Model for the Prediction of the Time of Wetness from Average Annual Data on Relative Air Humidity and Air Temperature

The data of the program designed by the Economic Commission for Europe of the United Nations Organization (UN ECE) to estimate the effect of air pollution on materials, including historical and cultural heritage, were used to study the relation between the time of wetness (TOW), temperature (T), and relative air humidity (Rh). The new relation resulting from the analysis allows one to predict TOW from average annual T and Rh. The relation is a conceptual and prognostic improvement of the previous ones describing TOW as functions of T and Rh. The parameters of the equation were determined from the data of the UN ECE program and verified with the use of ISOCORRAG/MICAT and Russian data in the temperature range from –16 to 28°C. The new relation allows TOW to be easily calculated, including classification purposes.