Justification of measures to protect against exposure nicotine-containing products in enclosed spaces

Introduction. The introduction of amendments and additions to the anti-smoking Federal Law No. 15-FZ of 23.02.2013 in 2020 contributed to the cardinal revision of the name of this law and the introduction of a ban on consumption of any nicotine-containing products in public places. There are no separate, specially allocated isolated premises provided for the consumption of tobacco products and other types of nicotine-containing products by law, even though specially conducted studies have shown significantly different levels of additional inhalation risk arising from air pollution when consuming tobacco products and electronic nicotine delivery systems or heating tobacco. The aim of the study: based on experimental data, to justify the multiplicity of air exchange in unique isolated rooms designed to protect against the effects of ambient tobacco smoke, the consequences of tobacco consumption or nicotine-containing products. Materials and methods. The study was subject to 3 types of nicotine-containing products: tobacco cigarettes (cigarettes), an electronic nicotine delivery system (ENDS) and an electronic tobacco heating system (ETHS). In the course of the study were carried out: a series of experiments on the consumption of nicotine-containing products in various ways in a specially equipped indoor room, air sampling and laboratory studies were performed, the gross and specific emissions of chemicals entering the air environment from one unit of production per hour were calculated, the selection of priority chemicals for calculating the air removed from the room when using nicotine-containing products of each type was carried out, the necessary level of air exchange of premises was calculated, intended for the consumption of tobacco or nicotine. Results. The indoor air quality assessment showed that the main components of the gross intake into the air environment are suspended particles and carbon monoxide when smoking cigarettes. However, taking into account the values of the maximum permissible concentrations, the most significant contribution to the integral indicator is made by acetaldehyde and suspended particles PM10 and PM2.5. Using ENDS, the most significant pollutants were acetaldehyde and carbon monoxide, using ETHS - acetaldehyde and suspended particles PM10 and PM2.5. For all the investigation types of products, the priority substance for calculating the removed air is acetaldehyde, its share in the structure of all detected pollutants was: for cigarettes - 56.27%, for ENDS - 62.7%, for ETHS - 82.51%, in connection with which its specific values can be used to calculate the consumption of the removed air when modelling a specially allocated room intended for the consumption of tobacco products and other types of nicotine-containing products. Conclusion. The obtained findings demonstrated an obvious, more than 10-fold difference in the requirements for air exchange of premises intended for cigarette smoking and premises intended for the consumption of ENDS or ETHS, at the same intensity of consumption. Therefore, when organizing specially designated places for smoking or the consumption of nicotine-containing products, it is advisable to separate them depending on the type of products consumed: tobacco smoking separately, ENDS and ETHS consumption separately.

THE RESEARCH THE INFILTRATION EFFECT OF OUTSIDE AIR ON THE VALUE OF AIR EXCHANGE IN LOW-RISE RESIDENTIAL BUILDINGS

This article presents the results of a theoretical study of the infl uence the outside air infi ltration through the enclosing structures of the walls on the amount the air’s exchange in low-rise residential buildings. Based on the information analysis from offi cial documents of state statistical and analytical bodies, the most frequently used external wall structures in modern low-rise residential construction have been determined. Based on the provisions analysis of modern regulatory documents in the construction’s fi eld, the minimum values the required air exchange were determined and the calculations of the values the infi ltration air fl ow through the outer walls for various premises of low-rise residential buildings were made. Based on the results of the analysis and calculations was made a generalizing conclusion that for the considered premises of modern low-rise residential buildings, at the expense of the infi ltration of outside air through the enclosing structures of the walls, it is impossible to provide even 20 % of the minimum air exchange.

CFD Study on the Ventilation Effectiveness in a Public Toilet under Three Ventilation Methods

The indoor air quality (IAQ) of severely polluted toilets is associated with the transmission of diseases. Computational fluid dynamics (CFD) methods and experimental measurements were used to analyze the diffusion characteristics of pollutants. This study investigated the diffusion characteristics and normalized concentration of ammonia and hydrogen sulfide pollutants under three ventilation systems—mixing ventilation (MV), personalized ventilation (PV), and impinging jet ventilation (IJV)—in a public toilet. The mean age of air (MAA) and air exchange efficiency (AEE) were also analyzed in our study. The results show that the MV scheme has a poor removal effect on pollutants compared with PV and IJV. IJV has advantages in reducing the normalized concentration of pollutants and improving the IAQ. Increasing the number of air changes per hour (ACH) may lead to a longer MAA and reduced air exchange efficiency. Choosing an appropriate number of air changes is very important to improve the IAQ in the toilet.

The heat supply object thermal regime under conditions of gas infrared emitter and air exchange system joint operation

The paper presents the results of experimental studies on the formation of thermal comfort conditions in large premises with the joint operation of gas infrared emitters and air exchange ventilation system. The values of temperatures and heat fluxes on the clothing surface under natural and mixed convection conditions were obtained. It has been established that the air exchange system operation in the premises reduces the temperature drop of the person clothes surface, respectively, a more favorable temperature condition is achieved in the working area.

Study of the effectiveness of the use of closed-type UV-recirculators for air disinfection in enclosed space

Introduction. The research is devoted to assessing the results of our studies of indoor air concerning microbial contamination during the operation of a UV recirculator with different modes (different UV doses). Also, a theoretical calculation of the influence of the ratio of the capacity of the UV recirculator to the air volume of the treated room on the efficiency of air disinfection has been made. Materials and methods. The study of indoor air in terms of total bacterial count (TBC), including coccal microflora and yeast and mould fungi, were carried out. Air sampling and evaluation were carried out under the requirements of Methodical guidelines MUK 4.2.2942-11 “Methods of sanitary and bacteriological studies of environmental objects, air and sterility control in medical institutions”. The evaluation of the results was carried out following R 3.5.1904-04, "The use of ultraviolet bactericidal radiation for disinfection of indoor air". During the study, agar culture media were used: Sabouraud agar, yolk-salt agar (YSA), meat-peptone agar (MPA), nutrient agar with the addition of 5% sheep blood (blood agar), bismuth sulfite agar, XLD-agar, cetrimide-agar, “Shine” agar, Endo agar. Results. As a result of the studies carried out, it was shown that a dose of UV irradiation of the order of 12-15 mJ/cm2 leads to an insignificant change in the concentration of bacteria (TBC) and fungi in the air (the efficiency was 58% and 69%, respectively). UV doses of the order of 25-30 mJ/cm2 significantly reduce the concentration of bacteria (TBC) and fungi in the air (efficiency was 99.99% and 99.4%, respectively). A theoretical calculation showed that it is practical to use a UV recirculator of such a capacity that provides an air exchange rate in the room of at least 4 (with ventilation operating at a rate of at least 2). Conclusion. To effectively use UV recirculators in enclosed spaces against bacteria and fungi, it is necessary to use models that provide a UV dose of at least 25-30 mJ/cm2. In contrast, their air capacity should provide an air exchange rate of at least 4.

The question of determining installation sites for the Air purification of pig premises local system elements

The allocation of intake air stream in pig premises is not evenly. The existence of engineer-ing networks and equipment, the breaching of montage technologies of air ventilation, incorrect maintenance of air ventilation system – all these factors bring to many breaches and problems. This problem such as air exchange violation in all premises, appearing zones of stasis (aero stasis), and others. As a result of which the differential of temperature and humidity has appeared. These also appear excess maximum per-mitted concentration of dust and gases. The all-exchanged ven-tilation system can’t solve all problems in local zones in pig premises. In this local air-ventilation system become more demand. For effective work of local air ventilation, the question of deter-mining installation sites for the air purification of pig premises local system elements should be solved. Keywords: LOCAL VENTILATION, AIR CLEANING FROM DUST, DUST RELEASE, HARMFUL GAS CLEANING

Colliding respiratory jets as a mechanism of air exchange and pathogen transport during conversations

Air exchange between people has emerged in the COVID-19 pandemic as the important vector for transmission of the SARS-CoV-2 virus. We study the airflow and exchange between two unmasked individuals conversing face-to-face at short range, which can potentially transfer a high dose of a pathogen, because the dilution is small when compared to long-range airborne transmission. We conduct flow visualization experiments and direct numerical simulations of colliding respiratory jets mimicking the initial phase of a conversation. The evolution and dynamics of the jets are affected by the vertical offset between the mouths of the speakers. At low offsets the head-on collision of jets results in a `blocking effect', temporarily shielding the susceptible speaker from the pathogen carrying jet, although, the lateral spread of the jets is enhanced. Sufficiently large offsets prevent the interaction of the jets. At intermediate offsets (8-10 cm for 1 m separation), jet entrainment and the inhaled breath assist the transport of the pathogen-loaded saliva droplets towards the susceptible speaker's mouth. Air exchange is expected, in spite of the blocking effect arising from the interaction of the respiratory jets from the two speakers.

Substantiation of the hygienic standard for air exchange multiplicity in medical premises of ambulances built into residential houses for preservation and improvement of the health of medical staff

Objective: We substantiated a hygienic standard for air exchange multiplicity in the doctors’medical premises at the ambulances built into residential houses to preserve and strengthen their health. Materials and methods: The analytical method was applied in the work (regulatory framework of sanitary and town-planning legislation, development of the hygienic standard by calculation method). The air exchange calculation for the working places of family doctors of the built-in ambulances was carried out in accordance with the NBS B.2.5-67:2013 Heating, Ventilation and Air Conditioning. Results and discussion: The calculation of air exchange rate for the doctors’ working places of the healh care facilities built into the residential houses was carried out in accordance with the NBS B.2.5-67:2013 Heating, Ventilation and Air Conditioning (Annex X (mandatory) Minimum Outdoor Air Consumption) and corresponding formulas. To calculate the air exchange in the doctors’premises, the category of the works of the doctors of the ambulance medical practice, which refers to light physical (office) work by the category I; the number of nurses at work at the same time and the potential number of visitors (2 persons - doctor and patient; 3 persons - doctor, nurse and patient and / or doctor, patient and accompanying person; 4 persons - doctor, nurse, patient and accompanying patient person); the minimum air consumption per 1 person - 60 m3 / hour; the regulatory size of the area of the medical premises (12 m2, 18 m2) and different types of housing estate with 2.5 m and 3 m premise high were taken into account. Conclusions: To replace the current standard K = 1 (NBS B.2.2-10-2001 Health Care Facilities), the standards of optimal air exchange multiplicity K = 6.44 and K = 8.40 in doctors’ medical facilities with different sizes and the number of people staying simultaneously were substantiated on the basis of the conducted hygienic study of the conditions of the placement of modern health care facilities of ambulance type built into residential houses. In order to ensure strengthening and preservation of the health of medical staff and patients and to create the proper sanitary and anti-epidemic working conditions for staff, the health care facilities, built into residential houses, need the mechanical plenum-exhaust ventilation according to the new reasonable standards of air exchange multiplicity for medical premises.