The effects of particulate matter (PM) sources on daily hospitalizations in three spanish cities, med-particles project

Abstract

Background: Many studies have reported associations between acute exposure to air pollution and hospitalizations, mainly for cardiovascular and respiratory causes. However, uncertainty remains about the specific sources that are responsible for these effects, particularly in Europe, where few studies on sources have been conducted. Also, Mediterranean cities have specific characteristics that influence air pollution composition, such as intense traffic, elevated sea emissions, intense solar radiation and high frequency of wildfires and Saharan dust episodes. This study assessed the association between various sources and daily hospitalizations in three Spanish cities within the framework of the MED-PARTICLES project. Methods: PM10 and PM2.5 concentrations were collected at regular intervals in three Spanish cities: twice a week from 2003-2010 in Barcelona, twice a week from 2007 to 2008 in Madrid and once a week from 2003 to 2010 in Huelva. Source apportionment using positive matrix factorization was developed for PM2.5. Case-crossover regression analysis was used to determine the independent effects of daily exposure to each factor on respiratory and cardiovascular hospitalization. Single-city estimates were combined using meta-analysis. Results: Three common different factors were identified for the three cities: "traffic" (interquartile range (IQR) 9.0 µg/m3), "minerals" (IQR 3.1 µg/m3) and "industrial" (only Barcelona and Huelva, IQR 1.7 µg/m3). The results indicate that traffic was associated with both respiratory (1.6% increase in hospitalizations per IQR increase, 95%CI 0.1-3.1) and cardiovascular hospitalizations at lag 3 (1.4%, 95%CI 0.0-2.4), and with respiratory hospitalization at lag 1 (1.8%, 95%CI 0.3-3.4). The results were homogeneous between the three cities (p>0.769). Conclusions: These results suggest that daily exposure to traffic contributes to the adverse health effects linked to PM2.5. Acknowledgements: MED-PARTICLES EU LIFE+ ENV/IT/327