Development of a dual-collimation batch reactor for determining ultraviolet inactivation rate constants (k-values) for airborne microorganisms

We designed, constructed, and characterized a new dual-collimation UV air-phase reactor. This new system is unique because it collimates UV energy from a single lamp in two directions simultaneously. This dual-collimation feature provides two distinct advantages over traditional single-collimation systems: 1) real-time UV dose (fluence) determination because the radiometer sensor head remains in place during airborne microorganism exposure tests, and 2) simple actinometric determination of one overall correction factor (Reactor Factor = 0.39) that relates measured irradiance levels to actual irradiance levels experienced by the airborne microbes. This single correction factor replaces the four factors required for traditional collimated systems.