Formaldehyde Vapor Characteristics in Varied Decontamination Environments

Choi, Young Wook; Sunderman, Michelle; McCauley, Martha W.; Richter, William R.; Willenberg, Zachary J.; Wood, Joseph P.; Serre, Shannon; Mickelsen, Leroy; Willison, Stuart A.; Rupert, Rich; Ortiz, Jorge G. Muñiz; Casey, S.R.; Calfee, M. Worth

doi:10.1089/apb.21.926968

Cited by 3 publications

(4 citation statements)

References 20 publications

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“…However, surface porosity is not the sole factor influencing the effective dose at the surface of a material; further work would be required to verify the effect of surface roughness (effecting formulation wetting), organic content (material demand could reduce available formalin for spore interaction) or the effect of different meteorological conditions (temperature, humidity and solar irradiation) on the hazard reduction levels achieved employing the above application regimes. Such environmental and surface chemical demand factors have been studied under controlled test chamber conditions to determine their effect on the concentration of formalin when applied as a vapour for biological decontamination (Choi et al, 2021 ). In that study, there was no discolouration or change in physical appearance of material coupons (painted cinder block concrete and bare pine wood) or test chamber components upon formalin vapour exposure (Choi et al, 2021 ).…”

Section: Discussionmentioning

confidence: 99%

“…Such environmental and surface chemical demand factors have been studied under controlled test chamber conditions to determine their effect on the concentration of formalin when applied as a vapour for biological decontamination (Choi et al, 2021 ). In that study, there was no discolouration or change in physical appearance of material coupons (painted cinder block concrete and bare pine wood) or test chamber components upon formalin vapour exposure (Choi et al, 2021 ). The chemical compatibility of formalin is greater across a wide range of material types (polymers, metals, rubber) than common oxidant decontaminants, such as sodium hypochlorite (Cole Palmer Chemical Compatibility Database, 2022 ).…”

Section: Discussionmentioning

confidence: 99%

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Dose–response analysis of Bacillus thuringiensis HD-1 cry- spore reduction on surfaces using formaldehyde with pre-germination

Gazi

Bayliss

O'Sullivan³

et al. 2022

Journal of Applied Microbiology

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Aim To establish a basis for rapid remediation of large areas contaminated with Bacillus anthracis spores. Methods and Results Representative surfaces of wood, steel and cement were coated by nebulization with B. thuringiensis HD‐1 cry‐ (a simulant for B. anthracis) at 5.9 ± 0.2, 6.3 ± 0.2 and 5.8 ± 0.2 log10 CFU per cm2, respectively. These were sprayed with formaldehyde, either with or without pre‐germination. Low volume (equivalent to ≤2500 L ha−1) applications of formaldehyde at 30 g l−1 to steel or cement surfaces resulted in ≥4 or ≤2 log10 CFU per cm2 reductions respectively, after 2 h exposure. Pre‐germinating spores (500 mmol l−1 l‐alanine and 25 mmol l−1 inosine, pH 7) followed by formaldehyde application showed higher levels of spore inactivation than formaldehyde alone with gains of up to 3.4 log10 CFU per cm2 for a given dose. No loss in B. thuringiensis cry‐ viability was measured after the 2 h germination period, however, a pre‐heat shock log10 reduction was seen for B. anthracis strains: LSU149 (1.7 log10), Vollum and LSU465 (both 0.9 log10), LSU442 (0.2 log10), Sterne (0.8 log10) and Ames (0.6 log10). Conclusions A methodology was developed to produce representative spore contamination of surfaces along with a laboratory‐based technique to measure the efficacy of decontamination. Dose–response analysis was used to optimize decontamination. Pre‐germinating spores was found to increase effectiveness of decontamination but requires careful consideration of total volume used (germinant and decontaminant) by surface type. Significance and Impact of the Study To be practically achievable, decontamination of a wide area contaminated with B. anthracis spores must be effective, timely and minimize the amount of materials required. This study uses systematic dose–response methodology to demonstrate that such an approach is feasible.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Dose–response analysis of Bacillus thuringiensis HD-1 cry- spore reduction on surfaces using formaldehyde with pre-germination

Gazi

Bayliss

O'Sullivan³

et al. 2022

Journal of Applied Microbiology

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“…Indeed, high viral loads of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can be found in both asymptomatic [ 2 ] and positive patients [ 3 ]. Decontamination of used facemasks (textile and if possible FFP and surgical) is a common practice to enable their reuse and thus mitigate the shortage risk [ 4 , 5 ], as well as the potential ecological impact of disposable units worn by billions of daily users [ 1 , 6 ]. Slightly different from disinfection (which kills microorganisms on contaminated surfaces), decontamination reduces (typically, a 5 log reduction) the microbial contamination of materials or surfaces to an acceptably safe level to avoid contamination.…”

Section: Introductionmentioning

confidence: 99%

“…In droplets, the humidity rate and the evaporation kinetics of water can produce [ 12 ] an intermediate evaporation rate and a high concentration of salts, leading to virus inactivation. Unfortunately, all previous studies have been carried out in constant conditions over time, and these are not easily met in a domestic setting (constant temperature and humidity require sensors and a regulation system) [ 5 ].…”

Section: Introductionmentioning

confidence: 99%

The properties of hot household hygroscopic materials and their potential use for non-medical facemask decontamination

et al. 2021

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The widespread use of facemasks throughout the population is recommended by the WHO to reduce transmission of the SARS-CoV-2 virus. As some regions of the world are facing mask shortages, reuse may be necessary. However, used masks are considered as a potential hazard that may spread and transmit disease if they are not decontaminated correctly and systematically before reuse. As a result, the inappropriate decontamination practices that are commonly witnessed in the general public are challenging management of the epidemic at a large scale. To achieve public acceptance and implementation, decontamination procedures need to be low-cost and simple. We propose the use of hot hygroscopic materials to decontaminate non-medical facemasks in household settings. We report on the inactivation of a viral load on a facial mask exposed to hot hygroscopic materials for 15 minutes. As opposed to recent academic studies whereby decontamination is achieved by maintaining heat and humidity above a given value, a more flexible procedure is proposed here using a slow decaying pattern, which is both effective and easier to implement, suggesting straightforward public deployment and hence reliable implementation by the population.

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Low-Cost Formaldehyde Sensor Evaluation and Calibration in a Controlled Environment

Chattopadhyay

Huertas²,

Rebeiro‐Hargrave

et al. 2022

IEEE Sensors J.

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Formaldehyde is a carcinogenic indoor air pollutant emitted from common wood-based materials. Low-cost sensing of formaldehyde is difficult due to inaccuracies in measuring low concentrations and susceptibility of sensors to changing indoor environmental conditions. Currently gas sensors are calibrated by manufacturers using simplistic models which fail to capture their complex behaviour. We evaluated different low-cost gas sensors to ascertain a suitable component to create a mobile sensing node and built a calibration algorithm to correct it. We compared the performance of 2 electrochemical sensors and 3 metal oxide sensors in a controlled chamber against a photo-acoustic reference device. In the chamber the formaldehyde concentrations, temperature and humidity were varied to assess the sensors in diverse environments. Pre-calibration, the electrochemical sensors (mean absolute error (MAE) = 70.8 ppb) outperformed the best performing metal oxide sensor (MAE = 335 ppb). A two-stage calibration model was built, using linear regression followed by random forest, where the residual of the first stage acted as a input for the second. Post-calibration, the metal oxide sensors (MAE = 154 ppb) improved compared to their electrochemical counterparts (MAE = 78.8 ppb). Nevertheless, the uncalibrated electrochemical sensor showed overall superior performance hence was selected for the mobile sensing node.

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Formaldehyde Vapor Characteristics in Varied Decontamination Environments

Cited by 3 publications

References 20 publications

Dose–response analysis of Bacillus thuringiensis HD-1 cry- spore reduction on surfaces using formaldehyde with pre-germination

Dose–response analysis of Bacillus thuringiensis HD-1 cry- spore reduction on surfaces using formaldehyde with pre-germination

The properties of hot household hygroscopic materials and their potential use for non-medical facemask decontamination

Low-Cost Formaldehyde Sensor Evaluation and Calibration in a Controlled Environment

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