Short-term effects of desert and non-desert PM 10 on mortality in Sicily, Italy.

Background: Increased PM ₁₀ concentrations are commonly observed during Saharan dust advections. Limited epidemiological evidence suggests that PM ₁₀ from anthropogenic and desert sources increase mortality. We aimed to evaluate the association between source-specific PM ₁₀ (non-desert and desert) and cause-specific mortality in Sicily during 2006-2012 period.
Methods: Daily PM ₁₀ concentrations at 1-km ² were estimated in Sicily using satellite-based data, fixed monitors and land use variables. We identified Saharan dust episodes using meteorological models, back-trajectories, aerosol maps, and satellite images. For each dust day, we estimated desert and non-desert PM ₁₀ concentrations. We applied a time-series approach on 390 municipalities of Sicily to estimate the association between PM ₁₀ (non-desert and desert) and daily cause-specific mortality.
Results: 33% of all days were affected by Saharan dust advections. PM ₁₀ concentrations were 8 μg/m ³ higher during dust days compared to other days. We found positive associations of both non-desert and desert PM ₁₀ with cause-specific mortality. We estimated percent increases of risk (IR%) of non-accidental mortality equal to 2.3% (95% Confidence Interval [CI]: 1.4, 3.1) and 3.8% (3.2, 4.4), per 10 μg/m ³ increases in non-desert and desert PM ₁₀ at lag 0-5, respectively. We also observed significant associations with cardiovascular (2.4% [1.3, 3.4] and 4.5% [3.8, 5.3]) and respiratory mortality (8.1% [6.8, 9.5], and 6.3% [5.4, 7.2]). We estimated higher effects during April-September, with IR% = 4.4% (3.2, 5.7) and 6.3% (5.4, 7.2) for non-desert and desert PM ₁₀ , respectively.
Conclusions: Our results confirm previous evidence of harmful effects of desert PM ₁₀ on non-accidental and cardio-respiratory mortality, especially during the warm season.
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