Email updates

Keep up to date with the latest news and content from Environmental Health and BioMed Central.

Open Access Open Badges Research

Saharan dust and association between particulate matter and case-specific mortality: a case-crossover analysis in Madrid (Spain)

Julio Díaz1, Aurelio Tobías2* and Cristina Linares34

Author Affiliations

1 National School of Public Health, Carlos III Institute of Health. Avda.Monforte de Lemos, 5. 28029 Madrid, Spain

2 Institute of Environmental Assessment and Water Research (IDAEA), Spanish Council for Scientific Research (CSIC). C/JordiGirona, 18-26. 08034 Barcelona, Spain

3 Department of Environmental Epidemiology and Cancer, National Centre of Epidemiology, Instituto de Salud Carlos III, Madrid, Spain

4 CIBER Epidemiología y Salud Pública (CIBERESP), Madrid, Spain

For all author emails, please log on.

Environmental Health 2012, 11:11  doi:10.1186/1476-069X-11-11

Published: 8 March 2012



Saharan dust intrusions are a common phenomenon in the Madrid atmosphere, leading induce exceedances of the 50 μg/m3- EU 24 h standard for PM10.


We investigated the effects of exposure to PM10 between January 2003 and December 2005 in Madrid (Spain) on daily case-specific mortality; changes of effects between Saharan and non-Saharan dust days were assessed using a time-stratified case-crossover design.


Saharan dust affected 20% of days in the city of Madrid. Mean concentration of PM10 was higher during dust days (47.7 μg/m3) than non-dust days (31.4 μg/m3). The rise of mortality per 10 μg/m3 PM10 concentration were always largely for Saharan dust-days. When stratifying by season risks of PM10, at lag 1, during Saharan dust days were stronger for respiratory causes during cold season (IR% = 3.34% (95% CI: 0.36, 6.41) versus 2.87% (95% CI: 1.30, 4.47)) while for circulatory causes effects were stronger during warm season (IR% = 4.19% (95% CI: 1.34, 7.13) versus 2.65% (95% CI: 0.12, 5.23)). No effects were found for cerebrovascular causes.


We found evidence of strongest effects of particulate matter during Saharan dust days, providing a suggestion of effect modification, even though interaction terms were not statistically significant. Further investigation is needed to understand the mechanism by which Saharan dust increases mortality.