desiccators for 3 days prior to exposure. ASTM G 50-9715) standard was followed and the specimens were exposed to environment for 36 months (January 2009-Dec 2012). The exposure distance was 100 m from the marine and 200 m from the industrial environment. The topography map of the exposing the site is given in Fig. 1. The climatic and environmental parameters viz., relative humidity, temperature were obtained from Regional Meteorological Centre, Chennai. The amounts of atmospheric deposition of Cl¹ and SO2 content in the field were estimated using wet candle and sulphonation plate procedures prescribed in ASTM G 140-9616) and ASTM G 91-9717) were followed. The 3 years average environmental parameters are listed in Table 2.