title: A combined analysis of the short-term effects of photochemical air pollutants on mortality within the EMECAM project.
abstract: In recent years, some epidemiologic studies have attributed adverse effects of air pollutants on health not only to particles and sulfur dioxide but also to photochemical air pollutants (nitrogen dioxide and ozone). The effects are usually small, leading to some inconsistencies in the results of the studies. Furthermore, the different methodologic approaches of the studies used has made it difficult to derive generic conclusions. We provide here a quantitative summary of the short-term effects of photochemical air pollutants on mortality in seven Spanish cities involved in the EMECAM project, using generalized additive models from analyses of single and multiple pollutants. Nitrogen dioxide and ozone data were provided by seven EMECAM cities (Barcelona, Gijón, Huelva, Madrid, Oviedo, Seville, and Valencia). Mortality indicators included daily total mortality from all causes excluding external causes, daily cardiovascular mortality, and daily respiratory mortality. Individual estimates, obtained from city-specific generalized additive Poisson autoregressive models, were combined by means of fixed effects models and, if significant heterogeneity among local estimates was found, also by random effects models. Significant positive associations were found between daily mortality (all causes and cardiovascular) and NO(2), once the rest of air pollutants were taken into account. A 10 microg/m(3) increase in the 24-hr average 1-day NO(2)level was associated with an increase in the daily number of deaths of 0.43% [95% confidence interval (CI), -0.003-0.86%] for all causes excluding external. In the case of significant relationships, relative risks for cause-specific mortality were nearly twice as much as that for total mortality for all the photochemical pollutants. Ozone was independently related only to cardiovascular daily mortality. No independent statistically significant relationship between photochemical air pollutants and respiratory mortality was found. The results in this study suggest that, given the present levels of photochemical pollutants, people living in Spanish cities are exposed to health risks derived from air pollution.
authors.affiliation: Research Group on Statistics, Applied Economics and Health (GRECS), Department of Economics, University of Girona, Campus de Montilivi, 17071 Girona, Spain. marc.saez@udg.es
authors.forename: Marc
authors.initials: M
authors.lastname: Saez
authors.forename: Ferran
authors.initials: F
authors.lastname: Ballester
authors.forename: Maria Antònia
authors.initials: MA
authors.lastname: Barceló
authors.forename: Santiago
authors.initials: S
authors.lastname: Pérez-Hoyos
authors.forename: Juan
authors.initials: J
authors.lastname: Bellido
authors.forename: José María
authors.initials: JM
authors.lastname: Tenías
authors.forename: Ricardo
authors.initials: R
authors.lastname: Ocaña
authors.forename: Adolfo
authors.initials: A
authors.lastname: Figueiras
authors.forename: Federico
authors.initials: F
authors.lastname: Arribas
authors.forename: Nuria
authors.initials: N
authors.lastname: Aragonés
authors.forename: Aurelio
authors.initials: A
authors.lastname: Tobías
authors.forename: Lluís
authors.initials: L
authors.lastname: Cirera
authors.forename: Alvaro
authors.initials: A
authors.lastname: Cañada
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000393:Air Pollutants / Q000009:adverse effects*; D002648:Child; D002675:Child, Preschool; D002947:Cities; D004781:Environmental Exposure; D016021:Epidemiologic Studies; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D009026:Mortality / Q000639:trends*; D009585:Nitrogen Dioxide / Q000009:adverse effects*; D010083:Oxidants, Photochemical / Q000009:adverse effects*; D010126:Ozone / Q000009:adverse effects*; D012044:Regression Analysis; D018570:Risk Assessment; D013030:Spain / Q000453:epidemiology
chemical_list: D000393:Air Pollutants; D010083:Oxidants, Photochemical; D010126:Ozone; D009585:Nitrogen Dioxide