Investigation of Weeping Glass Deterioration Under Controlled Relative Humidity Conditions

Whilst research has been published on the impact of pollution on glass, there is no consensus on the risk from formaldehyde. A controlled relative humidity (RH) showcase used with visually weeping glass was studied. At under 42% RH, the presence of formaldehyde and formic acid continue to produce sodium formate salts on the glass surface. Estimates of the glass deterioration rate have been made. The likely occurrence of a Canizzaro type reaction was elucidated by the formation of methanol in both laboratory and field measurements.