UV-C Disinfection Research Articles

Mechanism of UV photodegradation of fluoroquinolone antibiotic ciprofloxacin in aqueous solutions.

Mechanism of direct UV photolysis of the zwitterionic and anionic forms of the quinolone antibiotic ciprofloxacin (CIP) was revealed by combination of nanosecond laser flash photolysis, steady-state photolysis coupled with high resolution LC-MS and DFT quantum-chemical calculations. For both forms, the main intermediate is a dissociative triplet state, which loses a fluorine ion to form a triplet carbocation; subsequent solvent attack of the latter leads to the formation of products of hydroxylation both the aromatic ring and the piperazyl substituent. Correspondingly, the quantum yield of photolysis of both CIP forms does not depend on the excitation wavelength, but depends on the concentration of dissolved oxygen. Secondary photolysis leads to a number of products of oxidation of the aromatic system, as well as oxidation, opening and full destruction of the piperazinyl substituent. The results obtained may be important for understanding the fate of quinolone antibiotics in UVC disinfection processes and in natural waters under the action of sunlight.

Biocompatibility of 3D-printed vs. thermoformed and heat-cured intraoral appliances.

The development of additive manufacturing has the potential to revolutionize the fabrication of medical devices. This technology, also known as 3D printing, offers precise, cost-effective, and personalized approaches, which could be particularly beneficial in the production of intraoral appliances. Despite its promise, research on the biocompatibility of 3D-printed intraoral devices is still limited. Our study aims to address this gap. We examined the cytotoxicity of materials processed via three techniques commonly used for the fabrication of different intraoral appliances: 3D printing (Dental LT Clear), thermoforming (Duran adjusted with Durasplint LC), and conventional heat-curing (Villacryl H Plus). We also investigated the impact of chemical or UVC disinfection on the biocompatibility of these materials. We assessed the biological effects induced in human gingival fibroblasts (HGFs) through both direct contact tests (MTT and LDH assays) and extract tests (PrestoBlue, DCF, and cell death type assays). Additionally, we observed changes in cellular morphology and migration rate under an inverted light microscope. The surface roughness of materials was evaluated using contact profilometry. Statistical analysis was conducted using two-way analysis of variance. Our findings suggest that all three fabrication techniques induced a slight cytotoxic effect in HGFs, as evidenced by both direct contact and extract tests. However, these materials could be considered nontoxic according to the ISO 10993-5:2009 norm, as the decrease in metabolic activity observed was always less than 30% compared to the untreated control. This novel study confirms that 3D printing may be a safe alternative to conventional methods for fabricating intraoral appliances. However, further tests assessing the long-term intraoral usage are still needed.

Decontamination Potential of Ultraviolet Type C Radiation in Water Treatment Systems: Targeting Microbial Inactivation

Access to safe water and sanitation is a critical global challenge, posing significant health risks worldwide due to waterborne diseases. This study investigates the efficacy of ultraviolet type C radiation as a disinfection method for improving water quality. The research elucidates UV-C’s mechanism of action, highlighting its ability to disrupt DNA and RNA replication, thereby inactivating pathogens. Furthermore, the study analyses the influence of key factors on UV-C disinfection effectiveness, including water turbidity and the presence of dissolved organic matter, which can attenuate UV-C penetration and reduce treatment efficiency. The experimental results demonstrate a substantial reduction in microbial content following UV-C treatment. River water samples exhibited a 57.143% reduction in microbial load, while well water samples showed a 50% reduction. Notably, Escherichia coli (E. coli) concentrations decreased significantly, with an 83.33% reduction in well water and a 62.5% reduction in borehole water. This study makes a novel contribution to the understanding of UV-C disinfection by identifying the presence of resistant organisms, including Adenoviruses, Bacterial spores, and the Protozoan Acanthamoeba, in water samples. This finding expands the scope of UV-C research beyond easily culturable bacteria. To address this challenge, future investigations should explore synergistic disinfection strategies, such as combining UV-C treatment with advanced oxidation processes. Optimising UV-C system designs and developing robust, real-time monitoring systems capable of detecting and quantifying known and emerging UV-resistant pathogens are crucial for ensuring comprehensive water decontamination.

An energy efficiency and cost analysis of utilizing high-intensity profile UVC systems on air handling unit under cool-humid climate

The feasibility of the ultraviolet germicidal irradiation (UVGI) application has been proven over the past few decades, especially in disinfection performances; however, a small number of studies were found that explored the energy efficiency improvement and cost savings of real buildings by implementing the UVC systems on cooling coils. The goal of this study is to verify the energy efficiency improvements and cost savings of AHU in a real building environment by removing biofilms on the cooling coil surfaces with the UVC irradiation techniques that can provide higher lamp output (300 μW/cm2) as well as higher intensity levels (1000–4000 μW/cm2) on the cooling coil surfaces. A series of experiments were conducted in an AHU in a medical center located in Michigan, US, to estimate energy efficiency improvement of cooling coils, chiller, and fan with UVC application. The results show that after 7 weeks of UVC operation increased coil overall enthalpy-based thermal conductance by 15.62 %, achieved chiller-side energy savings by up to 28.2 %, reduced pump energy by 32.1 %, and fan energy by 17.7 %. A return on investment (ROI) based only on energy savings is estimated to be 43 % and has a payback period of 2.32 years. When the labor, chemical, and water-saving costs for coil cleaning were included, the ROI was increased to 49 % and reduced the payback period to 2.04 years. When it comes to UVC's disinfection performances, six pathogens showed a more than 99 % removal rate while Klebsiella pneumoniae and Clostridium difficile showed a relatively lower 94 % removal rate.

Effect of UV-C disinfection, domestic and global experience

Effect of UV-C disinfection, domestic and global experience

Substrate influence in viral and bacteria UV-C disinfection

Substrate influence in viral and bacteria UV-C disinfection

UV-C side-emitting optical fiber-based disinfection: a promising approach for infection control in tight channels.

The growth of pathogenic bacteria in moist and wet surfaces and tubing of medically relevant devices results in serious infections in immunocompromised patients. In this study, we investigated and demonstrated the successful implementation of a UV-C side-emitting optical fiber in disinfecting medically relevant pathogenic bacteria (Pseudomonas aeruginosa and Methicillin-resistant Staphylococcus aureus [MRSA]) within tight channels of polytetrafluoroethylene (PTFE). PTFE is a commonly used material both in point-of-use (POU) water treatment technologies and medical devices (dental unit water line [DUWL], endoscope). For a 1-m-long PTFE channel, up to ≥6 log inactivation was achieved using a 1-m-long UV side-emitting optical fiber (SEOF) with continuous 16-h exposure of low UV-C radiation ranging from ~0.23 to ~29.30 μW/cm2. Furthermore, a linear model was used to calculate the inhibition zone constant (k`), which enables us to establish a correlation between UV dosage and the extent of inactivated surface area (cm2) for surface-bound Escherichia coli on a nutrient-rich medium. The k` value for an irradiance ranging from ~150 to ~271.50 μW/cm2 was calculated to be 0.564 ± 0.6 cm·cm2/mJ. This study demonstrated the efficacy of SEOFs for disinfection of medically relevant microorganisms present in medically and domestically relevant tight channels. The impact of the results in this study extends to the optimization of operational efficiency in pre-existing UV surface disinfection setups that currently operate at UV dosages exceeding the optimal levels.IMPORTANCEGermicidal UV radiation has gained global recognition for its effectiveness in water and surface disinfection. Recently, various works have illustrated the benefit of using UV-C side-emitting optical fibers (SEOFs) for the disinfection of tight polytetrafluoroethylene (PTFE) channels. This study now demonstrates its impact for disinfection of medically relevant organisms and introduces critical design calculations needed for its implementation. The flexible geometry and controlled emission of light in these UV-SEOFs make them ideal for light distribution in tight channels. Moreover, the results presented in this manuscript provide a novel framework that can be employed in various applications, addressing microbial contamination and the disinfection of tight channels.

UV- C Light Mobile Robotics System

Because diseases are spreading, cleaning enclosed places has become a critical concern. Various methods, including chemical-based solutions in liquid and gas forms, are commonly used for pathogen eradication. However, the environmental damage caused by these methods compounds existing challenges facing humanity. Additionally, UVC light, a promising alternative for disinfection, poses risks to human skin and eyes, necessitating precautions to prevent exposure. Moreover, the effectiveness of UVC disinfection is limited to directly exposed surfaces, rendering it challenging to utilize in occupied spaces where thorough disinfection is crucial. Furthermore, UVC light is less effective on porous surfaces like wood and fabric, further limiting its efficacy. The suggested solution incorporates UVC disinfection technology together with cleaning and drying features to overcome these issues. The objective is to improve the cleaning efficacy and efficiency of enclosed spaces by merging these elements. Both surface disinfection and impurity elimination are the main goals of the mopping and drying functions, which guarantee thorough cleaning. By using clever navigation algorithms to make sure all surfaces have direct exposure to UV-C lamps, the technology also overcomes the shortcomings of existing UVC disinfection. As porous surfaces react less well to UVC disinfection alone, the combination of cleaning and drying activities makes treatment possible. The proposed study provides a brief review of the methods used in sanitation with and without UV rays and the specific range of UV rays utilized in sanitation. It suggests an innovative UV-C sanitation robotic system that overcomes the shortcomings of existing UV-C disinfection systems.

The use of ultraviolet light generated from light-emitting diodes for the disinfection of transvaginal ultrasound probes.

Transvaginal ultrasound probes (TVUS) are used for several gynecological procedures. These need to be disinfected between patient use. In the current study we examine whether UVC delivered using light emitting diodes for 90 seconds can provide sufficient disinfection efficacy. A new UVC device that delivers UVC radiation at 265nm-275nm for 90 seconds was used. TVUS probes were swabbed before and after use in an in vitro fertilization clinic. Microbes on the swabs were cultured and identified. In addition, the ability of the UVC device to provided repeated high-level disinfection was analysed by deliberately contaminating probes with spores of Bacillus subtilis and then performing the UVC disinfection and bacterial culture. 50% of probes were contaminated with bacteria, most commonly Bacillus sp., directly after in vivo use. Whereas 97% were sterile after UVC disinfection for 90 seconds. The UVC treatment resulted in no growth of B. subtilis spores after each of five repeated contaminations with 5-9 x 107 spores on the probes. This study has found that UVC delivered via light emitting diodes for only 90 seconds can produce high level disinfection of transvaginal probes.

RoboCoV Cleaner: An Indoor Autonomous UV-C Disinfection Robot with Advanced Dual-Safety Systems.

In the face of today's ever-evolving global health landscape and ambient assisted living (AAL), marked by the persistent emergence of novel viruses and diseases that impact vulnerable categories and individual safety, the need for innovative disinfection solutions has surged to unprecedented levels. In pursuit of advancing the field of autonomous UV-C disinfection robotics, we conducted two comprehensive state-of-the-art analyses: the first one in the literature and the second one in existing commercial disinfection robots to identify current challenges. Of all of the challenges, we consider the most outstanding ones to be safeguarding humans and animals and understanding the surroundings while operating the disinfection process challenges that we will address in this article. While UV-C lamps have demonstrated their effectiveness in sterilizing air and surfaces, the field of autonomous UV-C disinfection robotics represents a critical domain that requires advancement, particularly in safeguarding the wellbeing of humans and animals during operation. Operating UV-C disinfection robots in close proximity to humans or animals introduces inherent risks, and existing disinfection robots often fall short in incorporating advanced safety systems. In response to these challenges, we propose the RoboCoV Cleaner-an indoor autonomous UV-C disinfection robot equipped with an advanced dual and redundant safety system. This novel approach incorporates multiple passive infrared (PIR) sensors and AI object detection on a 360-degree camera. Under our test, the dual-redundant system reached more than 90% when detecting humans with high accuracy using the AI system 99% up to 30 m away in a university hallway (different light conditions) combined with the PIR system (with lower accuracy). The PIR system was proved to be a redundant system for uninterrupted operation during communication challenges, ensuring continuous sensor information collection with a swift response time of 50 ms (image processing within 200 ms). It empowers the robot to detect and react to human presence, even under challenging conditions, such as when individuals wear masks, in complete darkness, under UV light, or in environments with blurred visual conditions. In our test, the detection system performed outstandingly well with up to 99% detection rate of humans. Beyond safety features, the RoboCoV Cleaner can identify objects in its surroundings. This capability empowers the robot to discern objects affected by UV-C light, enabling it to apply specialized rules for targeted disinfection. The proposed system exhibits a wide range of capabilities beyond its core purpose of disinfection, making it suitable for healthcare facilities, universities, conference venues, and hospitals. Its implementation has the ability to improve significantly human safety and protect people. By showcasing the RoboCoV Cleaner's safety-first approach and adaptability, we aim to set a new benchmark for UV-C disinfection robots, promoting clean and secure environments while protecting vulnerable people, even in challenging scenarios.

SARS-CoV-2 Inactivation on Hard Non-porous Airplane Cabin Material Surfaces was Limited After Exposure to Far UV-C (222 nm) Radiation.

To test the efficacy of 222 nm Far UV-C for surface disinfection of SARS-CoV-2 on inanimate surfaces from airplane cabins. Two far ultraviolet (UV-C) irradiation light systems were evaluated for disinfection of SARS-CoV-2. Materials used for carriers (test surfaces) included polished stainless steel and used airplane materials including seatbelt latches, window dust covers, sidewall laminates, and tray tables. While demonstrating reasonable efficacy under some experimental conditions, the data indicated that 222 nm Far UV-C disinfection alone does not reliably provide a 3 log10 or 99.9% reduction of SARS-CoV-2 on inanimate surfaces from an airplane cabin. An Ushio (Cypress, CA) 1.7" x 2.3" Care222® 12W 222nm BI lamp module tested in triplicate at a low (⁓ 1.5 mJ cm-2), medium (⁓ 3.0 mJ cm-2), and high (⁓ 6 to 9 mJ cm-2) fluence did not provide a ≥ 3 log10 or 99.9% reduction of SARS-CoV-2. The reduction of SARS-CoV-2 was greatest on stainless steel. The result was a log10 reduction of 2.83, 1.33, 2.58, and 2.21 logs for virus samples containing saline, saline with 2.5 mg BSA, saline with 0.25 mg BSA, and artificial saliva respectively at a dosage of 5 to 9 mJ cm-2. The log10 reduction of SARS-CoV-2 in saline with 2.5 mg bovine serum albumin was lowest with 1.33 for stainless steel, 0.93 for belt latch, and 0.61 for tray table at a dosage of 5 to 6 mJ cm-2.The second UV lighting system tested was a prototype mobile wand with a built-in short-pass filtered krypton-chloride cylindrical lamp. One pass of the wand over a tray holding carriers inoculated with SARS-CoV-2 in artificial saliva at a rate of approximately 1 foot (1') per second (sec) exposed the carriers to 7.3 mJ cm-2. The log10 reductions determined for the single pass were 2.97, 3.75, 1.78, 1.91, and 1.28 logs for stainless steel, belt latch, dust cover, sidewall, and tray table respectively. Two passes of the wand generated 17.2 mJ cm-2 and resulted in log10 reductions of 4.04, 3.74, 4.24, 3.68, and 1.66 logs for stainless steel, belt latch, dust cover, sidewall, and tray table respectively. The combination of higher fluence from multiple passes of the wand, the close proximity (10 cm wand to the carrier), the exposure to elevated temperatures up to 35°C, and ozone from the bulb being blown directly onto the carriers contributed to effective viral inactivation on all surfaces except the airplane tray table. The impact of temperature and ozone on viral inactivation should be determined for future testing of the 222 nm UV-C wand.

Revolutionizing Infection Control: Autonomous UV-C Disinfection Robots in Healthcare Environments

Healthcare-associated Infections (HAIs) continue to present a significant challenge in healthcare settings, particularly within operating rooms and patient rooms where the risk of contamination is high. Despite rigorous cleaning protocols, traditional methods often struggle to fully eradicate microorganisms, contributing to a notable percentage of HAIs, especially among surgical patients. This paper examines the potential of ultraviolet (UV) light technology, specifically within the C band range (200-280nm), as a promising adjunct to conventional cleaning practices. UV-C light has demonstrated remarkable efficacy in deactivating bacteria, viruses, and fungi by disrupting their DNA, rendering them incapable of replication. This technology offers a versatile solution for sterilizing air, water, and surfaces, including hard-to-reach areas inaccessible to manual cleaning. Incorporating UV-C robots into routine cleaning procedures holds promise in augmenting the effectiveness of environmental decontamination efforts. By addressing the limitations of traditional cleaning methods and targeting residual pathogens, the integration of UV-C technology has the potential to significantly reduce the incidence of HAIs. Furthermore, the implementation of UV-C robots in healthcare facilities could lead to improved patient outcomes, reduced healthcare costs associated with treating HAIs, and a safer environment for both patients and healthcare workers. This paper synthesizes current evidence and highlights the implications of adopting UV-C technology as a crucial step toward enhancing infection control measures in healthcare settings.

Hybrid Radiant Disinfection: Exploring UVC and UVB Sterilization Impact on the Mechanical Characteristics of PLA Materials.

This study explores the impact of disinfection techniques on the mechanical properties of poly(lactic acid) (PLA), a crucial material in the production of medical implants, tissue engineering, orthopedic devices and drug delivery systems, owing to its biocompatibility and ease of manufacturing. The focus is on evaluating the effectiveness of ultraviolet (UV) type C (254 nm wavelength) and the combined use of type C and B (310 nm wavelength) disinfection methods. Fifteen tensile test specimens (ASTM D638) and fifteen compression test specimens (ASTM D695) were utilized to assess PLA's mechanical properties, including yield strength, ultimate strength, and fracture strength. The investigation involved subjecting the specimens to the specified disinfection methods and evaluating these properties both before and after the disinfection process. In the tensile test, a statistically significant difference (p = 0) in yield displacement was observed among the three groups. Additionally, a notable difference (p = 0.047) in fracture displacement was identified between the untreated group and the UVC and UVB combination group. No discernible impact on yield or fracture forces was noted. In the compression test, there was a significant difference (p = 0.04) in yield displacement and a clear difference (p = 0.05) in fracture force between the untreated group and the UVC and UVB combination group. The hybrid combination of UVC and UVB disinfection techniques did not affect yield force in both tensile and compression tests. However, it demonstrated a clear impact on displacement, suggesting its potential as a promising disinfection technique in the medical field.

Evaluation of the Efficacy of UV-C Radiation in Eliminating Microorganisms of Special Epidemiological Importance from Touch Surfaces under Laboratory Conditions and in the Hospital Environment

Introduction: Healthcare-associated infections in the post-pandemic era are as important as they were before COVID-19. The dominant route of transmission of microorganisms in health care units is the contact route, for which hand hygiene is of cardinal importance, but also effective disinfection of touch surfaces. Traditional disinfection based on chemical compounds is sensitive to human errors. Therefore, a valuable supplement to it can be contactless disinfection methods, including the use of UV-C. The aim of the study was to assess the effectiveness of UV-C radiation in eliminating selected, most important pathogens of particular epidemic importance from surfaces made of various materials: stainless steel, plastic and glass, most often found in hospital conditions. Material and Method: In laboratory conditions, the study was conducted using bacterial strains of great epidemiological importance and Candida auris. In hospital wards, samples were taken before and after disinfection for comparisons of the composition and quantity of bacteria. In laboratory conditions, carriers made of steel, plastic and glass were contaminated with a bacterial suspension with a density of approx. 0.5 McFarland, and then the density of persistent microorganisms was assessed after 10 min of UV-C irradiation. Results: The high effectiveness of UV-C radiation in eliminating bacteria contaminating touch surfaces in hospital wards and in laboratory conditions has been confirmed. The elimination efficiency in laboratory conditions was slightly lower (statistically insignificant) on the plastic surface, which is probably related to subtle differences in the thickness of the contaminating layer. Hydrophobic properties and the smallest suspension diameter were confirmed for the tested plastic carriers. Conclusions: UV-C disinfection is a desirable element to support traditional, chemical methods of disinfection in hospital conditions, effective against multidrug-resistant bacteria and C. auris.

Numerical Model and System for Prediction and Reduction of Indoor Infection Risk

Abstract The developed numerical model assesses the risk of a COVID-19 infection in a room based on the measurements of temperature, relative humidity, CO2 and particle concentration, as well as the number of people and occurrences of speech, coughing, and sneezing obtained through a low-cost sensor system. As the model operates faster than real-time, it can dynamically inform the persons in the room or building management system about the predicted risk level. When the infection risk is high, the model can activate an air purifier equipped with filtration and UV-C disinfection. This solution improves energy efficiency by reducing the ventilation intensity required during colder seasons to maintain the same safety level and activating the purifier only when the predicted infection risk surpasses a specified threshold.

Enhancing Disinfection Efficiency of Wastewater Treatment Plant Effluent: The Role of ZnO Nanoparticles in Ultrasonic and UV-C Processes

Ultrasonic (US) and UV-C disinfection technologies have been successfully used in wastewater treatment plants (WWTPs) for disinfection purposes. The US technology is typically used as a pre-treatment step to break down larger particles and make them more susceptible to disinfection. The UV-C technology is commonly used as a final disinfection step in many WWTPs. The study aimed to assess the potential of using Zinc Oxide (ZnO) Nanoparticles (NPs) to improve the effectiveness of UV-C and US disinfection methods in treating wastewater effluent, offering a more comprehensive solution to wastewater treatment. In this experimental study, a Laboratory US Bath (40[Formula: see text]kHz) and a UV-C lamp (16[Formula: see text]W) were used. In order to investigate the effectiveness of ZnO NPs in the reduction of microbial load, 5[Formula: see text]mg/L of ZnO NPs was added to the effluent samples. Then, samples were examined for Total Coliform (TC) and Fecal Coliform (FC) reduction by the standard MPN/100[Formula: see text]mL test. The Chick‘s law was used to calculate the efficiency of microbial load. The relationship between variables was determined by regression analysis using Excel and SPSS-ver 21 software. In this study, the samples were examined in three groups: Samples that were only exposed to sonication or received UV-C radiation with Turbidity of 18 NTU (Group A) and Turbidity of 5 NTU (Group B), and Samples that received 5 mg/L of ZnO NPs (Group C). By increasing the time from 0.5 min to 10 min in the presence of UV-C, the amount of microbial population decreased, and 2 min was considered the optimal time. The maximum removal efficiencies by US for TC were 74.07,77.7, 85.1% (40∘C) and 92.5,100, and 100% (60∘C) in group A (in 30 min sonication), 85.7, 85.7, 100% (40∘C), respectively, and were 100% in other groups (B and C), respectively. The maximum removal efficiencies by US for FC were 76.4%, 88.2%, and 100% (40∘C) and 88.2%, 100%, and 100% (60∘C) in group A (in 30 min sonication), respectively, and were 100% in other groups (B and C). In this study, an important increase in the disinfection ability of ZnO NPs has been observed in the presence of US and UV-C. So, the ZnO NPs/UV-C and ZnO NPs/US processes are valuable alternatives to conventional disinfection processes by over 90% improvement of disinfection efficiency.

Reduction of airborne and surface-borne bacteria in a medical center burn intensive care unit using active, upper-room, germicidal ultraviolet (GUV) disinfection.

To determine the effectiveness of active, upper-room, germicidal ultraviolet (GUV) devices in reducing bacterial contamination in patient rooms in air and on surfaces as a supplement to the central heating, ventilation, and air conditioning (HVAC) air handling unit (AHU) with MERV 14 filters and UV-C disinfection. This study was conducted in an academic medical center, burn intensive care unit (BICU), for 4 months in 2022. Room occupancy was monitored and recorded. In total, 402 preinstallation and postinstallation bacterial air and non-high-touch surface samples were obtained from 10 BICU patient rooms. Airborne particle counts were measured in the rooms, and bacterial air samples were obtained from the patient-room supply air vents and outdoor air, before and after the intervention. After preintervention samples were obtained, an active, upper-room, GUV air disinfection system was deployed in each of the patient rooms in the BICU. The average levels of airborne bacteria of 395 CFU/m3 before GUV device installation and 37 CFU/m3 after installation indicated an 89% overall decrease (P < .0001). Levels of surface-borne bacteria were associated with a 69% decrease (P < .0001) after GUV device installation. Outdoor levels of airborne bacteria averaged 341 CFU/m3 in March before installation and 676 CFU/m3 in June after installation, but this increase was not significant (P = .517). Significant reductions in air and surface contamination occurred in all rooms and areas and were not associated with variations in outdoor air concentrations of bacteria. The significant decrease of surface bacteria is an unexpected benefit associated with in-room GUV air disinfection, which can potentially reduce overall bioburden.

Development of innovative health guardian: UV-C disinfection with solar battery charging

In today's world, the advancement of standard technology is accompanied by various challenges. The year 2019 experienced significant challenges that led to changes in several areas, particularly health. Most horrifyingly, many knowledgeable researchers and medical professionals have tried to find the solution but failed. This virus has not yet been cured. Many nations have proclaimed a state of emergency and issued movement control directives due to the virus's millions of fatalities and deep psychological scars. As a result, the government has taken several steps to stop the spread. However, The COVID-19 issue is still a challenge even after the availability of medicine and vaccine. Consequently, this effort is a step towards assisting us in avoiding this deadly infection. The initiative uses light technology, which efficiently kills viruses in water, air and germs. There are three types of UV rays: UV-A, UV-B, and UV-C. The nanometer-scale wavelength of these lights distinguishes them from one another. The wavelengths between 100 and 280nm are the most efficient for this eradication procedure. Additionally, this project makes use of solar-generated renewable energy. In conclusion, we always have strategies to avoid these COVID-19 symptoms because of the currents of modernity.

Ultraviolet-C mediated inactivation of Candida auris, a rapid emerging health threat

Health care-associated infections, particularly those caused by multidrug-resistant organisms (MDROs), pose significant challenges to patient safety. Candida auris (C auris), an emerging MDRO fungus, has been acknowledged as an urgent threat by the Centers for Disease Control and Prevention due to its high mortality and difficulty in prevention, diagnosis, and treatment. In this study, we investigated the efficacy of 254nm ultraviolet-C light (UV-C) in inactivating C auris on hard surfaces. A mobile UV-C tower equipped with high-performance bulbs was used, and within 7minutes of continuous exposure, ≥99.97% (≥3.86 log10) inactivation of C auris was achieved in a patient-room-sized test chamber. Our findings suggest that UV-C can serve as an adjunct infection control measure for preventing C auris and other MDRO Health care-associated infections in health care settings. Implementation of UV-C disinfection protocols can contribute to enhanced patient safety and combat the growing threat of MDRO pathogens.

Developing a survival probability-based Lagrangian model for predicting ultraviolet disinfection of bioaerosols in enclosed environments

The transmission of airborne infectious diseases in enclosed environments has become a significant public health issue. Far-ultraviolet C (UVC) lights can be used safely and effectively to disinfect bioaerosols and reduce the risk of airborne infectious disease transmission. To ensure proper use of far-UVC systems, an improved Lagrangian method for predicting the dispersion, deposition, and far-UVC disinfection of bioaerosols was proposed. First, an improved Lagrangian model considering the probability of bioaerosol survival was developed for predicting the UVC disinfection of airborne bioaerosols in enclosed environments. The UVC disinfection of surfaces with deposited bioaerosols was implemented into the deposition module of the Lagrangian model by introducing the concept of equivalent deposition number. Experimental data on far-UVC disinfection of E. Coli in the air and on the surfaces in a ventilated chamber were used to validate the proposed model. The validation results show that the proposed model can predict the bioaerosol dispersion, deposition, and far-UVC disinfection reasonably well. The validated model was then employed to calculate the far-UVC disinfection of airborne and surface SARS-CoV-2 bioaerosols in a Mass Transit Railway (MTR) train compartment in Hong Kong. According to the calculation results, the far-UVC lamps are effective in reducing the passengers’ exposure to SARS-CoV-2 bioaerosols.