Personal Respiratory Protection Research Articles

АНАЛИЗ НАДЕЖНОСТИ СРЕДСТВ ИНДИВИДУАЛЬНОЙ ЗАЩИТЫ ОРГАНОВ ДЫХАНИЯ ПОЖАРНЫХ

The article examines the analysis of the equipment of fire and rescue units of the Ministry of Emergency Situations of Russia in the Vladimir region with personal respiratory and visual protection equipment for firefighters. The statistics of their failures are presented, as well as the process of determining the most unreliable elements of the personal respiratory and visual protection equipment for firefighters, as well as an analysis of the causes of failures. It was determined that the main reasons for the failures of the personal respiratory and visual protection equipment for firefighters are a decrease in the reliability of the functional elements of the pulmonary automaton: a violation of the tightness of the housing, incomplete switching on/off of the additional air supply button (bypass) due to mechanical action on the actuator (springs, membranes), a change in the shape and chemical composition of plastic elements. It is shown that a significant number of negative factors affect the reliability of the personal respiratory and visual protection equipment for firefighters. The results of the study will be useful for both responding fire and rescue units and manufacturers of personal respiratory and visual protection equipment for firefighters in terms of forecasting and monitoring the reliability of their elements. In practice, this will increase the safety and efficiency of fire protection units in an inhospitable environment.

Determination of the Convergence of Intra-Laboratory Measurements of Dust Content on a Construction Site

Introduction. Intra-laboratory comparison tests play an important role in ensuring the quality and reliability of research outcomes in laboratories. These tests allow researchers to evaluate the accuracy and reproducibility of the methods they use in their work, as well as to identify potential sources of error and inconsistency. The results of these tests are shared with experts to confirm competence within the accreditation. Typically, comparison tests are carried out in laboratory conditions in a familiar and calm environment for the testers. However, when laboratories conduct research as part of a special assessment of working conditions (SAWC) they are required to conduct on-site comparisons at real-world facilities, where customers may unwittingly disrupt the process and directly affecting the quality of the measurements. The aim of this study is to evaluate the quality of on-site intra-laboratory comparison tests using the example of determining the dust content in a bricklayer's work environment on a construction site, and to determine the minimum number of measurements necessary and sufficient for this purpose.Materials and Methods. To determine the dustiness of the bricklayer's workplace, a weighing method was used. This involved collecting dust on filters and then weighing them to determine the concentration. The quality assessment of intra-laboratory tests was conducted in accordance with GOST R ISO 5725-1-2002 "Accuracy (trueness and precision) of measurement methods and results. Part 1. General principles and definitions".Results. At the bricklayer's workplace, a 1.6-fold excess of the one-time maximum permissible dust concentration was detected. The average dust concentration at the workplace under study was: Kp2 = 9.57 ± 0.81 mg/m3, the convergence of the results obtained was r = 8.68 %, the relative error δ = 8.50 %. It was revealed that the maximum allowable difference between the results of the two tests was 0.84 mg/m3. The difference in direct measurements of the mass of the two samples should be no more than 0.1 mg.Discussion and Conclusion. The results obtained demonstrated the possibility of conducting a minimum number of measurements that, under reproducible conditions, are considered satisfactory and could be provided to experts for confirming the competence of the laboratory. As part of a special assessment of working conditions, employees of the object under study are recommended to use personal respiratory protection equipment that offers protection against highly dispersed dust particles.

Re-inventing protection in a post-pandemic world: A new aerodynamic endonasal filtration technology

Is there a “missing device” for respiratory personal protection? Does it exist an easy-to-use device, allowing extensive use in everyday settings by the population, maximizing tolerability and low visual and physical invasiveness protecting from a wide range of threats including airborne pathogens, hence including the particle range of fine and ultrafine particles? Looking at the recent past, in the urgency of finding ready-to-use solutions for the respiratory protection of the population during the outbreak of the SARS-CoV-2 pandemic, devices for occupational safety have been used, such as filtering face masks. These are devices intended for workers operating during work shifts in environments characterized by potential high risk, known a priori, often directly sensible; this makes wearers motivated to tolerate discomfort for a given period to face a localized risk, and safety managers determined to supervise compliance with usage specifications. Their use by general population has implied known shortcomings, such as weak compatibility with relational work and activities, low tolerability during prolonged use, low compliance with the proper use of the device, all of this lessening actual protection. The need for a new perspective has emerged, targeting effectiveness in whole daily life, rather than punctual efficacy. Nasal filters are promising candidates to protect individuals throughout the day during the most varied activities, but they lack a systematic definition as a device and as a product; it follows that the high complexity needed to reach an effective performance envelop is generally underestimated. By reviewing available literature, the present paper draws on the experience from the pandemic and infers systematic product specifications and characterization methods for a new, effective personal respiratory protection device; these specifications are compared with the stringent constraints associated with the endonasal applications and, based on air filtration state of the art, quantifies the need for technology disruption and outlining possible new development paths.

MINIMISATION OF THE NEGATIVE EFFECTS OF EXPOSURE TO OF THE IMPACT OF INCENDIARY WEAPONS ON THE CIVILIAN POPULATION

Incendiary weapons are understood as incendiary substances and means of their combat use. Incendiary weapons are intended to defeat personnel, destroy and damage weapons and military equipment, structures and other objects. Throughout the history of warfare, incendiary weapons have caused suffering to millions of people who were not directly involved in the armed conflict. The situation remains unchanged today, with civilians being killed, injured or disabled for life, often losing loved ones or property as a result of the use of incendiary weapons. Virtually all existing publications on protecting people from incendiary weapons are focused on the protection of military personnel. There is very little information on how to protect civilians.
 An algorithm of actions for a civilian to minimise the negative effects of the impact of incendiary weapons has been developed. This algorithm includes the following actions: timely warn others about the use of incendiary weapons, help and, if necessary, guide the actions of those who need it (elderly people, children, people in panic); take shelter in the nearest civil defence structure, shelter (shelter). In the absence of such facilities, use underground passages, subway stations, basements and entrances of residential buildings, and shops; in the event of a sudden attack and the absence of nearby civil defence structures, shelters and refuges, use the protective properties of vehicles. It should be borne in mind that cars, buses and vehicles covered with tents provide only short-term protection, as they quickly catch fire.
 Use the protective properties of the terrain (uneven terrain, pits, covered public transport stops, fences, benches, curbs) to reduce the chance of pieces of incendiary material falling on a person; if it is impossible to find any shelter, lie down on the ground. Use local materials available to protect the surface of the body from incendiary weapons (suitcases, backpacks, billboards, paper clips). Burning surfaces are immediately thrown off and extinguished. Use personal respiratory protection equipment (handkerchiefs soaked in liquid, pieces of cloth) and skin protection equipment (cotton jackets, half-coats, raincoats, which are short-term protection equipment and should be immediately discarded if they come in contact with pieces of incendiary mixture); provide first aid to the victims. First aid shall begin with extinguishing by the victims themselves or with the help of surrounding inflammable substances that have got on their skin or clothing. At this point (period), no loss of self-control is allowed. To extinguish a small amount of inflammable substance, it is necessary to cover the burning area with a sleeve, jacket, wet clay, earth or snow. If several pieces of clothing are burning on your person, the flames should be knocked down by rolling them successively on the ground.
 If a significant amount of inflammable substance gets on a person, extinguishing is carried out by covering the victim with clothes, pouring water, covering with earth or sand.

Health effects of filtering facepiece respirators: Research and clinical implications of comfort, thermal, skin, psychologic, and workplace effects.

Filtering facepiece respirators (FFR's) such as N95s have become widely used in appropriate settings for personal respiratory protection and are increasingly used beyond workplace settings. Concerns about possible adverse effects have appeared in many publications, particularly since the COVID-19 pandemic led to much more widespread use. This paper synthesizes known effects based upon review of publications in PubMed since 1995, addressing effects other than pulmonary and cardiovascular (reviewed elsewhere). Findings: (1) Subjective discomfort is very frequently reported; this includes general discomfort or organ-system-specific complaints such as respiratory, headache, dermatologic, and heat. Research methods are widely divergent, and we propose a taxonomy to classify such studies by methodology, study population (subjects, experimental vs. observational methodology, comparator, specificity, and timeframe) to facilitate synthesis. (2) Objective measures of increased heat and humidity within the mask are well documented. (3) Frequency and characteristics of dermatologic effects have been insufficiently evaluated. (4) Physical mask designs are varied, making generalizations challenging. (5) More studies of impact on work performance and communication are needed. (6) Studies of effect of FFR design and accompanying training materials on ease and consistency of use are needed.

Расчетная оценка эффективности технических решений по естественному проветриванию обычных лестничных клеток при пожаре в жилых зданиях

Introduction. Natural ventilation of ordinary staircases in case of fire is provided for by the provisions of regulatory documents in the field of fire safety and plays an essential role in ensuring the safety of people. This article analyzes the effectiveness of ventilation of staircases through window openings in the outer walls, as well as through the openings of exits to the roof. The purpose of this article is to develop criteria and mathematical relationships for evaluating the effectiveness of technical solutions for ventilation of staircases, as well as their approbation for residential buildings of various heights. Methods. Mathematical methods are used to predict the concentration of combustion products on different floors of stairwells, depending on the area of open window openings and the possibility of opening roof access hatches, as well as an analytical method for evaluating the effectiveness of technical solutions for ventilation of stairwells. Resu lts. Theoretical provisions have been developed to assess the effect of the area of open window openings and roof hatches on the natural ventilation of ordinary staircases in sectional-type residential buildings with exits from apartments to staircases, and calculations have been made to evaluate the effectiveness of these solutions in buildings of various heights. Conclusions. Based on the research, criteria and mathematical ratios have been developed to evaluate the effectiveness of various technical solutions for the natural ventilation of ordinary staircases. At the same time, the effectiveness of these solutions is determined by the possibility of rescuing people from the apartments of the corresponding floor without the involvement of a significant number of firefighters and without the use of personal respiratory and eye protection equipment.

Разработка фильтрующе-сорбирующих материалов в целях формирования ассортимента современных фильтров для противогазов и респираторов

The article focuses on the study of filter-sorbing materials (FSM) for the development of small-sized filters and the formation of a modern filters range for gas masks and respirators. There are various kinds of filters, namely particle filters, consisting of a filter material (FM) with protection from aerosols; gas filters, consisting of coal charge with protection from various concentrations of dangerous gases and vapors and combined filters, including anti-aerosol and gas protection. But in industry, due to the improvement of working conditions at enterprises, personal respiratory protection equipment is needed both from aerosols and from low concentrations of dangerous gases and vapors in the air of the working area. The creation of a new small-sized filter with a single filter-sorbing element with low resistance to air flow during breathing is an actual task. In order to form an assortment of modern filters for gas masks and respirators, we studied FSM in the form of polymer or glass fibers sprayed with carbon particles. An experimental series of studies based on the use of FSMs with adsorbents has been carried out, activated carbon (AC) and various absorbers were obtained by impregnation of AC. It is determined that the impregnation of AC with special additives allows for additional protection from inorganic and acid gases and vapors, from ammonia. Comparative tests of the FSMs were carried out with the analysis of the research results. Optimal FSMs have been determined. The fractional composition of coal particles is determined depending on the method of their application. The sorption properties of the obtained FSMs are determined. In this work, for the first time, the combination of a filter material with AC impregnated with chemical additives in particle filters was tested and evaluated. The effect of a combination of AC and a fibrous semi-finished product on the properties of FSM has been studied.

КАЧЕСТВО И ТОВАРЫ МАССОВОГО ПОТРЕБЛЕНИЯ В ПОЗДНЕСОВЕТСКОМ ОБЩЕСТВЕ

The paper analyzes the content and meaning of the concept of “quality” in the late USSR at the level of political discourse and among scientists. Based on selected cases of the history of Soviet materiality – personal respiratory protection equipment, foodstuffs and clothing – the peculiarities of the definition of quality as an economic, scientific, technological and cultural category are examined. After the Great Patriotic War, quality was an important category in Soviet industrial production and the scientific and industrial sector. In industrial and political discourse, quality acted as an important category of modernity, generally denoting modern society. It meant the increased importance for the state of the quality of life and the categories of life safety and working conditions of the Soviet person and was at the center of the rhetoric about the material basis of communism. Science and the notions of the wide possibilities of scientific tools in the production of wholesome foodstuffs and comfortable and high-quality clothing played an important role in the evolution of the notion of “quality” in the late Soviet period. In addition, in the last decades of the Soviet era, quality was also associated with the notion of safety in a broad sense. It meant the possibility of producing and consuming goods and food products that are safe for consumption. The article also shows the significance of Soviet quality in contemporary Russia in the context of the phenomenon of nostalgia for the Soviet. This study thus allows the author to contribute to the study of the history of Soviet everyday life, material history, as well as the history of economic development of the USSR.

COMPARATIVE ASSESSMENT OF BACTERIAL PERMEABILITY OF A PERSONAL PROTECTIVE RESPIRATORY EQUIPMENT AT DIFFERENT DURATIONS OF ITS CONTINUOUS OPERATION.

The aim: To establish the level of antibacterial protection of the studied personal protective respiratory equipment set and its main components and compare antibacterial resistance of the personal protective respiratory equipment set in the presence and absence of filtering components. Materials and methods: The proposed methodology for assessing biological protection parameters is based on testing the permeability of personal respiratory protection equipment for bacteria by the method of serial dilutions. Also additional culturing of separate components of the protective set on a separate media is carried out. The experiment was also repeated in the absence of filtering elements and when they were replaced by gauze masks. Results: The use of a fully equipped pneumatic helmet counteracted the penetration of the bacterial aerosol, which was manifested in the absence of growth on the media. The results obtained with the full configuration, as well as the indicators of the spread of bacteria when removing the filter elements and replacing them with gauze masks, showed that the device creates sufficient positive air pressure inside. The latter becomes a restraining factor that does not allow microorganisms to penetrate through the lower circuit. Conclusions: Increasing the duration of continuous operation of the conceptual model up to 24 hours, increasing the bacterial load on the filters do not lead to a deterioration in the properties of antibacterial protection. Bacterial aerosol did not penetrate into the inner space of pneumatic helmet.

Проблемные вопросы тепловой защиты средств индивидуальной защиты органов дыхания и зрения пожарных

Temperature of the inhaled gaseous medium in fires is an important parameter of personal respiratory and eye protection equipment, however, the national standards do not regulate the temperature inside their front part. The main criterion considered during testing is the ability of the device to protect the user from toxic combustion products. According to the requirements of national standards, the tests are aimed at assessing the resistance of one unit of the product to one of the types of temperature effects (heat flow, open flame) within the framework of one conducted test. At the same time, the temperature inside the front part and components of breathing apparatus is not recorded and monitored, as well as the effect of thermal fire factors on personal respiratory and vision protection equipment and their components. Unlike the national standards, NFPA standard implies a comprehensive test to verify the protective properties of breathing apparatus with compressed air under the combined influence of various thermal factors. In this situation, it is advisable to propose the following measures: temperature measurement at the most critical points of the internal space of the front part and housings of breathing apparatus with compressed oxygen and breathing apparatus with compressed air; comprehensive testing of the combined effect of thermal factors on all the structural elements of personal respiratory and vision protection equipment. Thus, testing of personal protective equipment for respiratory and vision organs should be carried out under conditions of the combined exposure to thermal factors with variable values of the heat flux and exposure time, as well as considering the time of the protective action of personal protective equipment. This will provide an opportunity to assess the protective properties of personal protective equipment for organs under all types of thermal exposure, and update regulatory documents aimed at standardization in the field of application of personal protective equipment for respiratory and vision organs.

A simple surgical mask modification to pass N95 respirator-equivalent fit testing standards during the COVID-19 pandemic

BackgroundThe COVID-19 pandemic has infected hundreds of millions of people resulting in millions of deaths worldwide. While N95 respirators remain the gold standard as personal protective equipment, they are resource-intensive to produce and obtain. Surgical masks, easier to produce and obtain, filter ≥95% submicron particles but are less protective due to a lack of seal around a user’s face. This study tested the ability of a simple surgical mask modification using rubber bands to create a seal against particle exposure that would pass N95 standards.Methods and findingsForty healthcare workers underwent TSI PortaCount mask fit testing using an ASTM Level 1 surgical mask modified with rubber bands. Fit Factor was determined after testing four standard OSHA N95 fit testing scenarios. Performance of the properly-modified surgical mask was compared to that of a poorly-modified surgical mask, an unmodified standard surgical mask, and an N95 respirator. Thirty-one of forty (78%) healthcare workers passed Fit Factor testing using a properly-modified mask. The Fit Factor success rate significantly improved by subsequent test date (p = 0.043), but was not associated with any other participant characteristics. The average Fit Factor score for the properly-modified mask was 151 (SD 65.2), a significantly better fit than the unmodified mask score of 3.8 (SD 3.1, p<0.001) and the poorly-modified mask score of 24.6 (SD 48.4, p<0.001) but significantly lower than a properly fitted N95 score of 199 (SD 4.5, p<0.001).do.ConclusionsRubber bands, a low-cost and easily-accessible modification, can improve the seal and protective ability of a standard surgical mask to the level of an N95 respirator. This could mitigate N95 respirator shortages worldwide and provide individuals in under-resourced regions a practical means for increased personal respiratory protection.

Research and manufacture toxic gas filter materials on the basis of activated carbon impregnated with additives used in the manufacture of fire escape masks

This paper presents the results of research and fabrication of a layer of material that adsorbs some toxic gases that stimulate acidic respiration and the smoke and dust generated by the fire. Methods used: SEM- EDS; determining the BET surface area; the protection time with benzene and HCl vapor on the dynamic adsorption device DPC5... The results showed that the additively impregnated activated carbon cloth filter material has a specific surface area in BET of 697 m2 /g, has a protection time against benzene vapor of 34 minutes; protection time with HCl acid vapor is 33 minutes and the ability to filter smoke particles reached 94%. The filter material made from coconut shell activated carbon has a surface area calculated according to BET being 664 m2/g, has a protection time with benzene vapor (L= 5 cm, Co = 18 mg/L) of 56 minutes; protection time with HCl acid vapor (L= 5 cm, Co= 1.1 mg/L) is 280 minutes. Construction of Xylop curve determines the ability to filter benzene vapor and the ability to filter HCl acid vapor shows. This material has potential for the use in the manufacture of personal respiratory protection and environmental remediation.

The influence of age, waist circumference and smoking on the respiratory function indices on the example of employees of a chrome ore mine

Introduction. Employees engaged in mining are exposed to several harmful (hazardous) occupation factors: dust factor, industrial noise, general and local vibration, hard labour, heating or cooling microclimate. The paper aims at studying the influence of the length of employment in underground chrome ore mining coupled with biological (age, obesity) and behavioral (smoking) parameters on spirometric bronchial obstruction indices. Material and methods. The study included 134 employees of a chrome ore mine having underground experience from 1 to 33 years. The comparison group comprised of 404 people who had never worked in a mine. External respiration function was evaluated using the Spirometer SP-1 (Schiller). Statistical processing was carried out using the SPSS 22. One-factor and multi-factor linear regression models were built. Results. The construction of one-factor linear regression models of the dependence of FEV1%, FVC% considering the selected independent factors (age, waist circumference, smoking experience, underground experience) showed a statistically significant effect on the dependent variable of all factors in the model (R2 = 0.010-0.135; p = 0.026-0.0001). The variability of obstructive parameters in a multi-factor linear regression model occurs not often in terms of the studied factors (as for FEV1%, R2 = 0.163; as for FVC%, R2 = 0.107). Smoking experience and waist circumference are the most significant factors leading to the decrease in these indices. Age and underground work experience are less important, but statistically significant. Limitations. The limitation of the results of the study was that they characterize a specific set of certain working conditions and lifestyles of workers in chromium mines. Conclusion. A small part of the impact on the obstruction indices of underground work experience might be due to the use of modern engineering systems to eliminate the harmful effects of occupation factors, as well as personal respiratory protection from dust exposure.

Features of direct measurements for evaluation of the volume activity of radionuclides in the air of the working area

OBJECT. To consider problematic issues related to measurements of radionuclides in the air of the working area released during repackaging of bulk solid radioactive waste during decommissioning of nuclear energy facilities. To develop a method of direct measurements for operational control of the concentration of radioactive aerosols in the air of the working area, ensuring that the control level is not exceeded by the annual effective dose of personnel.METHODS. To solve this problem, the method of calculating the maximum possible number of alpha particles on the selected sample of the analytical filter AFA-RSP20 was used.RESULTS. A method of operational control of the radiation situation in the workplaces of personnel using direct measurements by portable radiation monitoring devices of the alpha particle flux density from the exposed AFA-RSP20 filter is proposed. The use of this method makes it possible to provide control in cases where the use of standard installations for measuring the volumetric activity of radioactive aerosols is unavailable or impossible. The article describes the relevance of the topic, the calculation of the reference level of the alpha particle flux density from the surface of the AFA-RSP20 filter is given.CONCLUSIONS. Passport characteristics of personal respiratory protection equipment do not provide convincing data on the operation of the filter with a specific pollutant. For the correct decision-making on the use of certain types of personal respiratory protection by personnel working with radioactive waste containing transuranium radionuclides, it is necessary to control the volumetric activity of radionuclides in the air. Based on calculations and direct measurements, it is shown that the use of an operational method for measuring the alpha particle flux density from an exposed AFA-RSP20 filter makes it possible to monitor the radiation situation at personnel workplaces during decommissioning of nuclear energy facilities.

Research and fabrication of toxic filter materials from Tra Bac coconut shell activated carbon applied in the manufacture of personal respiratory protection devices

This paper presents the results of research on making materials to adsorb toxic acidic gases, organic substances from Tra Bac coconut shell activated carbon, and combined with chemical treatment on the laboratory scale. Methods were used for this study consisting of SEM, EDS; BET, and DPC5 (kinetic adsorbent). The results showed that the fabricated filter material has a surface area of 664 m2/g, calculated according to BET, has a protection time with benzene vapor (L= 5 cm, Co(vapor) = 18 mg/L) of 56 minutes; protection time with HCl acid vapor (L= 5 cm, Co (vapor) = 1.1 mg/L) is 280 minutes. The results of the study have exhibited a good ability to filter benzene vapor and HCl vapor. This material has the potential for use in the manufacture of personal respiratory protective equipment.

MONO- AND BIFUNCTIONAL IMPREGNATED FIBER CHEMOSORBENTS FOR RESPIRATORY PURPOSE

This paper summarizes the data on the development of import-substituting impregnated This paper summarizes the data on the development of import-substituting impregnated fibrous chemisorbents (IFCS) intended for equipping gas cleaning equipment and personal respiratory protection equipment against gaseous toxicants of various chemical nature. To obtain IFCS of the basic gases (ammonia, organic amines), aqueous solutions of polybasic acids (citric, tartaric and hydroxyethylenediphosphonic) are used as impregnating reagents. IFCS absorb toxicants due to neutralization reactions. The absorption of ammonia and amines of IFCS obtained by impregnation of fibrous carriers (FC) with aqueous solutions of 3d-metals (Ni2+, Co2+ and Cu2+) salts occurs due to complex formation reactions. To obtain IFCS of acidic gases, aqueous solutions of sodium carbonate and urotropine (HMTA) containing structuring additives were used. Impregnating aqueous solutions based on monoethanolamine (MEA) and polyethylenepolyamine (PEPA) have also been developed using their non-volatile derivatives with a higher molar mass. A significant improvement of the IFCS protective characteristics was achieved by introducing of various modifying additives – promoters into the composition of these solutions. Single-layer IFCS -ampholytes (IFCS-A) for respiratory purposes have been developed, which depending on the circumstances are able to absorb both acidic and basic gases (vapours), for example SO2 and NH3. Impregnation solutions include complex compounds of 3d-metals (Ni2+, Co2+ and Cu2+) with MEA, ethylenediamine, HMTA and PEPA at various molar ratios of components or buffer mixtures based on polybasic acids and organic bases (MEA and PEPA) of medium strength salts. Chemisorbents for acidic and/or basic gases (IFCS-I, IFCS-AI) have been developed, the moment of “response” of the dynamic absorption capacity of which can be visually determined by the change in color of the gas mask elements during the “breakthrough” of the sorbate, obtained by impregnating of FC with solutions containing acid-base indicators.

Influence of Seasons and Sites on Bioaerosols in Indoor Wastewater Treatment Plants and Proposal for Air Quality Indicators

During wastewater treatment, bioaerosols are generated and, can either remain in suspension for several hours or settle on surfaces and workers may be exposed. The presence of pathogens in the air could contribute to an increased frequency of gastrointestinal or respiratory illness amongst workers. Due to harsh winter conditions in Eastern Canada, much of the steps in the wastewater treatment process occur indoors, leading to a greater risk of significant occupational exposure especially if there is inadequate ventilation or a lack of personal protection. This work has used stationary sampling at various indoor wastewater treatment steps in both winter and summer. Bioaerosols were evaluated using both culture and molecular methods along with ventilation characterization. Endotoxins were quantified, as well as total cultivable and Gram-negative bacteria and pathogen indicators using qPCR. This study highlights the presence of potential pathogens at all steps in the treatment process, which may represent a potential occupational hazard. Comparisons between summer and winter data suggest that water temperature is an important factor for microbial activity and suggest that increasing the rate of air changes per hour in summer would be beneficial to reduce the concentration of bioaerosols during this time of the year. The screening, grit/FOGs removal and biofiltration were the most bioaerosols loaded sites. Based on strong correlations, we suggest the reconsideration of exposure limits in WWTPs. Workers should be encouraged to use personal respiratory protection to limit the risk of health problems, especially during long-term work. Implication Statement The work presented herein showcases significant correlations between concentrations of endotoxins, cultivable bacteria, Gram-negative bacteria, and total bacteria by qPCR from air collected in indoor wastewater treatment plants. These correlations lead us to propose new Limit of Exposure values, revisited to fit the Endotoxin exposure limits recommendations. The results can serve as guidelines for future proposals for air quality indicators.

Outbreak of Silicosis in Workers Producing Artificial Stone Skirting Boards: A Novel Application of Silica-Based Composites

Outbreak of Silicosis in Workers Producing Artificial Stone Skirting Boards: A Novel Application of Silica-Based Composites

Respirator cartridge change schedule (literature review)

Introduction. A necessary condition for protecting an employee from gases with the help of filtering personal respiratory protection equipment (PPE) is the timely replacement of filters. Previously, the reaction of the sense organs to the ingress of gas into the mask was used for this. Due to unreliability, this method has been completely banned in all developed countries, since filter life is estimated under the worst expected conditions for scheduling filter replacement. Materials and methods. We prepared the article using publications NIOSH, OSHA, Taylor &amp; Francis, Springer, Journal of the ISRP, legal requirements of developed countries for the use of respirators, and other available publications. Results. The article describes problems and ways to solve them during scheduling, using mathematical modeling of the service life (single use of the filter), taking into account its advantages and disadvantages and problems in assessing the safety of reuse of cartridges. Conclusion. The article contains an analysis of the sources of risk for workers using gas masks in Russian Federation; recommendations for its reduction are given.

УДОСКОНАЛЕННЯ ПРОЦЕДУРИ ВИБОРУ ФІЛЬТРУВАЛЬНИХ ПРОТИПИЛОВИХ РЕСПІРАТОРІВ НА ОСНОВІ ОЦІНКИ РИЗИКІВ

Purpose. The improvement of the procedure for selection of dust filter respirators with taking into account the risks in the workplace. Methodology. To determine the best method for risk assessment, the review of scientific publications has been done; the scientific works that have been conducted on the problem by some institutes of hygiene in recent years, have also been studied; discussions on improving the operating conditions of respirators with scientists from the institutes of occupational health and specialists in labor protection of industrial enterprises of the coal industry have been held. Results. The procedure for the selection of dust filter respirators, which consists of three main steps, has been developed. This allows taking into account the whole set of influential factors of the production environment when assessing the risk and choice of personal respiratory protection. It differs from the existing ones in the ability to take into account operational risks that increase the intensity of work, which can affect the physical health of the user. To assess the operational risks, it has been proposed to use five main indicators of dust filter respirators: duration of work, limitation of the field of view, resistance to respiration, weight, and CO2 content. The main types of errors in the selection and operation of dust filter respirators have been identified. It can significantly reduce the effectiveness of protection of respirator users. Scientific novelty. It is a scientific basis for the procedure for selecting dust filter respirators based on an assessment of operational risks to workers, taking into account the impact of environmental factors that can lead to errors in the choice and operation of personal respiratory protection. Practical significance. Recommendations for the selection of dust filter respirators based on risk assessment have been developed. Risk assessment includes the following main steps: identification of the harmful factor, determination of the type of hazard to the worker and calculation of operational risk, as well as selection and justification of the protective device model. In addition, some typical errors in the selection and operation of personal respiratory protection means have been described, which can significantly impair the level of protection of users. Recommendations for assessing the operational risks of dust filter respirators, which increase the intensity of work, have also been worked out.