of asthma symptoms in children in which the exposure contrast was within-community and dominated by traffic pollution. One estimate was selected from each study according to an a priori algorithm. Odds ratios were standardised to 10 μg/m3 and summary estimates were obtained using random- and fixed-effects estimates. Eighteen studies were identified. Concentrations of nitrogen dioxide were estimated for the home address (12) and/or school (8) using a range of methods; land use regression (6), study monitors (6), dispersion modelling (4) and interpolation (2). Fourteen studies showed positive associations but only two associations were statistically significant at the 5 % level. There was moderate heterogeneity (I2 = 32.8 %) and the random-effects estimate for the odds ratio was 1.06 (95 % CI 1.00 to 1.11). There was no evidence of small study bias. Individual studies tended to have only weak positive associations between nitrogen dioxide and asthma prevalence but the summary estimate bordered on statistical significance at the 5 % level. Although small, the potential impact on asthma prevalence could be considerable because of the high level of baseline prevalence in many cities. Whether the association is causal or indicates the effects of a correlated pollutant or other confounders, the estimate obtained by the meta-analysis would be appropriate for estimating impacts of traffic pollution on asthma pr
Walton HA, Atkinson R, Mills IC, et al., 2014, Quantitative systematic review of the associations between short-term exposure to ambient ozone and mortality and hospital admissions., Systematic Review and Quantitative Meta-analysis of the Evidence for Associations between Chronic and Short-term Exposure to Outdoor Air Pollutants and Health Department of Health Policy Research Programme Project: 002/0037, Publisher: St Georges, University of London
A consensus view of the ozone time-series literature can be hard to discern as it is fragmented across different averaging times and seasons. This chapter presents the results of a systematic review and meta-analysis of mortality and hospital admission studies, structured to enable comparison of coherence across age-groups and averaging times. This is the mostrecent meta-analysis covering a full range of outcomes, combining both single- and multi-city estimates and analyzing regional variations.Methods: Medline, Embase and Web of Knowledge were searched for time-series studies on ozone, indexed to May 2011. A sifting process identified eligible single-pollutant, all year effect estimates on mortality and hospital admissions for meta-analysis, avoiding duplication by location. Single and multi-city estimates were pooled, to give summary estimates by averaging time and region. Results are expressed as 1000*ln(relative risk).Results: 182 time series studies on mortality or hospital admissions provided all year, single pollutant effect estimates. Averaging times used in the studies varied by region. 8-hour O3 was positively associated with increases in all-cause mortality: 0.34 (95% CI: 0.12, 0.56), with analogous results for 1-hour (but confidence intervals spanned zero), and 24-hour measures. Associations with cardiovascular mortality were positive, with confidence intervals above zero, for all three averaging times and supported by positive results for cardiac or stroke mortality. The associations with respiratory mortality were positive across averaging times and supported by results for mortality from specific respiratory diseases. Evidence of small study bias was found in a few of the mortality analyses, but did not affect the qualitative conclusions. 8-hour O3 was positively associated with increases in cardiovascular admissions of 0.11 ( CI -0.06, 0.27).Results were not consistent by age group or supported by clear results with more specific cardiovascular disea
Project H, Walton H, 2013, Health Risks of Air Pollution in Europe HRAPIE Project, Denmark, Publisher: World Health Organistion
This document presents recommendations for concentration–response functions for key pollutants to be included in cost–benefit analysis supporting the revision of the European Union’s air quality policy. It provides a response to a question posed by the European Commission in the framework of the WHO “Health risks of air pollution in Europe – HRAPIE” project. The essential background to this response was developed through a review of evidence on health aspects of air pollutants summarized by an earlier WHO project, “Review of evidence on health aspects of air pollution – REVIHAAP”. This report recommends concentration–response functions and associated background information for several mortality and morbidity effects associated with short- and long-term exposure to particulate matter, ozone and nitrogen dioxide.This publication arises from the HRAPIE project and was co-funded by the European Union.
Kelly FJ, Fuller G, Walton HA, et al., 2012, Monitoring air pollution, use of early warning systems for public health, Vol: 17, Pages: 7-19, ISSN: 1323-7799
Research confirming the detrimental impact poor ambient air quality and episodes of abnormally high pollutants has on public health, plus differential susceptibility, calls for improved understanding of this complex topic among all walks of society. The public and particularly, vulnerable groups, should be aware of their quality of air, enabling action to be taken in the event of increased pollution. Policy makers must have a sound awareness of current air quality and future trends, to identify issues, guide policies and monitor their effectiveness. These attitudes are dependent upon air pollution monitoring, forecasting and reporting, serving all interested parties. Apart from the underlying national regulatory obligation a country has in reporting air quality information, data output serves several purposes. This review focuses on provision of real-time data and advanced warnings of potentially health-damaging events, in the form of national air quality indices and proactive alert services. Some of the challenges associated with designing these systems include technical issues associated with the complexity of air pollution and its science. These include inability to provide precise exposure concentrations or guidance on long-term/cumulative exposures or effects from pollutant combinations. Other issues relate to the degree to which people are aware and positively respond to these services. Looking to the future, mobile devices such as cellular phones, equipped with sensing applications have potential to provide dynamic, temporally and spatially precise exposure measures for the mass population. The ultimate aim should be to empower people to modify behaviour-for example, when to increase medication, the route/mode of transport taken to school or work or the appropriate time to pursue outdoor activities-in a way that protects their health as well as the quality of the air they breathe.
Mohan R, Walton HA, Thomson D, et al., 2012, The Buncefield Oil Depot Fire of 2005, Potential Air-Pollution Health Impacts Under Alternative Meteorological Scenarios, ISSN: 2157-3999
Objective: To model the possible air pollution-related health impact of the 2005 oil depot fire at Buncefield, near London, UK, under alternative meteorological conditions to those experienced at the time.Design: Atmospheric dispersion modelling of the smoke plume was conducted under the range of meteorological conditions occurring throughout 2005 assuming constant particle emission rates. Population exposure to particle concentrations (PM10) was calculated by linking the atmospheric dispersion modelling data (2 km resolution) and postcode population data. Health impacts were estimated using time-series-based exposure-response relationships for PM10 available from the epidemiological literature.Main outcomes: Estimates of pollution-related deaths brought forward, emergency hospital admissions from respiratory problems and emergency hospital admissions from cardiovascular disease. Findings: The highest four-day population exposure to PM10 for meteorological data from 2005 was predicted to occur between 5 and 8 August 2005, when northerly winds would have carried the plume towards London and surrounding areas of high population density. On these days, we estimated the additional PM10 exposure would have resulted in around 12 extra deaths brought forward, and around 13 additional emergency hospital admissions and a similar additional number of emergency admissions for cardiovascular disease. These numbers are slightly greater than estimated deaths and emergency admissions attributable to regular anthropogenic PM10 concentrations in south east England over the same four day period. Conclusions: Although the particle pollution-related health impacts of the Buncefield fire could have been higher under different meteorological conditions, it is unlikely that the impacts would be substantially greater than those attributable to regular anthropogenic particle pollution over the similar period. Keywords: oil depot fire; health impact; epidemiology; air pollution; explosion; a
Katsaiti I, Kelly F, Walton H, 2012, Quantification of the Antioxidant Depletion Capacity of Air Pollutants, Pages: S45-S46, ISSN: 0891-5849
Walton H, 2010, Development of proposals for cessation lag(s) for use in total impact calculations, The mortality effects of long-term exposure to particulate matter in the United Kingdom
Walton H, 2010, The Impact on Health of Emissions to Air from Municipal Waste Incinerators, Publisher: Health Protection Agency
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