Short-term exposure to traffic-related air pollution and daily mortality in London, UK.

Richard W Atkinson,Antonis Analitis,Hugh R Anderson,Gary W Fuller,David C Green,Frank J Kelly,Evangelia Samoli,Ian S Mudway

doi:10.1038/jes.2015.65

Abstract

Epidemiological studies have linked daily concentrations of urban air pollution to mortality, but few have investigated specific traffic sources that can inform abatement policies. We assembled a database of >100 daily, measured and modelled pollutant concentrations characterizing air pollution in London between 2011 and 2012. Based on the analyses of temporal patterns and correlations between the metrics, knowledge of local emission sources and reference to the existing literature, we selected, a priori, markers of traffic pollution: oxides of nitrogen (general traffic); elemental and black carbon (EC/BC) (diesel exhaust); carbon monoxide (petrol exhaust); copper (tyre), zinc (brake) and aluminium (mineral dust). Poisson regression accounting for seasonality and meteorology was used to estimate the percentage change in risk of death associated with an interquartile increment of each pollutant. Associations were generally small with confidence intervals that spanned 0% and tended to be negative for cardiovascular mortality and positive for respiratory mortality. The strongest positive associations were for EC and BC adjusted for particle mass and respiratory mortality, 2.66% (95% confidence interval: 0.11, 5.28) and 2.72% (0.09, 5.42) per 0.8 and 1.0 μg/m3, respectively. These associations were robust to adjustment for other traffic metrics and regional pollutants, suggesting a degree of specificity with respiratory mortality and diesel exhaust containing EC/BC.

Highlights

Epidemiological studies have provided a substantial body of evidence linking daily concentrations of outdoor air pollution to adverse effects on a range of health outcomes
We investigated associations between daily concentrations of specific traffic-related pollutants and daily total and cause-specific mortality in London between 2011 and 2012
Associations with respiratory mortality were generally positive, stronger in the warmer months of the year and most convincing for elemental carbon (EC) and black carbon (BC) adjusted for particulate matter (PM) mass

Summary

Introduction

Epidemiological studies have provided a substantial body of evidence linking daily concentrations of outdoor air pollution to adverse effects on a range of health outcomes. Time-series studies investigating associations between trafficrelated pollution and mortality have used source-apportioned exposures to traffic[15,16,17,18,19] or routinely measured pollutants such as PM2.5 or nitrogen dioxide (NO2)[5] or elemental (EC) or black carbon (BC).[13] There is suggestive evidence for the biological mechanism of these effects from controlled toxicological exposure studies,[20] with increases in markers of oxidative stress[21] and evidence of DNA methylation changes identified.[22] Because some trafficrelated pollutants have other sources and spatial distributions, the challenge is to identify the degree to which the various components are specific for traffic, both in the near-roadside and urban background context To meet this challenge, extensive data monitoring networks and measurement campaigns providing complete daily data over a sufficiently long period of time are required. Few epidemiological studies have been able to fully assess health effects associated with specific sources

Methods

Results

Conclusion