Source Of Ultraviolet Radiation Research Articles

Flexible and Ecological Cotton-Based Dosimeter for 2D UV Surface Dose Distribution Measurements.

This work presents a 2D radiochromic dosimeter for ultraviolet (UV) radiation measurements, based on cotton fabric volume-modified with nitroblue tetrazolium chloride (NBT) as a radiation-sensitive compound. The developed dosimeter is flexible, which allows it to adapt to various shapes and show a color change from yellowish to purple-brown during irradiation. The intensity of the color change depends on the type of UV radiation and is the highest for UVC (253.7 nm). It has been shown that the developed dosimeters (i) can be used for UVC radiation dose measurements in the range of up to 10 J/cm2; (ii) can be measured in 2D using a flatbed scanner; and (iii) can have the obtained images after scanning be filtered with a medium filter to improve their quality by reducing noise from the fabric structure. The developed cotton-NBT dosimeters can measure UVC-absorbed radiation doses on objects of various shapes, and when combined with a dedicated computer software package and a data processing method, they form a comprehensive system for measuring dose distributions for objects with complex shapes. The developed system can also serve as a comprehensive method for assessing the quality and control of UV radiation sources used in various industrial processes.

Effect of electrophysical treatments on the storage life of potatoes and other vegetable crops

To prevent the progression of various infectious diseases, seed and planting material must undergo treatment with ultraviolet (UV) radiation at an intensity of 10-15 kilojoules. This necessitates studying the impact of UV radiation on products as they move in a flow along a conveyor belt. (Research purpose) The study aims to evaluate the feasibility of using ultraviolet radiation to improve the storage indicators of potato and other vegetable crops. It also assesses the technological parameters in both laboratory and production settings to ensure a reduction in contamination. (Materials and methods) To determine the optimal technological parameters of a machine for processing vegetable crops and potatoes before storage in the post-harvest processing system, an experimental installation was created and the electrophysical effects on storage quality indicators were examined. For the study, the most common vegetable crop varieties were selected, in particular, Lady Rosetta potato, Vitaminnaya-6 table carrot and Bordeaux 237 table beet. These crops are cultivated under various soil and climatic conditions across the Russian Federation. (Results and discussion) A methodology has been developed to assess the quality of seed material after the storage period, including the justification for the time interval, air mixture temperature parameters and ultraviolet radiation optical modes. The optimal parameters for processing potato tubers, carrots, and beets have been determined. The study examined the impact of ultraviolet exposure with established parameters on the disease development in carrot and beet crops, caused by the studied phytopathogenic microorganisms at temperatures of 2 and 25 degrees Celsius. (Conclusions) The indicators of the spread and development of infectious diseases in the studied vegetable crops show a decline trend when the translational speed of root crop movement is 0.7 meters per second, the interaxial distance between ultraviolet radiation sources is 0.1 meters, the distance from the sources to the roller surface of the conveyor belt is 0.05 meters, and a constant dose of ultraviolet exposure is applied.

Skin cancers are the most frequent cancers in fair-skinned populations, but we can prevent them.

Cancers of the skin are the most commonly occurring cancers in humans. In fair-skinned populations, up to 95% of keratinocyte skin cancers and 70–95% of cutaneous melanomas are caused by ultraviolet radiation and are thus theoretically preventable. Currently, however, there is no comprehensive global advice on practical steps to be taken to reduce the toll of skin cancer. To address this gap, an expert working group comprising clinicians and researchers from Africa, America, Asia, Australia, and Europe, together with learned societies (European Association of Dermato-Oncology, Euromelanoma, Euroskin, European Union of Medical Specialists, and the Melanoma World Society) reviewed the extant evidence and issued the following evidence-based recommendations for photoprotection as a strategy to prevent skin cancer. Fair skinned people, especially children, should minimise their exposure to ultraviolet radiation, and are advised to use protective measures when the UV index is forecast to reach 3 or higher. Protective measures include a combination of seeking shade, physical protection (e.g. clothing, hat, sunglasses), and applying broad-spectrum, SPF 30 + sunscreens to uncovered skin. Intentional exposure to solar ultraviolet radiation for the purpose of sunbathing and tanning is considered an unhealthy behaviour and should be avoided. Similarly, use of solaria and other artificial sources of ultraviolet radiation to encourage tanning should be strongly discouraged, through regulation if necessary. Primary prevention of skin cancer has a positive return on investment. We encourage policymakers to communicate these messages to the general public and promote their wider implementation.

Treatment of polluted water with pesticides by photo-oxidation (Fenton photo)

In this study, advance photo oxidation (Fenton Photo) used to treat some pesticides. Three pesticides were used: spider pesticides (Pyridaben), herbicides (Atlantes), and insecticides (Acetop-20). The ferric sulphate (FeSo4.7H2O) used as oxidant agents, hydrogen peroxide as catalase and sunlight as a source of ultraviolet radiation, TOC and COD tests were used to measure organic matter the variables in treatment are time and pesticide concentration. Removable Effeciency (RE) % of COD are (31.6, 44.1, 46.4) and of TOC test are (63, 58.4, 43.5) at the treatment time (15, 30, 40) minute. According to the findings, treatment duration and pollutant concentration significantly impacted the effectiveness of the removal process.

Water film-mediated photocatalytic oxidation of oxalate on TiO2

Water films on minerals under humid environment can be photocatalytic hotspots when exposed to sunlight or artificial sources of ultraviolet (and visible) radiation. In this study, we resolved the water film-mediated photocatalysis of oxalate adsorbed on TiO2 using in situ infrared spectroscopy. We found that 0.5 to 4 monolayer- (ML) thick water films enhanced the photodecomposition rates of oxalate under 21 kPa O2. We explained this through the combined actions of direct hole transfer, ligand-to-metal-charge transfer, as well as the production of hydroxyl radicals and reactive oxygen species. Rates were, however, substantially slower in the absence of O2 because charge recombination, together with water film-mediated charge localization, disrupted hole transfer and hydroxyl radical production. Our work adds insight into the impact of humidity on controlling important photocatalytic processes in nature (drying soils, atmospheric aerosols), and technology (water and air treatment).

Evaluation of Medical Students’ Knowledge and Their Adherence to Safety Measures Regarding Solar Ultraviolet Exposure

Ultraviolet radiation, a type of electromagnetic radiation, can be released by both artificial and natural sources, including the sun. It is imperative to adopt the appropriate safety measures when close to an ultraviolet radiation source, as unprotected UV radiation exposure has been associated with a higher risk of developing various illnesses, such as skin tumors. This study aims to evaluate undergraduate medical students' knowledge of potential hazards from UV radiation exposure and their practice of safety measures. A cross-sectional study was conducted at Omar Al-Mukhtar University, Al-Beyda City, Libya. One hundred and nine medical students were involved in this study. The questionnaire examined participants' knowledge of and behavior toward potential risks associated with ultraviolet (UV) radiation exposure. Notably, 77.1% of them were female, and 22.9% were male. The majority of the respondents were more than 22 years old. Above half, 59.6% showed moderate knowledge about UV exposure consequences; most of the students, 91%, knew the side effects of UV on health, followed by 86%, who indicated that UV can cause premature aging and cancer. In contrast, less than a third knew that UV has a negative impact on the immune system, and about two-thirds (73.9%) didn't realize that sunburn can occur even on a cloudy day. Although medical students showed a moderate level of knowledge regarding UV radiation, there was a lack of active sun safety measures.

Germicidal efficacy of continuous and pulsed ultraviolet-C radiation on pathogen models and SARS-CoV-2

Ultraviolet radiation’s germicidal efficacy depends on several parameters, including wavelength, radiant exposure, microbial physiology, biological matrices, and surfaces. In this work, several ultraviolet radiation sources (a low-pressure mercury lamp, a KrCl excimer, and four UV LEDs) emitting continuous or pulsed irradiation were compared. The greatest log reductions in E. coli cells and B. subtilis endospores were 4.1 ± 0.2 (18 mJ cm−2) and 4.5 ± 0.1 (42 mJ cm−2) with continuous 222 nm, respectively. The highest MS2 log reduction observed was 2.7 ± 0.1 (277 nm at 3809 mJ cm−2). Log reductions of SARS-CoV-2 with continuous 222 nm and 277 nm were ≥ 3.4 ± 0.7, with 13.3 mJ cm−2 and 60 mJ cm−2, respectively. There was no statistical difference between continuous and pulsed irradiation (0.83–16.7% [222 nm and 277 nm] or 0.83–20% [280 nm] duty rates) on E. coli inactivation. Pulsed 260 nm radiation (0.5% duty rate) at 260 nm yielded significantly greater log reduction for both bacteria than continuous 260 nm radiation. There was no statistical difference in SARS-CoV-2 inactivation between continuous and pulsed 222 nm UV-C radiation and pulsed 277 nm radiation demonstrated greater germicidal efficacy than continuous 277 nm radiation. Greater radiant exposure for all radiation sources was required to inactivate MS2 bacteriophage. Findings demonstrate that pulsed irradiation could be more useful than continuous UV radiation in human-occupied spaces, but threshold limit values should be respected. Pathogen-specific sensitivities, experimental setup, and quantification methods for determining germicidal efficacy remain important factors when optimizing ultraviolet radiation for surface decontamination or other applications.Graphical abstract

Evaluation of Ultraviolet Radiation using the MOORA Method

Ultraviolet Radiation. Non-ionizing radiation emitting manmade sources like the sun and tanning beds includes ultraviolet (UV) radiation. Although it can help humans produce vitamin D and has other advantages, it can also be harmful to their health. The sun is a natural source of UV radiation for us. In industrial processes, as well as in medical and dental procedures, ultraviolet light is frequently used for a variety of purposes, such as the destruction of bacteria, the production of fluorescent effects, the curing of inks and resins, phototherapy, and tanning. Different UV wavelengths and intensities are employed for diverse applications. Using a UV detector is the most secure method of detecting UV radiation. Inform the class that the beads they will be using contain a unique pigment that changes color when exposed to UV radiation. UV detectors are the name of these beads. The UV light around the school can be seen using these. UV radiation is necessary to the body because it promotes the production of vitamin D. In addition to being crucial for bone development, immune system health, and blood cell production, vitamin D increases the absorption of calcium and phosphorus from meals. The three key health benefits of UV light are vitamin D production, enhanced mood, and higher energy. Moderate UV light exposure is a good source of vitamin D. This vitamin helps regulate cell division, insulin synthesis, calcium metabolism, immunity, and blood pressure. History and exploration. Due to violet being the color of the highest frequencies of visible light, the word "ultraviolet" signifies "beyond violet" (Latin ultra, "beyond"). Compared to violet light, ultraviolet has a greater frequency and a shorter wavelength. UV radiation can produce erythema, sunburn, photodamage (photoaging), photosensitivity, eye damage, changes in the skin's immune system, and chemical hypersensitivity depending on the amount and kind of radiation and the type of skin of the individual exposed. -an s-in-the-service-retailer-in-reside-in-the-retail-d-in-star-re-in-main-retail-enterprise type of place. This one. Additionally, UV radiation is produced by sunlamps and tanning beds. The multi-objective optimization by ratio analysis (MOORA) method is one of the MADM techniques. It is a group of qualities (prospective students). It is possible to calculate the worth of criteria, making this the ideal choice for decision-makers like prospective students. Hospital inpatient care, Hospital ambulatory care, Primary health care, Pharmaceuticals, Mortality, Morbidity. Cutaneous Melanoma, Basal Cell Carcinoma, Melanoma in Situ, and Actinic Keratosis. From the result, it is seen that Morbidity got the first rank whereas Primary health care is having the lowest rank.

Germicidal Efficiency of 272 nm LED in Relation to the Hospital Strain of Klebsiella Pneumoniae

Relevance. Currently, the use of ultraviolet (UV) radiation for the disinfection of objects and the treatment for infectious diseases is considered as a promising alternative to chemical biocides and antibiotics. Shortwave — UV-C and UV-B -light emitting diodes (LED) are a relatively new type of UV radiation sources and potentially able to meet the requirements of current medical technologies. However, their possibilities for the treatment of wounds and infectious diseases have not been practically researched to date, which determines the relevance of experiments aimed at studying the biocidal and therapeutic properties of shortwavelength UV LEDs.Purpose. OF STUDY To evaluate the bactericidal efficacy of 272 nm LED radiation against hospital strains of Klebsiella pneumoniae bacteria characterized by multidrug resistance.Materials and Methods. The studies were carried out with an experimental sample of the LED apparatus for UV irradiation. In the irradiator of the device, 5 LEDs are installed with a maximum radiation at a wavelength of 272 nm and a total electrical power of 10 watts. The UV radiation dose achieved in one irradiation session (12 seconds) at a distance of 10 cm from the irradiator was 8 mJ/cm2 . In the experiments, a hospital strain of the bacterium Klebsiella pneumoniae, isolated from the patient’s blood, was used. The strain was characterized by multidrug resistance. A daily culture suspension of K. pneumoniae with a concentration of 108 CFU/ml in a volume of 100 µl was transferred into a Petri dish with a diameter of 9 cm with meat-peptone agar and evenly distributed over a surface with a diameter of 8 cm. Petri dishes were irradiated from a distance of 10 cm from the irradiator. The change in the dose of UV irradiation from 4 to 80 mJ/cm2 was carried out by varying the exposure time. Studies were carried out in 4 repetitions at each dose. After irradiation, the experimental and control (without irradiation) Petri dishes were placed in a thermostat at 37ºC for 24 hours, then the grown colonies were counted. A total of 60 experiments were carried out.Results. As a result of the research, it was shown that the LED device based on five 272 nm diodes provides deep and prompt disinfection of the surface from hospital strains of K. pneumoniae bacteria characterized by multidrug resistance. A dose of UV radiation of 8 mJ/cm2 reduces surface contamination with K. pneumoniae bacteria by more than a million times (decontamination efficiency over 99.9999%). At doses less than 10 mJ/cm2 , the efficiency of the 272 nm LED device in terms of inactivation of K. pneumoniae bacteria is 3–4 times higher than the bactericidal efficiency of mercury lamps.Conclusion.The prospects of using UV devices based on LEDs with a maximum radiation at a wavelength of 272 nm in systems for the operational disinfection of massively contaminated surfaces, potentially including wound surfaces, have been shown.

Anomalous Relativistic Emission from Self-Modulated Plasma Mirrors.

The interaction of intense laser pulses with plasma mirrors has demonstrated the ability to generate high-order harmonics, producing a bright source of extreme ultraviolet (XUV) radiation and attosecond pulses. Here, we report an unexpected transition in this process. We show that the loss of spatiotemporal coherence in the reflected high harmonics can lead to a new regime of highly efficient coherent XUV generation, with an extraordinary property where the radiation is directionally anomalous, propagating parallel to the mirror surface. With analytical calculations and numerical particle-in-cell simulations, we discover that the radiation emission is due to laser-driven oscillations of relativistic electron nanobunches that originate from a plasma surface instability.

Influence of ionization volume and sample gas flow rate on separation power in gas chromatography-ion mobility spectrometry

In this work, the influence of the sample gas flow rate and the ionization region volume of an ion mobility spectrometer (IMS) used as a detector in gas chromatography (GC) on GC-IMS peak shape has been investigated. Therefore, a drift tube IMS with a field-switching ion shutter, a defined ionization region volume and an ultra-violet radiation source was used. To identify the influence of the sample gas flow rate entering the ionization region (equals the GC carrier gas flow rate if no further make-up gas is used) and the ionization region volume on peak broadening and signal intensity, different sample volumes as they would elute from a GC were tested at a variety of sample gas flow rates at a given ionization region volume. The results clearly show that for low sample gas flow rates a depletion of sample molecules in the ionization region leads to a significant decrease in effective detector volume but also to reduced signal intensities. Therefore, for optimal performance of a GC-IMS, the optimal operating point of the GC should match the flow range, where the IMS provides the best compromise between signal-to-noise ratio and peak broadening.

Discharge in a Nonhomogeneous Gas Flow Sustained by Powerful Novosibirsk Free Electron Laser Emission as a Point-Like Source of Vacuum Ultraviolet Radiation

Discharge in a Nonhomogeneous Gas Flow Sustained by Powerful Novosibirsk Free Electron Laser Emission as a Point-Like Source of Vacuum Ultraviolet Radiation

Experiment on the formaldehyde removal performance of TiO2 coating agent for finishing materials

As the frequency of indoor habitation escalates and advancements in building technology optimize airtightness, the importance of maintaining high-quality indoor air has grown increasingly critical. This urgency is further amplified by the proliferation of chemical building materials, necessitating more effective strategies for air pollutant abatement. To address this need, the current study explored the utility of titanium dioxide photocatalysts, which possess chemical decomposition capabilities, as a means of improving air quality within indoor environments. To verify the effectiveness of this approach, the research focused on the removal of formaldehyde—a quintessential indoor air pollutant—by incorporating a titanium dioxide photocatalyst into a coating agent commonly employed in construction materials. Notably, ultraviolet (UV) light, essential for activating the photocatalytic process, is generally absent in indoor settings. To mitigate this limitation, a consistent source of UV radiation was provided through the use of an UV lamp. Adhering to protocols outlined by the International Organization for Standardization, we employed a photoreactor to evaluate the photocatalytic efficiency of the composite material under varying intensities of UV radiation and reactor volumes. The results unequivocally confirmed that variations in UV radiation intensity and reactor volume significantly influenced the photocatalytic effectiveness of the material, resulting in a demonstrable reduction in pollutant concentrations. These findings suggest the feasibility of utilizing titanium dioxide photocatalysts for mitigating outdoor air pollutants, where natural UV radiation is more readily available. However, for indoor applications, the absence of naturally occurring UV radiation presents a considerable challenge. Overcoming this constraint could facilitate the indoor application of photocatalytic coatings, as informed by the optimal conditions of low pollutant reactivity and robust UV radiation revealed in this study, thereby substantially enhancing indoor air quality.

Spatial and temporal evolution of laser plasma produced using a double-stream gas puff target

Laser plasma produced using a double-stream gas puff target is an intense source of soft x-ray (SXR) and extreme ultraviolet (EUV) radiation, however, without the harmful emission of debris associated with a solid target. Debris-free laser plasma x-ray and EUV sources have been applied in many various applications, including metrology, imaging in a nanoscale, tomography, processing materials, emission and absorption spectroscopy, laboratory astrophysics and astrochemistry, radiobiology, and radiochemistry. In this work, the results of the experimental and theoretical studies on the spatial and temporal evolution of laser plasma produced as a result of irradiation of an argon/helium gas puff target with laser pulses of 1.3 or 6 ns time duration generated with an Nd:YAG laser system are presented. Imaging and spectral measurements of SXR emission from the plasma, created in the double-stream gas puff target, have been performed with the use of an x-ray streak camera. The analysis of the results of spectral measurements, supported by numerical simulations of plasma x-ray emission, allowed the estimation of the plasma electron temperature and its changes over time. Experimental data were compared with the results of theoretical studies performed using a computer model of plasma hydrodynamics. It was shown that plasma expansion is fast enough to reduce the plasma density in the laser focus area during the laser–plasma interaction.

Two phase-matching regimes in high-order harmonic generation.

High-order harmonic generation (HHG) provides scalable sources of coherent extreme ultraviolet radiation with pulse duration down to the attosecond time scale. Efficient HHG requires the constructive interplay between microscopic and macroscopic effects in the generation volume, which can be achieved over a large range of experimental parameters from the driving field properties to those of the generating medium. Here, we present a systematic study of the harmonic yield as a function of gas pressure and medium length. Two regimes for optimum yield are identified, supporting the predictions of a recently proposed analytical model. Our observations are independent on the focusing geometry and, to a large extent, on the pulse duration and laser intensity, providing a versatile approach to HHG optimization.

Experimental and theoretical study on the photoionization of styrene.

This study employed a vacuum ultraviolet synchrotron radiation source and reflectron time-of-flight mass spectrometry (TOF-MS) to investigate the photoionization and dissociation of styrene. By analyzing the photoionization mass spectrum and efficiency curve alongside G3B3 theoretical calculations, we determined the ionization energy of the molecular ion, appearance energy of fragment ions, and relevant dissociation pathways. The major ion peaks observed in the photoionization mass spectra of styrene correspond to C8 H8 + , C8 H7 + and C6 H6 + . The ionization energy of styrene is measured as 8.46 ± 0.03 eV, whereas the appearance energies of C8 H7 + and C6 H6 + are found to be 12.42 ± 0.03 and 12.22 ± 0.03 eV, respectively, in agreement with theoretical values. The main channel for the photodissociation of styrene molecular ions is the formation of benzene ions, whereas the dissociation channel that loses hydrogen atoms is the secondary channel. Based on the experimental results and empirical formulas, the required dissociation energies (Ed ) of C8 H7 + , C8 H6 + and C6 H6 + are calculated to be (3.96 ± 0.06), (4.00 ± 0.06) and (3.76 ± 0.06) eV, respectively. Combined with related thermochemical parameters, the standard enthalpies of formations of C8 H8 + , C8 H7 + , C8 H6 + and C6 H6 + are determined to be 964.2, 1346.3, 1350.2 and 1327.0kJ/mol, respectively. Based on the theoretical study, the kinetic factors controlling the styrene dissociation reaction process are determined by using the Rice-Ramsperger-Kassel-Marcus (RRKM) theory. This provides a reference for further research on the atmospheric photooxidation reaction mechanism of styrene in atmospheric and interstellar environments.

Exploding foils with artificial structure as a source of ultraviolet radiation

The results of the study of radiation produced by the electrical explosion of Al foil with a thickness of 4 μm with an artificial periodic structure of periodic holes with 50–400 μm steps created by laser engraving are presented. The experiments were carried out on a KING pulse high-current generator (220 kA, 40 kV, 300 ns). Images of exploded foils were recorded using pinhole cameras with a 20 μm aperture on a four-frame microchannel plate camera with 5 ns temporal resolution. In experiments on the electrical explosion of thin foils, it was shown that the application of an artificial periodic structure to the foil leads to a much more uniform radiation in the UV spectrum range along the entire length and width of the foil. Uniform radiation was observed from 20 to 70 ns. It is shown that such radiation can be used for the imaging of test objects or plasma objects like exploded wires.

Disinfection of Surfaces Contaminated with SARS-CoV-2 Coronavirus by UV Radiation of Low-Pressure Mercury-Vapour Lamp

The aim of the work was to determine the effective ultraviolet (UV) doses required for the disinfection of surfaces contaminated with the SARS-CoV-2 coronavirus using a low-pressure mercury lamp. Materials and methods. To carry out prompt disinfection of surfaces, a specially designed source of UV radiation with a power of 7.5 W at a wavelength of 254 nm in the form of a portable flashlight was employed, which has a high efficiency of UV radiation output and the possibility of long-term autonomous operation from a compact battery. In the studies, a suspension culture of the SARS-CoV-2 coronavirus with biological activity of 5.3∙106 PFU/ml was used. The objects of testing were plastic Petri dishes (disposable) and office paper (grade C, density 80 g/m2 ). Results and discussion. Doses of UV radiation that provide disinfection of surfaces contaminated with the COVID-19 pathogen with an efficiency of 99.0 % (paper) to 99.95 % (plastic) have been determined. The results obtained make it possible to recommend a portable UV irradiator for use in the practice of preventive measures to combat the spread of the disease caused by the SARS-CoV-2 coronavirus.

Study of the Sensor Properties of Ordered ZnO Nanorod Arrays for the Detection of UV Radiation

Zinc oxide is one of the most promising materials used to create devices in the ultraviolet (UV) range. In this article, we study the sensor properties of ordered ZnO nanorod arrays grown by chemical vapor deposition. The possibility of their use as an indicator of UV radiation to control the dose of UV radiation, both from natural and artificial light sources, is assessed. The X-ray diffraction, Raman spectroscopy (RS), and cathodoluminescence (CL) data demonstrate the high quality of nanorods. Based on the ZnO nanorod array, a sensor prototype was fabricated based on the change in ZnO conductivity under the UV irradiation. A compari-son of the response of such a sensor with the readings of a UV radiometer showed a high correlation.

Determining the efficiency of using led sources of ultraviolet radiation for ionization and disinfection of room air

This paper reports a study into the possibility of using LED systems of ultraviolet radiation for air ionization and disinfection of air and indoor surfaces in the presence of people. It has been established that UV LED lamps with 120° opening angles have parameters under which radiation intensity does not exceed 30 J/m2 at distances of 2 meters. Based on experimental data, a methodology for designing the placement of lamps in the room was devised, which meets the requirements of the SBM-2015 standard and the European Directive 2006/25/EU. The use of LED emitters with a total intensity of up to 25 J/m2 increases the concentration of aero ions. The background concentrations were 140‒180 cm-3 (positive) and 160‒190 cm-3 (negative). The minimum permissible level is 500 cm-3. As a result of irradiation, the concentrations were 1100‒1460 cm-3 (positive) and 1260‒1470 cm-3 (negative). The influence of the recirculator-air purifier on the concentration of aero ions has not been established. The ionization process began immediately after turning on the irradiation systems in the entire volume of the premises (4‒5 meters from the source). The dynamic equilibrium of aero ion concentrations was established within 10‒15 minutes after the irradiation was switched on. The presence of a large number of people (up to 0.97 m2 per person) did not affect the concentration of aero ions. Under the combined effect of ultraviolet radiation and a recirculator-air purifier, the number of mold fungi colonies decreased by 20 times. Under the influence of only ultraviolet radiation – by 2.3 times. The decrease in the number of microbes under the combined effect was 1.6 times, and under the effect of only ultraviolet radiation – 2.8 times