Acid deposition and the deterioration of stone: a brief review of a broad topic

The causes of stone deterioration due to acid deposition are examined, with specific reference made to important research on this subject from the past thirty years. The major topics covered include: dry deposition of atmospheric pollutants, the primary agent of acid deterioration of stone in urban areas; wet deposition, commonly referred to as acid rain; and major deterioration mechanisms. Key factors are dry deposition of gaseous pollutants such as SO 2 and NOx, the nature of the stone, including texture and porosity, and the presence of moisture on its surface as well as the ‘time of wetness’.