Efficacy of the Precise Climate Controller on the reduction of indoor microorganisms

Moungthong, Greetha; Klamkam, Pana; Mahakit, Prasit; Chalermwatanachai, Thanit; Thunyaharn, Sudaluck; Monyakul, Veerapol

doi:10.5415/apallergy.2014.4.2.113

Cited by 5 publications

(4 citation statements)

References 14 publications

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“…In a hospital room maintained at constant temperature and RH (25°C and 55%, respectively), fungal and bacterial cells were identified from air samples for at least 3 days; however, by day 6, no fungal or bacterial colonies were obtained from the air samples (Moungthong et al, 2014 ). Although these studies cannot confirm whether a certain room temperature and RH suppress the growth of indoor bacteria, they do suggest that both factors control microbial communities.…”

Section: Measured Factors At the Time Of Airborne Bacterial Sampling mentioning

confidence: 99%

Transmission of Airborne Bacteria across Built Environments and Its Measurement Standards: A Review

2017

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Human health is influenced by various factors including microorganisms present in built environments where people spend most of their lives (approximately 90%). It is therefore necessary to monitor and control indoor airborne microbes for occupational safety and public health. Most studies concerning airborne microorganisms have focused on fungi, with scant data available concerning bacteria. The present review considers papers published from 2010 to 2017 approximately and factors affecting properties of indoor airborne bacteria (communities and concentration) with respect to temporal perspective and to multiscale interaction viewpoint. From a temporal perspective, bacterial concentrations in built environments change depending on numbers of human occupancy, while properties of bacterial communities tend to remain stable. Similarly, the bacteria found in social and community spaces such as offices, classrooms and hospitals are mainly associated with human occupancy. Other major sources of indoor airborne bacteria are (i) outdoor environments, and (ii) the building materials themselves. Indoor bacterial communities and concentrations are varied with varying interferences by outdoor environment. Airborne bacteria from the outdoor environment enter an indoor space through open doors and windows, while indoor bacteria are simultaneously released to the outer environment. Outdoor bacterial communities and their concentrations are also affected by geographical factors such as types of land use and their spatial distribution. The bacteria found in built environments therefore originate from any of the natural and man-made surroundings around humans. Therefore, to better understand the factors influencing bacterial concentrations and communities in built environments, we should study all the environments that humans contact as a single ecosystem. In this review, we propose the establishment of a standard procedure for assessing properties of indoor airborne bacteria using four factors: temperature, relative humidity (RH), air exchange rate, and occupant density, as a minimum requirement. We also summarize the relevant legislation by country. Choice of factors to measure remain controversial are discussed.

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Section: Measured Factors At the Time Of Airborne Bacterial Sampling mentioning

confidence: 99%

Transmission of Airborne Bacteria across Built Environments and Its Measurement Standards: A Review

2017

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“…It has been known for quite a long time [ANSI/ASHRAE, 2012] that, in spaces with air speed less than 0.2 m/s, the RH within the range of 40 < RH < 60 and the temperature within the range of 22-27 • C together provide a comfort zone for humans and, meanwhile, this condition can eliminate pathogens (e.g. viruses, bacteria, funguses) and allergic substances as well as reducing or even eradicating house dust mites [Arlian et al, 2001;Moungthong et al, 2014;Sookchaiya et al, 2010].…”

Section: Engineering Design For Indoor Climate Controlmentioning

confidence: 99%

“…Next, to design and implement a real indoor climate control system, two benchmark models are reviewed to reveal some basic ideas. In [Moungthong et al, 2014] the room is closed for 20 days. The climate control results demonstrated that, for the first three days, there are nine A. flavus colonies found in the room.…”

Section: Engineering Design For Indoor Climate Controlmentioning

confidence: 99%

Chen System as a Controlled Weather Model — Physical Principle, Engineering Design and Real Applications

Sooraksa

Chen

2018

Int. J. Bifurcation Chaos

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This paper presents the Chen system as a controlled weather model. Mathematically, the Chen system is dual to the Lorenz system via time reversal. Physically, the Chen system can be viewed as a controlled weather model from the anti-control perspective. This paper illustrates the physical principle of this controlled weather model, and develops an engineering design of the model for real indoor climate (temperature-humidity) regulation, with a perspective on outdoor weather control application.

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“…On the basis of recent research, the influence of individual environmental factors on airborne bacteria is becoming increasingly evident. For example, in a hospital room maintained at constant temperature and humidity (25°C and 55%), similar types of fungi and bacteria were identified over at least 3 days from air samples [ 16 ]. Furthermore, the study of airborne bacteria in patient rooms showed that the diversity and composition of the indoor bacterial communities changed readily in response to variations in ventilation or temperature [ 17 ].…”

Section: Introductionmentioning

confidence: 99%

Differential impact of environmental factors on airborne live bacteria and inorganic particles in an underground walkway

Yamaguchi,

Okubo,

Nozaki

et al. 2024

PLoS ONE

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We previously reported that variations in the number and type of bacteria found in public spaces are influenced by environmental factors. However, based on field survey data alone, whether the dynamics of bacteria in the air change as a result of a single environmental factor or multiple factors working together remains unclear. To address this, mathematical modeling may be applied. We therefore conducted a reanalysis of the previously acquired data using principal component analysis (PCA) in conjunction with a generalized linear model (Glm2) and a statistical analysis of variance (ANOVA) test employing the χ2 distribution. The data used for the analysis were reused from a previous public environmental survey conducted at 8:00–20:00 on May 2, June 1, and July 5, 2016 (regular sampling) and at 5:50–7:50 and 20:15–24:15 on July 17, 2017 (baseline sampling) in the Sapporo underground walking space, a 520-meter-long underground walkway. The dataset consisted of 60 samples (22 samples for “bacterial flora”), including variables such as “temperature (T),” “humidity (H),” “atmospheric pressure (A),” “traffic pedestrians (TP),” “number of inorganic particles (Δ5: 1–5 μm),” “number of live airborne bacteria,” and “bacterial flora.” Our PCA with these environmental factors (T, H, A, and TP) revealed that the 60 samples could be categorized into four groups (G1 to G4), primarily based on variations in PC1 [Loadings: T(˗0.62), H(˗0.647), TP(0.399), A(0.196)] and PC2 [Loadings: A(˗0.825), TP(0.501), H(0.209), T(˗0.155)]. Notably, the number of inorganic particles significantly increased from G4 to G1, but the count of live bacteria was highest in G2, with no other clear pattern. Further analysis with Glm2 indicated that changes in inorganic particles could largely be explained by two variables (H/TP), while live bacteria levels were influenced by all explanatory variables (TP/A/H/T). ANOVA tests confirmed that inorganic particles and live bacteria were influenced by different factors. Moreover, there were minimal changes in bacterial flora observed among the groups (G1–G4). In conclusion, our findings suggest that the dynamics of live bacteria in the underground walkway differ from those of inorganic particles and are regulated in a complex manner by multiple environmental factors. This discovery may contribute to improving public health in urban settings.

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Efficacy of the Precise Climate Controller on the reduction of indoor microorganisms

Cited by 5 publications

References 14 publications

Transmission of Airborne Bacteria across Built Environments and Its Measurement Standards: A Review

Transmission of Airborne Bacteria across Built Environments and Its Measurement Standards: A Review

Chen System as a Controlled Weather Model — Physical Principle, Engineering Design and Real Applications

Differential impact of environmental factors on airborne live bacteria and inorganic particles in an underground walkway

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