ABSTRACT- PROJECT SUMMARY The research project will develop and evaluate methods for rapidly respirator-enabling many persons (surge response) and workers in small workplaces without access to occupational health experts. The work will compare three training methods (printed brochure, video, and computer-based). Factors determining respirator tolerance will be investigated. These include multi-domain subjective responses and physiologic factors such as respiratory pattern and work of breathing adjustment. The effect of personal factors such as health status and psychophysical respiratory load sensitivity will be investigated. The work will include methods to facilitate mask size selection (e.g., facial dimension) and the use of thermal imaging to identify facial sealing surface leakage. Quantitative fit testing, simulated work performance, and tolerance will be evaluated immediately after training and after six months. A diverse group of subjects will be recruited and will include English and Spanish speakers; elastomeric half facemask and filtering facepiece respirators will be used. The proposed cross sector research will build upon recent investigations and potentially lead to more effective respiratory protection programs.