**2. Experimental area**

The region of Agadir, the district capital of Souss-Massa, is located on the southern Atlantic side of Morocco in the foothills of the Anti-Atlas. The area chosen for our investigations, is situated at the following geographical coordinates: 30°25<sup>0</sup> North, and 9°36<sup>0</sup> West. The type of dust targeted were collected from two sites in the plain of Souss-Massa, namely: the site of Adrar AD (30°25<sup>0</sup> 37.6″ N, 9°32<sup>0</sup> 24.1″ W) and the site of Halieutic-Park HP (30°24<sup>0</sup> 48.4″ N, 9°24<sup>0</sup> 04.5″ W) (**Figure 1**).

The meteorological data were acquired from a station located in Agadir, University IBN ZOHR, Department of Geology, for a period of 6 months from 24/02/2021 to 06/ 09/2021. The representative data of irradiance, and ambient temperature are shown in **Figure 2**.

Besides the interesting solar potential ranging from 0.8 to 1.2 kWh/m2 , the study area is hosting intensive industrial, touristic, and agricultural activities. Such activities are likely to contribute to the soiling of PV panels. In **Figure 2**, the average of temperature (green curves) in Agadir is respectively between 10°C and 45°C.
