Human exposure to air contaminants under the far-UVC system operation in an office: effects of lamp position and ventilation condition DOI Creative Commons
Seongjun Park, Donghyun Rim

Scientific Reports, Journal Year: 2024, Volume and Issue: 14(1)

Published: Oct. 18, 2024

The far-UVC (222 nm) system has emerged as a solution for controlling airborne transmission, yet its effect on indoor air quality, particularly concerning positioning, remains understudied. In this study, we examined the impact of lamp position disinfection and secondary contaminant formation in small office. We employed three-dimensional computational fluid dynamics (CFD) model to integrate UV intensity fields formed by different positions (ceiling-mounted, wall-mounted, stand-alone types) along with quality model. Our findings reveal that ceiling-mounted type reduces human exposure pathogens up 80% compared scenarios without far-UVC. For all positions, O3 concentration breathing zone increases 4–6 ppb after one hour operation. However, it should be noted high (> 25 ppb) forms near when is turned on. Moreover, ventilation plays crucial role determining contaminants. Increasing rate from 0.7 h−1 4 pathogen concentrations 90%. caution warranted higher rates can lead elevated indoors, especially under conditions outdoor concentrations.

Language: Английский

Ozone Generation from a Germicidal Ultraviolet Lamp with Peak Emission at 222 nm DOI
Michael F. Link, Andrew Shore, Behrang H. Hamadani

et al.

Environmental Science & Technology Letters, Journal Year: 2023, Volume and Issue: 10(8), P. 675 - 679

Published: July 24, 2023

Recent interest in commercial devices containing germicidal ultraviolet lamps with a peak emission wavelength at 222 nm (GUV222) has focused on mitigating virus transmission indoors while posing minimum risk to human tissue. However, light can produce ozone (O3) air. O3 is an undesirable component of indoor air because health impacts from acute chronic exposure and its ability degrade quality through oxidation chemistry. In seven 4 h experiments, we measured the production single filtered GUV222 lamp 31.5 m3 stainless steel chamber. Using model, determined generation rate 19.4 ppbv h–1 ± 0.3 (equivalent 1.22 mg 0.02 h–1). We estimated fluence using two methods: (1) chemical actinometry tetrachloroethylene (actinometry) (2) geometric projection irradiance field radial angular distribution measurements (irradiance). rates 2.2 μW cm–2 3.2 (irradiance), predicted our chamber within 20% average mixing ratio. Future studies should evaluate technologies.

Language: Английский

Citations

29
Significant Production of Ozone from Germicidal UV Lights at 222 nm DOI Creative Commons
Zhe Peng, Douglas A. Day,

Guy A. Symonds

et al.

Environmental Science & Technology Letters, Journal Year: 2023, Volume and Issue: 10(8), P. 668 - 674

Published: July 28, 2023

Lamps emitting at 222 nm have attracted recent interest for germicidal ultraviolet disinfection ("GUV222"). Their impact on indoor air quality is considered negligible. In this study, ozone formation observed eight different lamps from five manufacturers, in amounts an order of magnitude larger than previous reports. Most produce O3 close to the first-principles calculation, with, e.g., a generation rate 22 ppb h–1 Ushio B1 modules 21 m3 chamber. Much more produced by when optical filters are removed tests and undesired internal electrical discharge. A test office shows increase ∼6.5 during lamp-on periods, consistent with simple model rate, ventilation, losses. We demonstrate use photolytic tracer (CBr4) quantify averaged GUV222 fluence room. An important consequence production particulate matter (PM) formation, which may significant negative health impacts. To limit GUV222-created pollution, new guidelines should be developed lower rates used if possible, especially under low-ventilation conditions. Low-cost sensors PM were not useful investigating GUV222-induced chemistry.

Language: Английский

Citations

29
Indoor Air Quality Implications of Germicidal 222 nm Light DOI Creative Commons
Victoria P. Barber, Matthew B. Goss,

Lesly J. Franco Deloya

et al.

Environmental Science & Technology, Journal Year: 2023, Volume and Issue: 57(42), P. 15990 - 15998

Published: Oct. 12, 2023

One strategy for mitigating the indoor transmission of airborne pathogens, including SARS-CoV-2 virus, is irradiation by germicidal UV light (GUV). A particularly promising approach 222 nm from KrCl excimer lamps (GUV

Language: Английский

Citations

29
Far-UVC disinfection of airborne and surface virus in indoor environments: Laboratory experiments and numerical simulations DOI

Kangqi Guo,

Yue Pan,

Hoi Fung Ronaldo Chan

et al.

Building and Environment, Journal Year: 2023, Volume and Issue: 245, P. 110900 - 110900

Published: Oct. 7, 2023

Language: Английский

Citations

18
Effects of 222 nm Germicidal Ultraviolet Light on Aerosol and VOC Formation from Limonene DOI Creative Commons
Olivia J. Jenks, Zhe Peng, Melinda K. Schueneman

et al.

ACS ES&T Air, Journal Year: 2024, Volume and Issue: 1(7), P. 725 - 733

Published: May 4, 2024

Since the 1930s, germicidal ultraviolet (GUV) irradiation has been used indoors to prevent transmission of airborne diseases, such as tuberculosis and measles. Recently, it received renewed attention due COVID-19 pandemic. While GUV radiation shown be effective in inactivating bacteria viruses, few studies on impact indoor air quality have published. In this work, we evaluate effects GUV222 (GUV at 222 nm) chemistry a common volatile organic compound (VOC), limonene. We found that production O3 by lamps caused formation particulate matter (PM) oxygenated compounds (VOCs). also proceeds through ozonolysis limonene well reaction with secondary OH, presence light led observable but small perturbations chemistry. Understanding is important evaluating safety these devices.

Language: Английский

Citations

7
Reducing Transmission of Airborne Respiratory Pathogens: A New Beginning as the COVID-19 Emergency Ends DOI Creative Commons
Linsey C. Marr, Jonathan M. Samet

Environmental Health Perspectives, Journal Year: 2024, Volume and Issue: 132(5)

Published: May 1, 2024

In response to the COVID-19 pandemic, new evidence-based strategies have emerged for reducing transmission of respiratory infections through management indoor air.

Language: Английский

Citations

6
Ozone generation and chemistry from 222 nm germicidal ultraviolet light in a fragrant restroom DOI
Michael F. Link,

Rileigh L. Robertson,

Andrew Shore

et al.

Environmental Science Processes & Impacts, Journal Year: 2024, Volume and Issue: 26(6), P. 1090 - 1106

Published: Jan. 1, 2024

Devices using 222 nm germicidal ultraviolet light (GUV222) have been marketed to reduce virus transmission indoors. However, GUV222 generates ozone which can react with gases and surfaces create undesirable air byproducts.

Language: Английский

Citations

6
Assessing the safety of new germicidal far‐UVC technologies DOI Open Access
Maximilian Görlitz, Lennart Justen, Patrick J. Rochette

et al.

Photochemistry and Photobiology, Journal Year: 2023, Volume and Issue: 100(3), P. 501 - 520

Published: Nov. 6, 2023

Abstract The COVID‐19 pandemic underscored the crucial importance of enhanced indoor air quality control measures to mitigate spread respiratory pathogens. Far‐UVC is a type germicidal ultraviolet technology, with wavelengths between 200 and 235 nm, that has emerged as highly promising approach for disinfection. Due its safety compared conventional 254 nm upper‐room systems, far‐UVC allows whole‐room direct exposure occupied spaces, potentially offering greater efficacy, since total room constantly treated. While current evidence supports using systems within existing guidelines, understanding upper limit critical maximizing effectiveness, particularly acute phase or epidemic when protection may be needed. This review article summarizes substantial present knowledge on regarding skin eye highlights research priorities discern maximum levels avoid adverse effects. We advocate comprehensive studies explore potential mechanisms harm, generate action spectra biological effects conduct high‐dose, long‐term trials. Such rigorous scientific investigation will key determining safe effective deployment in environments, contributing significantly future preparedness response.

Language: Английский

Citations

13
Comparison of effectiveness and energy use of airborne pathogen mitigation measures to meet clean air targets in a prototypical office building DOI
Cary A. Faulkner, Timothy I. Salsbury, Belal Abboushi

et al.

Building and Environment, Journal Year: 2024, Volume and Issue: 257, P. 111466 - 111466

Published: April 2, 2024

Language: Английский

Citations

4
Quantification of Byproduct Formation from Portable Air Cleaners Using a Proposed Standard Test Method DOI
Michael F. Link,

Rileigh Robertson,

Megan S. Claflin

et al.

Environmental Science & Technology, Journal Year: 2024, Volume and Issue: 58(18), P. 7916 - 7923

Published: April 29, 2024

In response to the COVID-19 pandemic, air cleaning technologies were promoted as useful tools for disinfecting public spaces and combating airborne pathogen transmission. However, no standard method exists assess potentially harmful byproduct formation from cleaners. Through a consensus development process, draft test portable cleaner performance was developed, suite of cleaners employing seven different tested. The quantifies not only removal efficiency challenge chemical ultrafine particulate matter but also formation. Clean delivery rates (CADRs) are used quantify particle efficiencies, an emission rate framework is formaldehyde, ozone, other volatile organic compounds. We find that tested photocatalytic oxidation germicidal ultraviolet light (GUV) produced highest levels aldehyde byproducts having 202 243 μg h

Language: Английский

Citations

4