Atmospheric corrosion plays a critical role in structural metal loss and thus infrastructure service life. Since the 1920's, many studies have focused on the effect of environmental parameters on the corrosion of major construction metals and it has been shown that chlorides, pollutants in the air such as sulfur dioxide, temperature, and relative humidity are the main environmental factors affecting the corrosion rate. Several studies have come up with a dose response function to predict the corrosion rate of a specific metal based on the environmental factors it is exposed to. The predicted corrosion rate is a critical design factor to secure safe and reliable infrastructure performance during its design service life. Therefore, future climatic changes in the environment may need to be considered when selecting a proper material and its required thickness as changes in environmental factors due to climate change in certain regions may affect the corrosion rates. Currently, historical data is used for designing infrastructures without considering the future climatic changes. This study summarizes the effort on atmospheric corrosion programs involving Canada's climate and illustrates the changes in corrosion rate of carbon steel in the City of Montreal over the past 70 years and up to 80 years in the future using the projections of climatic models. The goal is to demonstrate the effect of climate change and the variation in atmospheric exposure conditions for future durability designs of infrastructures such as bridges against atmospheric corrosion.
Structural steel, which is a critical component of many infrastructures, can suffer from deterioration of steel by reaction with air and its pollutants known as atmospheric corrosion when exposed to the environment. The risks associated with corrosion of newly-built and ageing infrastructure are high and their consequences costly. The recent International Measures of Prevention, Application, and Economics of Corrosion Technologies (IMPACT) study led by NACE International (now renamed as AMPP)  has shown for Canada the estimated annual corrosion cost to be $51.9 billion, which is 2.9 % of Canada's GDP. Engineers need to know the magnitude of atmospheric corrosion over time to design exposed structures safely and sustainably by adopting proper anti-corrosive protection measures or considering a more cautious material selection.