The indoor corrosion rates of copper, silver, nickel, cobalt, and iron were measured at eight locations in the United States. Concurrent pollutant and relative humidity measurements were also made at six sites. The rates are shown to be lognormally distributed over the sample population. A statistical comparison of outdoor and indoor rates shows that Ag corrodes approximately the same both indoors and outdoors. Cu and Ni corrode 100 times faster outdoors, and Fe corrodes 2000 times faster outdoors. The corrosion rate sensitivity to relative humidity is speculated to explain these differences. Pollutant concentrations are shown to be generally attenuated indoors except for NH₃ and reduced forms of sulfur. The indoor corrosion rates of copper and silver are reasonably well correlated to the measured reduced sulfur concentrations. Nickel rates correlate best to the acid chlorine containing gases.