Atmospheric corrosivity in Bogota as a very high-altitude metropolis questions international standards

This paper presents the first systematic atmospheric corrosion assessment in Bogota. Main facts about the study are related with special characteristics of the City, such as population (more than eight million inhabitants), and altitude (2600 m over the sea level). Relative humidity, temperature, and SO2 concentration were measured. Simultaneously, corrosion rate of AIS/SAE 1006 plain steel was measured along one year. Results show that atmospheric corrosion is between C₂ – C₃ levels, according to the ISO 9223 standard. Nevertheless, estimations from meteorological parameters produce lower corrosivities and, taking into account SO2 concentrations, corrosivities in places with higher relative humidity, are higher than corrosivities measured on steel coupons. In general, the main pollution problem is particulate matter, but higher corrosion rates were directly associated with SO2 levels. Gaps between found results and international estimation methodologies are evident. Some explanations about that, are proposed.