Atmospheric corrosion is a complex subject and, according to Fontana, accounts for more failures on a cost and tonnage basis than any other single environment. The degree of corrosion depends on the type of corrosive atmosphere (rural, marine, or industrial), temperature, and degree of moisture in the form of rain, dew, condensation or high humidity. Both galvanized steel and 304 stainless steel have been used successfully to protect against atmospheric corrosion. 304 stainless steel is generally more corrosion resistant than galvanized steel but it is also more costly. Selection of MOCs that will give satisfactory performance and longevity can only be done after detailed information regarding the specific environment (e.g. which pollutants are present) is compiled and analyzed.