SAB4-PD-06 Introduction: The EMECAS project (Spanish Multicentric Study on the relationship between Air Pollution and Health) assesses the short-term effects of several pollutants on hospital admissions and mortality in Spain. Results for cardiovascular mortality are presented and compared with those for cardiovascular admissions. Methods: Fourteen cities, accounting for 9 million of inhabitants, participated. The study period ranged from 1993 to 1999. The daily number of deaths and emergency admissions for all cardiovascular diseases (ICD-9: 390–459) were obtained from the mortality register and hospital records, respectively. Black smoke (BS), total suspended particles (TSP), PM10, SO2, NO2, CO, and O3 data were provided by the regional air pollution networks. Using these data, daily indicators for each city were calculated: 24 hour average of BS, TSP, PM10, SO2, and NO2, 8 hours maximum moving average of CO and ozone, and 1 hour maximum of SO2, NO2, CO, and O3. The magnitude of association was estimated using generalized additive models (GAM) of Poisson controlling for confusion and overdispersion. Analyses were done using the S-Plus GAM function with stringent convergence criteria. Lagged effects up to 3 days were examined. For each cause and lag, combined estimates were obtained under a “random” or “fixed” effects model depending on if heterogeneity was present or not. Analyses for ozone were restricted to the warm period (May to October). Results: Local estimates were mostly positive. Lags 2 and 3 were the most consistent ones for CVS mortality, while for admissions lags 0 and 1 were the most consistent. Combined analyses showed an association with CVS mortality for 24-hour levels of BS, TSP, SO2, and NO2. An increase of 10 μg/m3 in BS levels was associated with a 1.13% (95 CI, 0.58%–1.67%) increase of the number of CVS deaths, the same increase in TSP was associated with a 0.98% (95 CI, 0.01%–1.97%) increase, NO2 with 0.44% (0.09%–0.80%) and SO2 with 1.4% (0.25%–2.5%). Weaker nonsignificant associations were found for 1-hour maximum indicators and neither ozone nor CO showed effect. For CVS admissions, estimates were in general of similar magnitude for 24-hour averages. Also 1-hour maximum indicators showed the same impact, and both ozone and CO showed effect. Discussion and Conclusions: An association between air pollution and cardiovascular health has been described in Spanish cities. In mortality, compared with hospital admissions, the effect was more delayed and daily peaks of pollutants showed no association. Study funded by the Spanish Ministry of Heatlh (FIS-FEDER 00/0010).