Aerosol Science: Technology and Applications

Chapter 17

Disinfection of Airborne Organisms by Ultraviolet-C Radiation and Sunlight

Jana S. Kesavan and Jose-Luis Sagripanti

Edgewood Chemical Biological Center, Aberdeen Proving Ground, USA

17.1 Introduction

Bioaerosols are a serious concern to human health because of their potential role in the transmission of infectious diseases during natural epidemics or after intentional release of biological agents through acts of terrorism or warfare. Extensive research has been conducted toward understanding the disinfection of organisms deposited on surfaces, suspended in water, and contaminating food, all of which have been discussed elsewhere (Block, 2001). In contrast, the disinfection of microorganisms in aerosols has received much less attention, mainly because of the difficulties inherent in conducting the experiments. Airborne organisms are difficult to reach with the liquid disinfectants that are commonly used to treat medical devices, foods, and drinking water. Therefore, the primary means of organism inactivation in aerosols is ultraviolet (UV) radiation.

Radiation from sunlight is used as a disinfectant to kill organisms. Radiation of <290 nm wavelength is absorbed by atmospheric ozone before sunlight reaches the earth's surface; therefore, the longer UV wavelengths in sunlight provide the main germicidal agent in the environment (Jagger, 1985; Giese, 1976; Lytle and Sagripanti, 2005). Germicidal UV lights are relatively easy to use indoors; hence, light with 254 nm wavelength ...