CHAPTER 3
 ASSESSMENT OF IODINE-TREATED FILTER MEDIA FOR REMOVAL AND
 INACTIVATION OF MS2 BACTERIOPHAGE AEROSOLS

 Objective

 The objective of the study in this chapter was to evaluate an iodine-treated filter medium

for removal and inactivation of viral aerosols under various environmental conditions and

explore inactivation mechanisms of the filter. Physical removal efficiency (PRE), viable

removal efficiency (VRE), pressure drop, 12 concentration in the impinger medium, and the

infectivity of viruses collected on the iodine-treated filter were investigated and compared with

those of an untreated filter. The inactivation mechanism proposed earlier for the iodine-treated

filter was examined by measuring VRE downstream of the filter using various collection media

that were inert, moderately reactive and aggressively reactive to 12. Furthermore, a second

possible source of inactivation mechanisms was considered-I2 released from the filter and

transported to the impinger where the inactivation was hypothesized to occur.

 Materials and Methods

Test Filters

 Samples of the iodine-treated (polyester-cotton, 125 g/m2 triiodide resin, Safe Life Corp.,

San Diego, CA, USA) and untreated (polyester-cotton, Safe Life Corp., San Diego, CA, USA)

filter media, both as flat sheets 1 mm thick, were tested as discs of 47- mm diameter. The

information on the preparation of an iodine-treated filter is described in Chapter 2. The I2

concentration was measured to be 0.004 mg I2/m3

Test Microorganisms

 MS2 bacteriophage (ATCC 15597-B1TM) was selected as a representative virus aerosol.

In the selection of a model virus, its resistance to antimicrobial agents should be considered

because resistance varies from one virus to another (Berg et al. 1964; Sobsey et al. 1990). MS2