Ozone Generation from a Germicidal Ultraviolet Lamp with Peak Emission at 222 nm

Environmental Science & Technology Letters, Год журнала: 2023, Номер 10(8), С. 675 - 679

Опубликована: Июль 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.

Язык: Английский

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

Building and Environment, Год журнала: 2023, Номер 245, С. 110900 - 110900

Опубликована: Окт. 7, 2023

Язык: Английский

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Effects of 222 nm Germicidal Ultraviolet Light on Aerosol and VOC Formation from Limonene

ACS ES&T Air, Год журнала: 2024, Номер 1(7), С. 725 - 733

Опубликована: Май 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.

Язык: Английский

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Reducing Transmission of Airborne Respiratory Pathogens: A New Beginning as the COVID-19 Emergency Ends

Environmental Health Perspectives, Год журнала: 2024, Номер 132(5)

Опубликована: Май 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.

Язык: Английский

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Ozone generation and chemistry from 222 nm germicidal ultraviolet light in a fragrant restroom

Environmental Science Processes & Impacts, Год журнала: 2024, Номер 26(6), С. 1090 - 1106

Опубликована: Янв. 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.

Язык: Английский

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Pentagon Found Daily, Metagenomic Detection of Novel Bioaerosol Threats to Be Cost-Prohibitive: Can Virtualization and AI Make It Cost-Effective?

Health Security, Год журнала: 2024, Номер 22(2), С. 108 - 129

Опубликована: Апрель 1, 2024

In 2022, the Pentagon Force Protection Agency found threat agnostic detection of novel bioaerosol threats to be "not feasible for daily operations" due cost reagents used metagenomics, sequencing instruments, and labor subject matter experts analyze bioinformatics. Similar operational difficulties might extend many 280,000 buildings (totaling 2.3 billion square feet) at 5,000 secure US Department Defense military sites, 250 Navy ships, as well civilian buildings. These economic barriers can still addressed in a manner by dynamically pooling samples from dry filter units, called spike-triggered virtualization, whereby depth are automatically modulated based on biothreats output. By running high average factor, annual per unit reduced 10 100 times depending chosen trigger thresholds. Artificial intelligence further enhance sensitivity virtualization. The risk infection during 12- 24-hour window between incident its remains, but some cases it 80% or more with high-speed indoor air cleaning exceeding 12 changes hour, which is similar rate passenger airplanes flight. That level hour higher likely cost-prohibitive using central heating ventilation conditioning systems, achieved economically portable filtration rooms typical ceiling heights (less than approximately $0.50 $1 foot do-it-yourself units $2 $5 high-efficiency particulate filters.

Язык: Английский

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Quantification of Byproduct Formation from Portable Air Cleaners Using a Proposed Standard Test Method

Environmental Science & Technology, Год журнала: 2024, Номер 58(18), С. 7916 - 7923

Опубликована: Апрель 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

Язык: Английский

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Formation and Transport of Secondary Contaminants Associated with Germicidal Ultraviolet Light Systems in an Occupied Classroom

Environmental Science & Technology, Год журнала: 2024, Номер 58(27), С. 12051 - 12061

Опубликована: Июнь 26, 2024

Germicidal ultraviolet light (GUV) systems are designed to control airborne pathogen transmission in buildings. However, it is important acknowledge that certain conditions and system configurations may lead GUV produce air contaminants including oxidants secondary organic aerosols (SOA). In this study, we modeled the formation dispersion of generated by operation employing C 254 222 nm. Using a three-dimensional computational fluid dynamics model, examined breathing zone concentrations chemical species an occupied classroom. Our findings indicate operating leads approximate increase 10 ppb O3 concentration 5.2 μg·m–3 SOA compared condition without operation, while increases about 1.2 μg·m–3, with minimal impact on concentration. Furthermore, increasing UV fluence rate from 1 5 μW·cm–2 results up 80% concentrations. For 254, elevating 30 50 or doubling radiating volume 50% Note indoor airflow patterns, particularly buoyancy-driven (or displacement ventilation), 15–45% lower well-mixed airflow. The also reveal when ventilation below 2 h–1, has smaller human exposure than 222. generate more at high levels (>15 ppb). These suggest design should consider room conditions.

Язык: Английский

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Formation of secondary aerosol by 222 nm Far-UVC irradiation on SO2

Atmospheric Environment, Год журнала: 2024, Номер 330, С. 120559 - 120559

Опубликована: Май 3, 2024

222 nm UV indoor disinfection using KrCl* excimer lamps has been gaining popularity due to claims of minimal ocular and skin damage from direct irradiation. However, the secondary aerosol formation under irradiation lamps, which could be an inhalation hazard, is less explored. SO2, a well-known precursor outdoor sulfate aerosol, also ubiquitous in environments urban cities northern China where coal used for domestic heating cooking. In this work, we studied by on Go: PAM flow reactor, scanning mobility particle sizer (SMPS), time-of-flight chemical composition monitor (ToF-ACSM). The nanoparticles was found much more effective at than 254 fluorescent lamp (FL) same doses RH, likely different SO2 oxidation mechanisms. We have that NH3 cooking volatile organic compounds (CVOC), as other indoor-relevant gases, promoted aerosols radiation SO2. Overall, can generate pollutants environments. Caution should taken during its application, especially areas with high concentrations such coal-fueled households.

Язык: Английский

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Influence of Germicidal UV (222 nm) Lamps on Ozone, Ultrafine Particles, and Volatile Organic Compounds in Indoor Office Spaces

Environmental Science & Technology, Год журнала: 2024, Номер 58(45), С. 20073 - 20080

Опубликована: Окт. 28, 2024

Germicidal ultraviolet lamps with a peak emission at 222 nm (GUV222) are gaining prominence as safe and effective solution to reduce disease transmission in occupied indoor environments. While previous studies have reported O

Язык: Английский

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