This study looks at the weathering mechanism of glass exposed in a polluted environment. The weathering process implies both leaching by rain water and soiling. To follow the different steps of this weathering, a field experiment was performed in the centre of Paris. Samples of durable soda-lime-silica glass were exposed according to two conditions, sheltered and unsheltered from the rain. Samples were weighed before/after exposure and analysed by TOF-SIMS/ASEM. Results obtained show that leaching is of quite moderate extent. Soiling is the prevailing mechanism whatever the conditions of exposure. Soiling is caused by a progressive accumulation of calcium sulphate crystals on the sheltered glass and of "fresh" and "aged" microsoots on the unsheltered glass. Sulphates come from the evaporation of fog droplets & microsoots from anthropogenic emissions.
