Indoor Air Quality Implications of Germicidal 222 nm Light

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

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The persistence of smoke VOCs indoors: Partitioning, surface cleaning, and air cleaning in a smoke-contaminated house

Science Advances, Journal Year: 2023, Volume and Issue: 9(41)

Published: Oct. 13, 2023

Wildfires are increasing in frequency, raising concerns that smoke can permeate indoor environments and expose people to chemical air contaminants. To study transformations evaluate mitigation strategies, we added a test house. Many volatile organic compounds (VOCs) persisted days following the injection, providing longer-term exposure pathway for humans. Two time scales control VOC partitioning: faster one (1.0 5.2 hours) describes reach equilibrium between adsorption desorption processes slower (4.8 21.2 ventilation overtake adsorption-desorption equilibria controlling concentration. These rates imply vapor pressure controls partitioning behavior house plays minor role removing VOCs. However, surface cleaning activities (vacuuming, mopping, dusting) physically removed reservoirs thus reduced concentrations more effectively than portable cleaners persistently window opening.

Language: Английский

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The Impact of Indoor Environments on the Abundance of Urban Outdoor VOCs

Environmental Science & Technology, Journal Year: 2025, Volume and Issue: unknown

Published: March 10, 2025

With the upcoming transition to clean electric vehicles, sources of volatile organic compounds (VOCs) in ambient environment are rapidly changing and highly uncertain. Here, through systematic characterization emissions from a typical apartment Chinese megacity (Shenzhen), we show that indoor environments contribute significantly levels (i.e., outdoor) VOCs. In particular, observe majority VOCs originate unoccupied spaces, demonstrating temperature-dependent release surface reservoirs. The total indoor-to-outdoor VOC emission rates varied 53 2300 mg day–1 (median 230 day–1) during periods, influenced by both air exchange rate temperature. Reanalysis literature data various building studies worldwide corroborates our findings reveals scale with room volume, an average 0.33 ± 0.03 h–1 m–3. Our study implies urban levels, rivaling traditional sources, e.g., power generation biomass burning. This is particularly true for oxygenated VOCs, such as methanol, amounting ∼60% transportation emissions. change understanding role contributions outdoor quality, whose importance will increase controls on industrial intensify.

Language: Английский

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Model Evaluation of Secondary Chemistry due to Disinfection of Indoor Air with Germicidal Ultraviolet Lamps

Environmental Science & Technology Letters, Journal Year: 2022, Volume and Issue: 10(1), P. 6 - 13

Published: Dec. 2, 2022

Air disinfection using germicidal ultraviolet light (GUV) has received increasing attention during the COVID-19 pandemic. GUV uses UVC lamps to inactivate microorganisms, but it also initiates photochemistry in air. However, GUV's indoor-air-quality impact not been investigated detail. Here, we model chemistry initiated by at 254 ("GUV254") or 222 nm ("GUV222") a typical indoor setting for different ventilation levels. Our analysis shows that GUV254, usually installed upper room, can significantly photolyze O3, generating OH radicals oxidize volatile organic compounds (VOCs) into more oxidized VOCs. Secondary aerosol (SOA) is formed as VOC-oxidation product. GUV254-induced SOA formation of order 0.1–1 μg/m3 cases studied here. GUV222 (described some harmless humans and thus applicable whole room) with same effective virus-removal rate makes smaller mid-to-high rates. This mainly because lower UV irradiance needed less efficient OH-generating O3 photolysis than GUV254. higher GUV254 under poor due small significant photochemical production nm, which does occur

Language: Английский

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Indoor and outdoor air quality impacts of cooking and cleaning emissions from a commercial kitchen

Environmental Science Processes & Impacts, Journal Year: 2023, Volume and Issue: 25(5), P. 964 - 979

Published: Jan. 1, 2023

Online gas- and particle-phase measurements in a commercial kitchen reveal exposure risks outdoor air impacts during cooking cleaning.

Language: Английский

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The Chemical Assessment of Surfaces and Air (CASA) Study: Using chemical and physical perturbations in a test house to investigate indoor processes

Environmental Science Processes & Impacts, Journal Year: 2024, Volume and Issue: unknown

Published: Jan. 1, 2024

The Chemical Assessment of Surfaces and Air (CASA) study aimed to understand how chemicals transform in the indoor environment using perturbations (

Language: Английский

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Detailed Investigation of the Contribution of Gas-Phase Air Contaminants to Exposure Risk during Indoor Activities

Environmental Science & Technology, Journal Year: 2022, Volume and Issue: 56(17), P. 12148 - 12157

Published: Aug. 11, 2022

Analytical capabilities in atmospheric chemistry provide new opportunities to investigate indoor air. HOMEChem was a chemically comprehensive field campaign designed how common activities, such as cooking and cleaning, impacted air test home. We combined gas-phase chemical data of all compounds, excluding those with concentrations <1 ppt, established databases health effect thresholds evaluate potential risks associated contaminants activities. The composition is distinct from outdoor air, gaseous compounds present at higher levels greater diversity─and thus predicted hazard quotients─indoors than outdoors. Common household activities like cleaning induce rapid changes composition, raising multiple high risk quotients. highlight strongly human influence the we breathe built environment, increasing exposure contaminants.

Language: Английский

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

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

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Ventilation in a Residential Building Brings Outdoor NO_x Indoors with Limited Implications for VOC Oxidation from NO₃ Radicals

Environmental Science & Technology, Journal Year: 2023, Volume and Issue: 57(43), P. 16446 - 16455

Published: Oct. 19, 2023

Energy-efficient residential building standards require the use of mechanical ventilation systems that replace indoor air with outdoor air. Transient pollution events can be transported indoors via system and other entry pathways impact chemistry. In spring 2022, we observed elevated levels NOx (NO + NO2) originated outdoors, entering National Institute Standards Technology (NIST) Net-Zero Energy Residential Test Facility through system. Using measurements NOx, ozone (O3), volatile organic compounds (VOCs), modeled effect outdoor-to-indoor on production nitrate radical (NO3), a potentially important oxidant. We evaluated how VOC oxidation chemistry was affected by NO3 during compared to background conditions. found nitric oxide (NO) introduced titrated O3 inhibited NO3. NO ventilated also likely ceased most gas-phase plume events. Only artificial introduction duct event (i.e., when NO2 concentrations were high relative typical conditions) able measure NO3-initiated products, indicating impacting

Language: Английский

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Reply on RC1

Published: Jan. 6, 2025

Abstract. Proton-transfer-reaction mass spectrometry (PTR-MS) using hydronium ion (H₃O⁺) ionization is widely used for the measurement of volatile organic compounds (VOCs) both indoors and outdoors. Unlike more energetic methods (e.g., electron impact), H₃O⁺ can leave a target VOC molecule mostly intact thus in PTR-MS spectrum be identified by its mass-to-charge ratio corresponding to proton-transfer product (MH⁺). However, ionization, associated chemistry reactor, known generate other ions besides product. The distributions (PIDs) created during include resulting from charge transfer reactions, water clustering, fragmentation, all which create ambiguity when interpreting spectra. A standardized method evaluating quantifying possible influence PIDs on spectra limited part due an incomplete understanding formation mechanisms effects instrument settings measured PIDs, as well reasons instrument-to-instrument variability. We present method, gas-chromatography pre-separation, measurements nearly 100 VOCs different functional types including alcohols, ketones, aldehydes, acids, aromatics, halogens, alkenes. Using this we highlight major contributions cluster fragment oxygenated VOCs. characterize ion-molecule reactor conditions, transmission quadrupole optic tuning, inlet capillary configuration PIDs. find that conditions have strongest impact but voltage differences also affect Through interlaboratory comparison calibration cylinders variability PID production same model across seven participating laboratories. subset laboratories had standard deviations (1 σ) with varied no than 20 % providing constraint predicting instruments operating under conditions. potential misidentification case study restroom air. propose identifying likely constraining Finally, library acquired study, publicly available updated periodically user-provided data continued investigation into

Language: Английский

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