AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
PM2.5 Loading Characteristics of Commercial Indoor Electret HVAC and Air Cleaner Filter Media
MIN TANG, Sheng-Chieh Chen, De-Qiang Chang, David Y. H. Pui, South China University of Technology,University of Minnesota
Abstract Number: 381 Working Group: Control Technology
Abstract Particulate matter, PM, a major component of outdoor air pollution, has been classified as carcinogenic to humans in October of 2013 by the World Health Organization specialized cancer agency, the International Agency for Research on Cancer, IARC. Noticeably, PM2.5 contributes the essential toxicity of ambient PM, which not only can easily infiltrate into indoor environment but also get into deeper human lung. China and its sounding countries, Korea and Japan are frequently hit by high PM2.5 pollutions and filtration techniques such as indoor air cleaners and central HVAC systems are more and more widely applied to mitigate the human exposure. In these equipment, electret filter media are used but the existing test standard, ASHRAE 52.2-2012, only challenges the filter with particles larger than 300 nm. Therefore it's urgent to challenge these electret media with PM2.5 and nanoparticles to get a more accurate performance of these media against the existing smaller indoor particles.
In this work, penetrations of commercial electret media used in HVAC and air cleaners against simulated PM2.5 down to 3 nm were tested along different loading mass of PM2.5. Results show that the electrostatic effect is more significant for particles larger than 20 nm. In comparison, the mechanical diffusion deposition plays an important role for nanoparticles smaller than 20 nm. The PM2.5 holding capacity varies significantly with the mass concentration of the PM2.5 in the feed. The lower PM2.5 concentration results in a higher PM2.5 holding capacity, which is expected to be associated with the collapse and formation dynamics of the particle dendrite. For acquiring a more realistic loading characteristic for the widely used electret media, it is recommended that the test method in ASHRAE 52.2-2012 might be modified.