ATMOSPHERIC-POLLUTION BY AIRBORNE MICROORGANISMS IN THE CITY OF MARSEILLES

Outdoor airborne microflora was investigated in urban and natural area s, the city of Marseilles and the natural reserve of Porquerolles Isla nd, respectively. In Marseilles, concentrations of airborne viable mic roorganisms averaged 791 +/- 598 bacteria m(-3) (with a geometric mean of 536 +/- 103 bacteria m(-3)) and 92 +/- 92 fungi m(-3) (with a geom etric mean of 63 +/- 15 fungi m(-3)). In Porquerolles Island, concentr ations of airborne microorganisms reached 42 +/- 70 bacteria m(-3) (wi th a geometric mean of 26 +/- 7 bacteria m(-3)) and 46 + 55 fungi m(-3 ) (with a geometric mean of 33 +/- 8 fungi m(-3)). Airborne microflora , which followed a log-normal distribution in Marseilles, was shown to have a large variability. Airborne bacteria increased with temperatur e and wind velocity whereas airborne fungi increased with temperature and varied with wind direction in urban and natural areas. Partial ide ntification of bacteria in Marseilles and Porquerolles Island showed t hat geographical location had qualitative as well as quantitative infl uence on airborne microflora, this was illustrated by an increase of g lobal airborne microorganisms, and more particularly Gram negative bac teria, in the urban area.