The Short-term Impact of Air Pollution on the Mortality. Results of the EMECAM Project in the city of Valencia, 1994-96

Abstract

Background: To determine the short-term impact of air pollution on the mortality in the city of Valencia throughout the 1994-1996 period by employing the Spanish multicenter study analysis method with regard to the relationship between air pollution and the death rate (EMECAM Project). Methods: The daily levels of black smoke, sulfur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO) and ozone (O3) were obtained from by the Valencia air pollution monitoring network. The deaths indicators analyzed were the daily number of deaths due to all causes, except the external ones, the death rate of those over age 70, and the deaths resulting from respiratory and cardiovascular diseases. Following the methods of the EMECAM Project, autoregressive Poison regression models were built up, controlling the different confunding factors (seasonality, trend, calendar, weather variables and flu impact). Results: For the totla mortality except the external ones, a significant impact of black smoke (RR 10 m g/m3: 1.013; CI95% 1.003 to 1.023) and for CO 24 h (RR 1 mg/m3: 1.024; CI95% 1.003 to 1.046) was found. For the mortality of those individuals over 70, the estimated impact was somewhat greater than for black smoke (RR 10 m g/m3: 1.017; CI95% 1.005 – 1.029), as well as for CO2 1h (RR 10 m g/m3: 1.007; CI95% 1.001 – 1.013). No significant relationship was found with the death rate due to respiratory or cardiovascular diseases for the entire period. Conclusions: The current levels of pollution in the city of Valencia show a significant impact on the daily mortality. These findings are consistent with the previous research and are coherent with those obtained on analyzing the relationship between air pollution and morbidity indicators.