Short-term Impact of Air Pollution on the Mortality. Results of the EMECAM Project in the Municipality of Madrid, 1992-1995

Abstract

Background: Despite the changes which have taken place in the sources of emissions, the levels of particles, SO2 and CO continue to be high in the municipality of Madrid. Apart from this, photochemical pollutants, such as NO2 and O3 are taking on growing importance due to the increased number of cars and trucks on the road and the major degrees of sunlight in this city. The objective of this article is to set out the short-term relationship between the major pollutants and the daily death rate in the city of Madrid for the 1992-1995 period, using the standardized procedure of the EMECAM Projects (Spanish Multicenter Study of Air Pollution and Death Rate). Methods: The daily fluctuations in the death rate for all causes except external ones for all ages and for those individuals over age 69 , in addition to those of the circulatory system and respiratory apparatus are related to the daily fluctuations in particles (PM10), SO2, NO2, CO and O3, by means of autoregressive Poisson regression models. The seasonality, tendency, temperature, relative humidity, flu, day of the week, holidays and events out of the ordinary are controlled. Results: Statistically significant positive relationships were found to exist between SO2 and all of the death rate series analyzed, between CO and the death rate of individuals over age 69, as well as with cardiovascular and respiratory deaths and of the particles to the death rate as the result of cardiovascular disease. A statistically significant relationship was also found to exist between NO2 and the cardiovascular death rate. These impact are immediate, that is to say, they occur with the pollutants of the same day. No significant positive relationships were found to exist for O3. Conclusions: These findings suggest that, for a broad spectrum of major pollutants, the current levels of air pollution in Madrid are related to a rise in the death rate.