Tests described in the following paragraph are designed to ensure resistance of EEEs to humid and polluted atmosphere. This kind of atmosphere generates mostly phenomena of atmospheric corrosion, electrolytic corrosion or electro-migration (adjacent metallic parts submitted to voltage difference), hydrolysis, swelling by absorption of water vapor … Besides, penetration of moisture within protected areas may be favored by thermal variations (breathing in tight cavities) as well as by cracking of tightness barriers (gaskets, joints, housings, resins …)..Chemical elements in this test originate from the action of the four main polluting elements in the automotive sector: ■ NaCl and CaCl2 (sodium chloride and calcium chloride). Those salts come from snow clearing products.■ SO2 and NO2 (sulfur dioxide and nitrogen dioxide): those two gaz come from fuel combustion.The aim of dry phases during those two tests is to allow restructuration of corrosion salts that may have been formed at the surface of unprotected metallic parts, and also desorption of water vapor that has been trapped within polymers