Short-term effects of PM10 from Saharan dust on mortality in Southern Europe - Results of the MED-PARTICLES Project

摘要

Background. Enhanced short-term effects of particulate matter (PM) on mortality during desert dust outbreaks have been shown, with controversial results. Aim.To estimate the short-term effects of PM from Saharan dust on mortality in multiple Euro-Mediterranean cities, within the MED-PARTICLES project. Methods. Daily counts of cause-specific deaths were collected for 12 cities from Italy, Spain, Greece and France within 2001-2010. Data were available on daily mean concentrations of PM10 (PM＜10 μm), PM2.5 (＜2.5μm), PM2.5-10 (PM between 2.5 and 10 μm). Saharan dust episodes were identified using satellite data, operational models and back-trajectories. Daily PM10 concentrations attributable to Sahara were estimated from PM10 observations monitored at rural stations. PM10 from local sources was derived as the difference between total and Saharan PM10. City-specific Poisson regression models were fit, followed by random-effects meta-analysis. Results.The frequency of Saharan dust days ranged between 33% in Southern Greece and 13% in Northern Italy, with highest dust load in the Eastern Mediterranean basin (17 μg/m3 in Athens). Overall, all PM metrics were strongly associated with natural, cardiovascular and respiratory mortality, but no clear effect modification of Saharan dust outbreaks was detected, with high heterogeneity across cities. In contrast, on Saharan dust days, 10 μg/m3 increases in Saharan PM10, lag 0-5, were associated with 5.88% (95% confidence interval: 0.20,11.88) increased respiratory mortality, with no heterogeneity across cities,while no effect was found for PM10 from local sources (-0.42%; 95% CI: -8.14, 7.95) on Saharan days. Conclusions. We found evidence of effect modification of Saharan dust on PM10-mortality association only in a few cities. A strong homogeneous effect of PM10 from Sahara was found on respiratory mortality. On-going analyses deal to disentangle the effects of Saharan and local sources of PM10 and the heterogeneity of effects. Acknowledgements: MED-PARTICLES EU LIFE10 ENV/IT/327.