Comparative evaluation of Spatio-Temporal Exposure Assessment Methods for estimating the health effects of air pollution (STEAM)

点击翻译按钮获取中文摘要

Background: Epidemiological studies have linked long- and short-term outdoor air pollution exposures to increased risks of death and morbidity. Cohort studies evaluate the health effects of long-term exposure by exploiting spatial heterogeneity in annual air pollution concentrations whereas time-series studies evaluate acute effects exploiting temporal variability in pollution concentrations. The extent to which the adverse health effects reported by these different study designs overlap has important implications for health impact assessment and policy development and to date this has not been investigated outside the US. In the past, both study designs have been limited by the availability of monitored pollution data but the development of dispersion and land use regression models have improved exposure assessment in cohort studies and enabled the investigation of a broader range of pollutants. The extension of these models to provide spatially resolved daily estimates of pollutant concentrations will enable an integrated assessment of health effects arising from both long- and short-term exposures to a wide range of pollutants and with applicability to locations with sparse or no monitoring.Objectives: 1.To develop, validate and compare dispersion, land use regression and satellite data based pollution models for London at both fine spatial (postcode level) and temporal (daily) scales. 2. To assess the performance of these methods and their combinations in estimating the health effects of long and short-term exposures to air pollutants. 3. To use the optimum integrated exposure method to estimate the relative importance of the effects of long-and short-term exposure for selected health outcomes. To achieve these objectives the project will use the expertise developed within the MRC-PHE Centre for Environment and Health and will need to draw upon the expertise of pioneering international groups (in the U.S. & Greece) in modelling, simulation studies and time series analyses.Methods: Models will be developed for particulate and gaseous pollutants and validated using measured concentrations from the London Air Quality Network. Their applicability to locations with sparse or no monitoring will be assessed using sequentially smaller parts of the available exposure information. An extensive simulation study, in which the "true" effect is known, will investigate the implications of using each exposure method on the health effect estimation (precision and bias).To enable proof of concept for the simultaneous estimation of long- and short-term effects on various health outcomes, the analysis of selected endpoints including GP consultations, hospital admissions and mortality data will be applied.Innovation aspects:1. Application of air pollution modelling approaches at a fine time and spatial resolution2. Integration of the different exposure assessment methods for optimizing their performance.3. Use of simulation methods to evaluate simultaneously the performance of models in assessing the effects of long- and short-term exposure to particulate and gaseous pollutants.4. Simultaneous estimation of health effects of long- and short-term exposure to air pollution in existing large health data sets to enable a comparison of their relative importance.Policy implications:1. Information on the advantages and disadvantages of each exposure model will inform the optimum extent and density of monitoring systems and other inputs to local models.2. The simultaneous estimation of the effects of short and long-term exposures will provide a rationale for the balance between emergency short-term action and long-term pollution management interventions.3. Informing the development of modelling in areas of Europe and the World where monitoring is not so dense.4. Informing health studies about the comparative importance of short vs long-term effects in areas of Europe and the World where health outcome data bases are limited