Institutional Tuberculosis Transmission. Controlled Trial of Upper Room Ultraviolet Air Disinfection: A Basis for New Dosing Guidelines.

Rationale: Transmission is driving the global tuberculosis epidemic, especially in congregate settings. Worldwide, natural ventilation is the most common means of air disinfection, but it is inherently unreliable and of limited use in cold climates. Upper room germicidal ultraviolet (UV) air disinfection with air mixing has been shown to be highly effective, but improved evidence-based dosing guidelines are needed.

Characterizing ultraviolet germicidal irradiance luminaires.

In upper-room ultraviolet germicidal irradiance (UVGI) design, irradiance is an important characteristic, with two opposing dominant dynamics: high-level irradiation on the microorganism and minimum levels of irradiance on human skin and eyes. The use of high-level ray-tracing procedures is followed in establishing radiance and irradiance levels. The main constants in a room influencing these calculations are the spectral and spatial characteristics of the radiation sources in the inter-reflecting surfaces inside the luminaire, as well as the surfaces in the room.