Disclosed is a method of determination of a pollution protection factor (PPF) of a cosmetic composition, comprising: (a) a step of testing, by any known test method, the ability (α) of the cosmetic composition to render ineffective at least one type of pollutant present on the skin and expressing it on a scale of 0 to 1, followed by calculating said PPF by equation A, where (1 - α) indicates corresponding potential residual damage to the skin wherein said composition comprises at least one ingredient known to render ineffective said at least one type of pollutant and said at least one ingredient is an anti-inflammatory or antioxidant； or alternatively, (b) a step of testing, by any known test method, the ability (β) of the cosmetic composition to inhibit the contact of at least one type of pollutant with skin and expressing it also on a scale of 0 to 1, followed by calculating said PPF by equation B, where (1 - β) indicates corresponding potential residual damage to the skin wherein said composition comprises at least one ingredient known to inhibit the contact of at least one type of pollutant with skin and wherein said ingredient is a sunscreen, a barrier enhancer or a polymer； or further alternatively, (c) a step of testing, by any known test method, the ability (γ) of the cosmetic composition to remove at least one type of pollutant present on the skin, expressing it also on a scale of 0 to 1, followed by calculating said PPF by equation C, where (1 - γ) indicates corresponding potential residual damage to the skin.L'invention concerne un procédé qui permet de déterminer le facteur de protection contre la pollution (PPF) d'une composition cosmétique, et qui comprend les étapes suivantes : (a) l'analyse, par n'importe quelle méthode d'analyse connue, de la capacité (α) de la composition cosmétique à rendre sans effet au moins un type de polluant présent sur la peau et son expression sur une échelle de 0 à 1, suivie du calcul dudit PPF par l'équation A, où (1 - α)
