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Large-scale evaluation of microorganism inactivation by bipolar ionization and photocatalytic devices.

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Title: Large-scale evaluation of microorganism inactivation by bipolar ionization and photocatalytic devices.
Authors: Ratliff, Katherine M.1 (AUTHOR) Ratliff.Katherine@epa.gov, Oudejans, Lukas1 (AUTHOR), Archer, John1 (AUTHOR), Calfee, Worth1 (AUTHOR), Gilberry, Jerome U.2 (AUTHOR), Hook, David Adam2 (AUTHOR), Schoppman, William E.2 (AUTHOR), Yaga, Robert W.2 (AUTHOR), Brooks, Lance1 (AUTHOR), Ryan, Shawn1 (AUTHOR)
Source: Building & Environment. Jan2023:Part 1, Vol. 227, pN.PAG-N.PAG. 1p.
Subject Terms: Microbial inactivation, Airborne infection, Technological innovations, Photoreduction, Microbiological aerosols
Abstract: The COVID-19 pandemic has raised awareness in the spread of disease via airborne transmission. As a result, there has been increasing interest in technologies that claim to reduce concentrations of airborne pathogens in indoor environments. The efficacy of many of these emerging technologies is not fully understood, and the testing that has been done is often conducted at a small scale and not representative of applied settings. There is currently no standard test method for evaluating air treatment technologies, making it difficult to compare results across studies or technology types. Here, a consistent testing approach in an operational-scale test chamber with a mock recirculating heating, ventilation, and air conditioning (HVAC) system was used to evaluate the efficacy of bipolar ionization and photocatalytic devices against the non-enveloped bacteriophage MS2 in the air and on surfaces. Statistically significant differences between replicate sets of technology tests and control tests (without technologies active) are apparent after 1 h, ranging to a maximum of 0.88 log 10 reduction for the bipolar ionization tests and 1.8 log 10 reduction for the photocatalytic device tests. It should be noted that ozone concentrations were elevated above background concentrations in the test chamber during the photocatalytic device testing. No significant differences were observed between control and technology tests in terms of the amount of MS2 deposited or inactivated on surfaces during testing. A standardized, large-scale testing approach, with replicate testing and time-matched control conditions, is necessary for contextualizing laboratory efficacy results, translating them to real-world conditions, and for facilitating technology comparisons. • Large-scale testing useful for evaluating technology efficacy against bioaerosols. • Time-matched control tests (no technology active) critical for assessing efficacy. • Replicate experiments at each condition essential for characterizing efficacy. • Devices can demonstrate marginal benefit that generally increases with time. • Elevated ozone concentrations observed in photocatalytic device experiments. [ABSTRACT FROM AUTHOR]
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Database: GreenFILE
Description
Abstract:The COVID-19 pandemic has raised awareness in the spread of disease via airborne transmission. As a result, there has been increasing interest in technologies that claim to reduce concentrations of airborne pathogens in indoor environments. The efficacy of many of these emerging technologies is not fully understood, and the testing that has been done is often conducted at a small scale and not representative of applied settings. There is currently no standard test method for evaluating air treatment technologies, making it difficult to compare results across studies or technology types. Here, a consistent testing approach in an operational-scale test chamber with a mock recirculating heating, ventilation, and air conditioning (HVAC) system was used to evaluate the efficacy of bipolar ionization and photocatalytic devices against the non-enveloped bacteriophage MS2 in the air and on surfaces. Statistically significant differences between replicate sets of technology tests and control tests (without technologies active) are apparent after 1 h, ranging to a maximum of 0.88 log 10 reduction for the bipolar ionization tests and 1.8 log 10 reduction for the photocatalytic device tests. It should be noted that ozone concentrations were elevated above background concentrations in the test chamber during the photocatalytic device testing. No significant differences were observed between control and technology tests in terms of the amount of MS2 deposited or inactivated on surfaces during testing. A standardized, large-scale testing approach, with replicate testing and time-matched control conditions, is necessary for contextualizing laboratory efficacy results, translating them to real-world conditions, and for facilitating technology comparisons. • Large-scale testing useful for evaluating technology efficacy against bioaerosols. • Time-matched control tests (no technology active) critical for assessing efficacy. • Replicate experiments at each condition essential for characterizing efficacy. • Devices can demonstrate marginal benefit that generally increases with time. • Elevated ozone concentrations observed in photocatalytic device experiments. [ABSTRACT FROM AUTHOR]
ISSN:03601323
DOI:10.1016/j.buildenv.2022.109804