PROBLEMS AND SOLUTION

Atmospheric pollution can attack stone structures and monuments at an accelerating rate. Pollution from fossil fuel by-products, together with airborne particles, form a black encrustation which is evidenced on a variety of stone substrates.

Removal of built-up pollution can be challenging without

damaging the underlying stone substrate, which may be softer or soluble than a layer of pollution. Conventional cleaning, which is typically carried out with micro-abrasives, chemicals, solvents, swabs or electrolysis, can cause permanent damage to many surfaces. Current laser cleaning techniques take advantage of the most recent advanced high-intensity light of a laser source for cleaning of the surface and its treatment. The laser cleaning procedure has been successfully extended in the cleaning of other substrates like wood, leather, paper, metals and ceramic. As the surface is cleaned using a parameter of carefully adjusted light intensities and rates of cleaning, surfaces are cleaned using the gentlest means possible. Laser cleaning is non-contact, versatile and can be safely used on delicate surfaces.