Abstract

SAURINA, Carme; BARCELO, María Antònia; SAEZ, Marc  and  TOBIAS, Aureli. The short-term impact of air pollution on the mortality. Results of the EMECAM project in the city of Barcelona, 1991-1995. Rev. Esp. Salud Publica [online]. 1999, vol.73, n.2, pp.199-207. ISSN 2173-9110.

BACKGROUND: Most of the studies which demonstrate the existence of a short-term relationship between air pollution and morbidity and the death rate analyze the impact of "classic" pollutants which are by-products of combustion. However, the changes in the sources of these emissions, shifting basically toward road traffic, has made a change in air pollution, heightening the importance of the photochemical components, such as ozone (O₃) and nitrogen dioxide (NO₂). Barcelona is a city located in a mild climate zone, and its air pollution comes mainly from vehicle emissions. The main objective of this article is that of analyzing the relationship between the photochemical pollutants, NO₂ and O₃ and the death rate for different causes in the city of Barcelona throughout the 1991-1995 period, using the procedure for analysis set out as part of the EMECAM Project. METHODS: Daily changes in the number of deaths resulting from all causes, of the number of deaths for all causes of those over age 70, of the number of deaths resulting from circulatory system-related causes, and of the number of deaths resulting from respiratory-related causes are related to the daily changes in the photochemical pollutants using autoregressive Poisson models, controlling confusion-causing variables such as the temperature, the relative humidity, the systematic time structure and the autoregressive structure. RESULTS: Except for the relationship between O₃ and the death rate for causes involving respiratory illnesses, the relationships between photochemical pollutants and the death rate for all the causes considered were statistically significant. The risks related to dying as a result of rises in O₃ were greater than as a result of rises in NO₂, almost triple among circulatory system diseases. The risks related to dying for all the causes are lower than for specific causes and than for those individuals over age 70. The results of the analysis by six-month periods are quite similar to the overall results, revealing, in any event, relative risks somewhat greater during the warm months (May to October). CONCLUSIONS: Photochemical pollution, especially that which is caused by O₃, comprises a health risk. IN the case of NO₂, this might not be more than an indicators of the suspended particles or of other pollutants stemming from city traffic. There may be a certain adjustment between six-month periods of the impact of O₃ on the death rate for causes of the circulatory system.

Keywords : EMECAM Project; Mortality; Photochemical Pollution; Poisson Regression.

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