ASTHMA, URBAN ATMOSPHERIC-POLLUTION AND THE WEATHER

The aim of this study, which was carried out in an urban environment, was to research in to a possible relationship between temporal variati ons in the level of atmospheric pollution in the centre of Paris, comp ared to the frequency of acute dyspnoeic crises in which asthmatic pat ients had requested the emergency service (SOS Medecins). This study b egan in the first half of 1989; during this period there were 701 case s of acute asthma recorded within the Paris city boundary by << SOS Me decins >>. The pollutants recorded were sulphur dioxide (SO2), an inde x of black smoke (FN), oxides of nitrogen (NOx), ozone (O3) and solubl e sulphate particles (SO4). In addition, the weather patterns were exa mined and pollen counts were recorded. In spite of a sub-acute episode of pollution in January and February, there was no definite increase noted in the number of emergency calls made for acute asthma. In the f irst three months, the number of crises were, on average, higher in as sociation with high levels of the principal pollutants (SO2 FN, NOx, S O4) as well as with the periods of high atmospheric pressure; however, only the sulphate content and atmospheric pressure remained correlate d with the daily number of asthmatic crises. In the second three month s, there were some co-variations uniquely associated with sulphate par ticles, the atmospheric pressure, and above all the ozone level (allow ing for a gap of one day). The influence of the daily variations in to tal pollen content or of grass pollens did not show up in this study.