Saharan dust and daily mortality in Emilia-Romagna (Italy)

Abstract

Objective To investigate the association between Saharan dust outbreaks and natural, cardiovascular and respiratory mortality. Methods A caseecrossover design was adopted to assess the effects of Saharan dust days (SDD) on mortality in the Emilia-Romagna region of Italy. The population under study consisted of residents in the six main towns of the central-western part of the region who died between August 2002 and December 2006. The association of Saharan dust outbreaks and PM 10 concentration with mortality was estimated using conditional logistic regression, adjusted for apparent temperature, holidays, summer population decrease, flu epidemic weeks and heat wave days. The role of the interaction term between PM 10 and SDD was analysed to test for effect modification induced by SDD on the PM 10 -mortality concentrationeresponse function. Separate estimates were undertaken for hot and cold seasons. Results We found some evidence of increased respiratory mortality for people aged 75 or older on SDD. Respiratory mortality increased by 22.0% (95% CI 4.0% to 43.1%) on the SDD in the whole year model and by 33.9% (8.4% to 65.4%) in the hot season model. Effects substantially attenuated for natural and cardiovascular mortality with ORs of 1.042 (95% CI 0.992 to 1.095) and 1.043 (95% CI 0.969 to 1.122), respectively. Conclusions Our findings suggest an association between respiratory mortality in the elderly and Saharan dust outbreaks. We found no evidence of an effect modification of dust events on the concentratione response relationship between PM 10 and daily deaths. Further work should be carried out to clarify the mechanism of action.

A Systematic Review of Global Desert Dust and Associated Human Health Effects

“…Three studies reporting the negative relationship for respiratory mortality are the same as those reporting the total mortality [19,20,22]. An exceptional study reported positive relationship for respiratory mortality but negative relationship for total mortality in Athens [21].…”

“…In general, long-distance transport reduces the number of heavier and larger particles in Saharan air masses, thus increasing the relative contribution of smaller particles. The results show that PM 2.5-10 (the usual definition of the coarse fraction adopted in air pollution monitoring and in epidemiological studies) should be employed with caution as a specific marker of Saharan dust transport, which is probably better described by PM 1-10 [22,67].…”

“…Ten of the published studies state that PM 10 particles present during dust days increase total mortality, while the other four studies find no association between mortality and PM 10 . Recently, Samoli et al [21] and Sajani et al [22] in Athens (Greece) and Emilia Romagna (Italy) found no evidence of any effect of dust events on the relationship between PM 10 and daily mortality. Similarly, two recent studies conducted in Kuwait and Taipei (Taiwan) also report stronger negative associations between PM 10 and all-cause mortality [19,20], supporting the viewpoint that desert dust comprising natural crustal materials is less toxic than that comprising anthropic particles.…”

Spatial and Temporal Variation of the Extreme Saharan Dust Event over Turkey in March 2016

“…Previous studies showed that dust originating from the Sahara is mainly transported to the Caribbean and South America [2,3], the Mediterranean and Europe [4], the eastern Mediterranean (EM hereafter), and the Middle East [5]. Due to the transfer of the Saharan dust to distant places of the world, numerous studies investigated its impacts on health problems (e.g., [6][7][8][9][10][11]), atmospheric heating and stability [12], cloud formation and radiation [13], and visibility [14], from regional perspectives. In the EM basin (extending from Turkey to northern Africa and eastward to Iran), dust loadings originating from Sahara are shown mostly in spring months [15] due to the occurrence of intense Sharav cyclones, which are generated by the thermal contrast between cold Atlantic air and warm continental air, over the south of the Atlas Mountains (Morocco).…”

African dust outbreaks over the Mediterranean Basin during 2001–2011: PM<sub>10</sub> concentrations, phenomenology and trends, and its relation with synoptic and mesoscale meteorology

“…Bearing in mind that African dust is an important source of particulate matter pollution in specific areas, causing by itself or contributing to exceed the daily limit values of PM 10 (in Europe being established in 50 µg m −3 by the 2008/50/EC Directive), and exerting negative health outcomes (Middleton et al, 2008;Mitsakou et al, 2008;Pérez et al, 2008;Jiménez et al, 2010;Mallone et al, 2011;Zauli Sajani et Samoli et al, 2011a, b;Tobías et al, 2011a, b), the identification of such episodes and the quantification of daily and annual contributions of desert dust to PM is currently necessary. Moreover, the identification of temporal trends in African dust contributions at ground-based monitoring sites may be indicative of atmospheric circulation changes.…”