Aerosol Science and Technology

VOLUME 30, NUMBER 2; FEBRUARY 1999

Development of a Method for Measuring Single-Pass Bioaerosol Removal Efficiencies of a Room Air Cleaner

Karin K. Foarde, James T. Hanley, David S. Ensor, and Peter Roessler

ABSTRACT

This paper presents the development of a method to measure single-pass microbial particle reduction by a room air cleaner having a built-in blower. The method used a Collison nebulizer to generate bioaerosol challenge for injection into a 14 m³/min air flow duct. Bioaerosol samplers (impactors) were used to obtain upstream and downstream samples. The success of the method required ensuring the survivability and culturability of the organisms, the selection of appropriate test organisms for this application, the implementation of the necessary control tests, the development of good sampling protocols, and the use of non-biological aerosol tests for comparisons and Quality Assurance / Quality Control (QA/QC) checks.

A series of filtration efficiency tests was performed on only the filter elements of the air cleaner. The tests were conducted with two Gram-positive bacteria, Bacillus subtilis and Staphylococcus epidermidis and, for comparison and QA/QC purposes, two non-biological challenge aerosols. The biological data compared well with the non-biological particulate test results and both results were highly reproducible. Next, a series of filtration efficiency tests was performed on the entire air cleaner assembly using five different biological aerosols (two bacteria, two fungi, and a virus). For these tests the air cleaner was mounted in a test duct with the built-in fan operating and the flows balanced to simulate free standing operation. The results of these tests were also highly repeatable and correlated well with the non-biological test results.

Return to the AS&T Table of Contents

Return to the AS&T Page

Return to the AAAR Home Page