Many materials that may seem suitable for storage or display purposes can cause serious damage to museum collections. They can cause corrosion, discolouration or deterioration of objects, either because they give off harmful vapours or because they are in direct contact with the museum object. These processes of corrosion, discolouration and deterioration are speeded up by high temperature and/or high humidity levels.
Harmful volatile substances include formaldehyde, acetic acid, formic acid, sulphuric acid, sulphur dioxide, nitrogen dioxide, ozone, and ammonia gas.
Sources of these substances include wood products, acrylic resins, paints, lacquers and varnishes, glues and adhesives, pesticides, insecticides, fungicides, furnishing fabrics, adhesive tape and other sticky materials such as “Plasticine” and “Blu-tack”. Electrical machinery such as electrostatic air cleaners and some photocopying machines may produce ozone. Burning fossil fuels can produce harmful vapours and air-borne soot particles.