Casablanca is the biggest city of Morocco with more than 4 millions inhabitants. It is also the most industrialised city with more than 45% of all the national industrial and economic activity; And its automobile parc is the most numerous with more than 50 % of all the national parc. As a consequence and for other reasons the city has been supposed to be among the most polluted cities in the region. In order to evaluate this pollution a campaign has been undertook. In other words, the campaign has two objectives:

§ To know which pollutants concentrations pass frequently the norms; § To know which regions of the city are the frequently subject to high levels of pollution.

For this, a mobile laboratory has been used. It is a mobile vehicle equipped with a set of electronic instruments to measure, in addition to meteorological parameters, CO, SO2, NOx, O3, VOC, lead and cadmium in dust. Each year, four sites has been sampled once each season. The sampling duration per site and per season is 22 days. The whole campaign duration is two years. This manner to prospect has been dictated by the fact that air pollution concentrations depend on meteorological parameters which depend, themselves, on the season.

The four sites has been chosen with the intent to sample a residential site, an industrial site, a site with a considerable automobile trafic, and a site which combines the first two qualities.

The poster presents the results of the campaign and the warning system which is being installed in the city. The warning system began with two stations and will be extended as often as possible.