Conopco, Inc.

Unilever IP Holdings B.v.

Unilever Global IP Limited

Shangchun Yi

Sheng Meng

Yi Fang

Yajuan Li

Disclosed is a method of determining efficacy of a cosmetic composition to inhibit an atmospheric pollutant from contacting skin, comprising the steps of: (i) filling a sample holder of known dimensions with known amount of said composition to form a layer of defined thickness therein, where said sample holder is amenable to fluorescence-based assay; (ii) depositing, on said layer, a known amount of a model fine particulate matter which resembles an atmospheric pollutant at least in size and which comprises a material responsive to fluorescence microscopy which is excitable by a wavelength (&#x3bb;) and which emits radiation (&#x3bb;) where (&#x3bb;)&#x2260;(&#x3bb;); (iii) irradiating said composition and said model fine particulate matter by said &#x3bb;and recording intensity of fluorescence at &#x3bb;a plurality of times for a defined period during which said model fine particulate matter interacts with said layer; and, (iv) determining, corrected intensity of fluorescence at &#x3bb;by the following equation; corrected Intensity=recorded intensity/average transmittance where said average transmittance is the average of the transmittance of the composition measured at &#x3bb;and &#x3bb;determined by Beer-Lambert law by measuring the absorbance at &#x3bb;and &#x3bb;, where the corrected intensity is inversely proportional to said efficacy of said composition.

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Shanghai, China

Shangchun Yi