Air Filtration of Microbial Particles

Abstract

Air filtration is an efficient means of removing microbial particles from air. Various types of filters have been evaluated using, as a test simulant, Bacillus subtilis var niger spores aerosolized in particles with diameters of 1 to 5[mu]. Based on results of these tests, filters were placed in 4 categories roughing, medium, high, and ultra-high efficiency. Particle-removal efficiency of an entire filter system can easily reach 95%, a level considered satisfactory for most situations, and can achieve 99.99+ % when necessary. Other air cleaners, including washers, electrostatic precipitators, and UV devices, generally have not provided consistently high levels of removal efficiency under field conditions.