Self cleaning versus float glass in urban atmosphere

In order to test the self cleaning efficiency of self cleaning glass, a field experiment was conducted in Paris, at a site with representative background urban pollution. Hydrophilic photocatalytic TiO₂ coated glasses and a traditional float glass (reference) were exposed in sheltered and unsheltered conditions, for various time durations. In parallel, air sampling was carried out in order to assess the chemical compositions of airborne particulates. Analytical measurements were performed on the aerosols and on the deposits that occurred on the glasses. The analyses involved the determination of the organic fraction (organic carbon, particulate organic matter, water soluble organic carbon), elemental carbon and soluble inorganic fractions. The impairment of the optical properties of the glass was followed via haze measurements. Based on this field exposure, the efficiency of the self cleaning glass was highlighted, in particular there was an important decrease of the organic fraction measured on TiO₂ coated glasses as compared to the reference glass.