Short-term relationships between urban atmospheric pollution and respiratory mortality: time series studies

Time series studies conducted in the field of air pollution aim at testing and quantifying short-term relations which can exist between daily air poll ution levels and daily health effects. The method used for this type of sun ,ey has sometimes been misunderstood mainly because individual factors and indoor exposure to air pollutants were not taken into account. The adjustme nt on these individual confounding factors commonly used in classic epidemi ologic studies (case-control studies, cohort studies) is not adequate to ti mes sen. es studies which are based on aggregate data. This is different fo r those factors that change over it. me according to the levels of air poll ution (meteorological conditions, influenza epidemics, trend of health case s) which, when being analysed, must be taken into account either indirectly through time modelling or directly through non-linear modelling processes. During this last decade, numerous studies using the time series method hav e been published and have found short-term associations between daily level s of air pollution commonly observed and daily respiratory, mortality. The consistency of the numerous results published in the international literatu re are more arguments in favour of non-confounding short-term relations bet ween air pollution and respiratory mortality.