The Surface Project studied the microbial succession on office surfaces in nine offices in three North American cities. Building science parameters including relative humidity (RH), temperature, equilibrium relative humidity (ERH), illumination, and occupancy were measured to investigate their impact on microbial communities. Parameters were measured every five minutes over the course of a year. ERH, RH, temperature, occupancy, and illumination varied between offices, and cities which suggests that building characteristics and climate are important factors. RH, ERH, and temperature showed clear seasonal variation. The drywall ERH varied from ERH of ceiling tile and carpet and from the RH of air. Illumination was different in occupied and unoccupied offices. Occupancy did not cause that much difference in RH. Methodology analysis revealed no difference between different frequency measurements, although it is suggested that short-term intervals to be considered since long-term intervals may not show the large variation of building science parameters.M.A.S
