In-Situ Filtration and Air Cleaning

JEFFREY SIEGEL, University of Toronto

     Abstract Number: 463
     Working Group: Reducing Aerosol Exposure with Control Technologies and Interventions

Abstract
Filtration and air cleaning standards (eg, ASHRAE Standard 52.2, AHAM AC-1, ISO 16890) allow for comparison of air cleaning approaches at standardized laboratory conditions. However, they have limited applicability to performance in actual buildings because of variations in air flow rates, filter efficiency changes, filter installation conditions, room volumes, air mixing, and background loss rates, among many other factors. As many of these factors vary over time over short time scales, the same filter will also often perform differently in the same environment over time. This presentation reports on different approaches to assess air cleaning in-situ with the goal of providing filtration and air cleaner users with actionable information on performance. Although the available methods differ in approach, instrumentation, data analysis, reference/placebo condition, and level of standardization – the results are consistent in demonstrating that the amount of relative (effectiveness) and absolute reduction in particle concentrations resulting from the use of any given air cleaning approach varies considerably over time and between environments. This presentation reports on data on 15 different air cleaners (including both room and central filters/air cleaners and those using various types of media as well as various electronic air cleaning approaches) in 10 different residential, commercial, and institutional environments. The overriding purposes are to provide evidence that in-situ testing is essential, provide a variety of approaches and considerations for conducting such testing, and illustrate the use of in-situ air cleaning results when benefits (health or otherwise) are being evaluated.