Within creation of the mathematical model to describe the human respiratory system, we accomplished numeric investigation of non-stationary dust-containing airflow as well as dust particle deposition in the lower airways with the real anatomic geometry based on CT scans. Inhaled air is considered a multi-phase mixture of a homogenous gas and solid dust particles. Motion of a basic carrier gas phase is described using the Euler approach. Solid dust particles are a dispersed carried phase, which is described with the Lagrange approach. The k-ω model is used to describe turbulence. We consider non-stationary airflow during calm inhalation. The article presents calculated flow streamlines for the velocity of particles in inhaled air in the lower airways at different moments. We quantified a share of deposited particles (SDP) with various dispersed structure (between 10 nm and 100 µm) and density (1000 kg/m3, 2000 kg/m3, 2700 kg/m3) in the lower airways; the article provides computed motion paths of particulate matter. Solid particle deposition in the airways has different efficiency depending on particle sizes and density. SDP goes down as their sizes and masses decrease. Particle density mostly influences differences in deposition of micro-sized particles (2.5–20 µm): as particle mass and density grow, SDP in the airways also increases. SDP with their diameter being less than 1 µm amounts to approximately 20 % of all the particles that reach the inlet to the trachea. According to the results obtained by numeric modeling, the greatest share of dust particles penetrates the right main bronchus, predominantly the right middle and inferior lobar bronchi. Dust particles are able to induce diseases of the lungs, pneumoconiosis included.

The aim of this study was to estimate the risk of modified clinical course of viral respiratory diseases (influenza, ARVI, COVID-19) due to environmental exposures and effects of lifestyle factors considering regional peculiarities in the Russian Federation. The study relied on using data from federal statistical reports issued in 2010–2019 for 82 Russian regions. ARVI and influenza incidence was analyzed. A set of social and hygienic determinants (SHD) was represented by 112 indicators grouped in 7 domains. Multiple linear regression was used to estimate contributions made by unmanageable weather and climatic factors (UV-radiation intensity, humidity, air temperature, wind speed, deviation from average long-term temperature levels). An artificial neural network (multilayer perceptron) was used to assess effects produced by other environmental and lifestyle factors. Risk was calculated as a product of disease likelihood (Δp), determined by SHD, disease severity (g) and coefficient of modified disease duration (w). Approximately 60 % of actually registered annual ARVI and influenza incidence was found to be caused by combined effects of the analyzed factors. Weather and climatic factors had more stable and considerable effect on this incidence relative to other environmental exposures. A four-level scale for risk classification was created based on its calculated values over 2012–2019 (minimal, permissible, alerting, and high) together with outlining relevant risk management activities. Scenario calculations allowed revealing the most significant factors for decreasing ARVI and influenza incidence. If ranked in the descending order, they were quality of the public healthcare system, lifestyle, sociodemographic indicators, background incidence rates, economic indicators, and sanitary-epidemiological indicators (0.52, 0.49, 0.45, 0.32, 0.28 and 0.21 cases per 100 thousand people respectively). An increase in the number of vaccinated people was found to make the greatest contribution to incidence decline among all manageable factors (on average, 0.8 cases per 100 thousand people). The developed methodical approach based on a cascade of mathematical models, makes it possible to quantify contributions made by manageable and unmanageable factors to modified course of respiratory epidemics (ARVI and influenza). The study results and the risk scale can be used for substantiating targeted preventive and anti-epidemic activities, regional specificity taken in account.

This study focuses on developing a mathematical model of the respiratory system created by the authors. This model has been created to solve relevant tasks within assessing and predicting health risks caused by negative effects of airborne exposures. In particular, the main focus is on investigating dusted airflow and dust particle deposition in the human airways (from the nasal cavity to the fifth generation of the bronchi) under different breathing intensity. Inhaled air is considered a multi-phase mixture of a homogenous gas and solid dust particles. The three-dimensional geometry of the airways is based on CT scans. The study investigated non-stationary airflow during calm, deep and intense breathing. We quantified deposition of particles with different sizes (diameter between 0.5 µm and 20 µm) and density (1000 kg/m3, 2000 kg/m3, 2700 kg/m3 and 4000 kg/m3) in the airways during an inhalation of different intensity; provided velocity fields for inhaled air and motion paths for particles of various sizes. Large particles (more than 10 µm), which tend to be heavy, are almost completely (more than 90 %) deposited in the airways (predominantly in the nasal cavity, pharynx and larynx). As a particle size and mass (density) declines, the share of deposited particles goes down as well and, accordingly, there is a growth in the share of particles able to reach smaller airways and even the lungs. As breathing intensity grows, the share of deposited particles (diameter 2.5 µm and larger) increases as well. Particle density has a more pronounced effect on differences in deposition of micro-sized particles (sized between 2.5 and 10 µm); the higher is particle density, the higher is their mass (of particles with the same size) and the higher is the share of particles deposited in the airways. Deposition of smaller particles (sized 0.5 µm, 1 µm) differs only slightly depending on their density. Depending on breathing intensity, approximately 28–34 % of particles sized 1 µm or less is deposited in the analyzed section of the airways. These findings are qualitatively consistent with the results obtained by a conducted field experiment aimed at investigating regularities of distribution of ambient dust particles in the human airways.

Introduction. Micro- and nano-sized suspended particles may be toxic to humans more than larger particles. Effects of these particles can cause diseases of the respiratory, cardiovascular, endocrine and immune system, etc. There are no safety standards for micro-sized particles PM1.0 at present in the Russian Federation. The aim of this work is scientific substantiation of the safe level of micro-sized suspended particles PM1.0 in ambient air. Materials and methods. Safe PM1.0 levels in ambient air upon long-term inhalation intake were established on the base of selecting previously conducted relevant studies and assessment of the quantitative and qualitative data (assessment of study design elements, exposure levels, adverse health responses (effects), etc.) provided in them. In key studies ‘point of departure’ for exposure was established most relevant for substantiating safe PM1.0 levels; these levels were then calculated considering use of the total (complex) modifying factor. Results. Out of sixty eight publications reported the results obtained in studies with their focus on effects of PM1.0 on the health, two key studies were selected for the procedure for justifying the value of the PM1.0 safe level in ambient air, namely, Zhang et al., 2021 and Yu et al., 2020. The safe level for PM1.0 upon chronic inhalation exposure is scientifically substantiated at 0.002 mg/m3 based on establishing the values of modifying factors and calculating the total (complex) modifying factor. Limitations. The study does not provide any toxicological results. Conclusion. The proposed safe PM1.0 level in ambient air (0.002 mg/m3) has the potential for practical application in the health risk assessment as a reference concentration, as well as for use in the system for sanitary and hygienic regulation.

The article continues the series of studies that describe a mathematical model of the respiratory system developed by the authors and dwell on its use in practice to assess and predict risks for human health caused by negative effects of airborne environmental factors. The mathematical model includes several submodels that describe how an air mixture flows in the air-conducting zone (it includes the nasal cavity, pharynx, larynx, trachea and five generations of bronchi) and the lungs approximated with a continuous two-phase elastically deformed porous medium. The mathematical model is described by using continuum mechanics relationships. It is realized numerically by using engineering software (to investigate processes in the airways) and a self-developed set of programs (to simulate processes in the lungs). Numeric modeling of a non-stationary flow of an air-dust mixture is performed for a personalized three-dimensional geometry of the human respiratory system based on CT-scans. The study provides calculated lines of velocity for a flow of particles in inhaled air in the airways. We have quantified shares of deposited articles with their diameters being 10 µm, 2.5 µm, and 1 µm (РМ10, РМ2,5, РМ1) in the airways; the study also provides trajectories of particulate matter. As particles become smaller and lighter, the share of deposited ones goes down in the airways and grows in the lungs. According to numeric modeling, most (more than 95 %) large particles (PM10) are deposited in the nasal cavity, pharynx and larynx; small particles are able to reach the lower airways and bronchi (most particles that reach the lungs penetrate lobar bronchi predominantly in the right lung). Sites with maximum health risks in the human lungs have been identified relying on assessing changes in an air phase mass within the respiration cycle; they are located in lower lobes of the lungs. When contacting airway walls, particles are able to be deposited and accumulate over time producing irritating, toxic and fibrogenic effects; they can thus cause and / or exacerbate pathological states.

Introduction: Weather factors, including increasingly frequent heat waves, can raise human health risks. Objective: To propose methodological approaches allowing quantitative assessment of health risk levels related to exposure to meteorological factors using heat waves as an example. Materials and methods: The methodological approaches were developed based on conceptual provisions of the health risk assessment methodology and Russian Guidelines MR 2.1.10.0057–12, Assessment of risk and damage from climate changes that increase morbidity and mortality rates in at-risk populations. They were then tested on heat waves using air temperatures registered in the city of Perm from January 01, 1992 to December 31, 2022 and respiratory and circulatory disease incidence rates observed in 2010–2022. Results: Approaches to assessing human health risks posed by weather factors are described. They include priority setting criteria, description of exposures, formulas for calculating their levels and health risks given the severity of outcomes, and the rating scale. The results of testing the approach using data on 2010 heat wave in Perm showed that the total risk for the child population associated with respiratory diseases was 2.66 × 10–6; those for the adults and attributed to respiratory and cardiovascular diseases – 2.34 × 10–8 and 6.66 × 10–7, respectively; and those for the elderly population and related to respiratory and cardiovascular diseases were 1.81 × 10–6 and 1.03 × 10–5, respectively. The lifetime risks were ranked as minimal and acceptable. Conclusions: The suggested approaches facilitate quantitative assessment of risks posed by meteorological exposures taking into account severity of likely health outcomes and determination of their acceptability.

Introduction. Ambient air pollution is a widespread and pressing issue. This necessitates the development of methods for estimating and predicting progression of pathologies on the base of evolutionary mathematical models. Adaptation of the theoretical model to practice requires identification and verification procedures in real conditions of contamination of inhaled air with dust particles of various compositions. The purpose of the work was to investigate regularities of distribution of dust particles with a different disperse, component and morphological structure in the human airways after inhalation from ambient air. The study involved performing a field experiment. Materials and methods. We accomplished several investigations in 3 zones with different levels and structures of ambient air pollution. Disperse, component, and morphological structures of particles occurring in ambient (inhaled), deposited in various sections of the human airways, in exhaled air and blood were examined by electronic microscopy. Results. Air quality in zones 1 and 2 did not comply with hygienic standards for suspended particles, PM10, PM2.5, metal compounds, etc. (up to 3.29 MPCm.s., 3.2 MPCav.s., 2.91 MPCav.y.) and formed increased hazard quotient for manganese, copper, nickel and their compounds, inorganic fluorides, suspended particles (up to 5.48 HQac, 3.42 HQch), respiratory and other hazard indices (up to 5.48 HIac, 8.59 HIch). The degree of sedimentation of small particles (PM2.5 or less) in different parts of the respiratory tract is uneven, they are able to penetrate into the lower airways and lungs of humans. More than 65% of all the particles deposited in the upper airways had a diameter bigger than 10 µm. PM2.5 accounted for more than 60 % in sputum in the lower airways and the share of PM1.5 reached 46.7 %. Particles smaller than 1.5 μm (90.5%) were predominantly recorded in blood biosubstrates, of which up to 88.1% of the particles had a sphericity of 0.9–1.0. Limitations. Limited degree of precision of location of the examined sections in the respiratory system. Conclusion. Common deposition regularities are mostly determined by sizes and morphology of dust particles. The component structure of inhaled air has practically no effects on regularities of particle deposition in various sections of the respiratory system; however, it can have substantial influence on types of pathologies progressing in the body. High shares of PM1.5 identified in inhaled air, the lower airways and blood require considering levels of PM1.5 and smaller particles in ambient air in settlements to be covered by hygienic standards. In future, the study results will be used in numeric modelling of accumulation of functional respiratory disorders and associated pathologies of other organs and systems and in predicting development of pathologies based on evolution mathematical models.

The ongoing climate change makes its contribution to public health risks. These risks can be caused both due to direct impacts of the process and modifying influence exerted by climatic factors on chemical levels in ambient air. Given that, it is advisable to develop methodical approaches that give an opportunity to quantify public health risks under combined influence of climatic factors and chemical air pollution caused by them. In this study, we suggest methodical approaches eligible for calculating, assigning a category and assessing acceptability of public health risks under climatic exposures considering their influence on chemical air pollution. We outline approaches to establishing priority climatic factors, calculating exposure levels and associated responses; making up a list of chemicals levels of which are influenced by climatic factors and probable health outcomes caused by exposure to them; identifying levels of chemicals associated with climatic influence; calculating and assigning a category for public health risks associated with combined exposure to climatic and chemical factors using a multiple logistic regression model. We tested the approaches using data collected in Perm in 2020. As a result, we established an unacceptable health risk for working age population (1.11•10-4) due to cerebrovascular diseases (I60–I69). This risk was associated with combined exposure to climatic factors (heat waves) and associated chemical air pollution (high levels of carbon oxide). Risk levels for working age population and older age groups due to diseases of the circulatory system (ischaemic heart diseases (I20–I25) and other cardiac arrhythmias (I49)) were rated as permissible (acceptable), 7.68•10-5 and 4.07•10-5 accordingly. The contribution made by the analyzed climatic factor (heat waves) varied between 76.24 and 92.44 %; the analyzed chemical factor (carbon oxide), between 7.56 and 23.76 %.

The article is devoted to the main aspects of the development of a mathematical model of the human respiratory system taking into account the effects of environmental factors. The proposed model is a submodel of "meso-level" multilayered mathematical model of the evolution of functional disorders of the human body. The conceptual and mathematical formulations of the problem are discussed. The breathing is considered as a set of synchronized processes of gas dynamics, deformation of the porous medium and diffusion. The results of the calculation of the air flow characteristics during quiet breathing and forced breath in the first four generations of large airways were obtained by using software ANSYS Fluent. Further development of the model involves the joint problem solving of changes in lung configuration and in gasdynamic processes in the human airway.

As part of the mathematical model of the human respiratory system, a submodel is considered for the study of the non-steady airflow with solid particles (suspended particulate matter (PM) / dust particles) and the deposition of particles of various sizes in the human nasal cavity. It is assumed that the nasal cavity is divided by the bone-cartilaginous septum into two symmetrical (relative to the nasal septum) parts; the average geometry of the right part of the human nasal cavity is considered. The inhaled air is considered as a multiphase mixture of homogeneous single-component gas and solid dust particles. The Eulerian-Lagrangian approach to modeling the motion of a multiphase mixture is used: a viscous liquid model is used to describe the motion of the carrier gas phase; the carried phase (dust particles) is modeled as separate inclusions of various sizes. The process of heating the inhaled air due to its contact with the walls is also taken into account. The features of the unsteady flow of a multiphase air mixture with dust particles were obtained using Ansys CFX for several scenarios. It has been noted that when studying the airflow in the nasal cavity, it is necessary to take into account the presence of turbulence, for which it is proposed to use the k-ω model. The velocity fields of inhaled air in the nasal cavity have been obtained; presented temperature distributions in the nasal cavity at different time points; made estimates of air heating at different temperatures of inhaled air; gave estimates of the proportion of deposited particles in the nasal cavity depending on the particle size for real machine-building production; presented trajectories of movement of suspended particles. Thus, it is shown that more than 99.7 % of particles with a diameter of more than 10 microns deposit in the human nasal cavity; as the particle diameter and mass decrease, the proportion of deposited particles decreases. Suspended particles with a size of less than 2.5 microns almost do not deposit in the nasal cavity. They can penetrate deeper into the lower airways and lungs of a person with the inhaled air and, having fibrogenic and toxic effect, can cause diseases. The results obtained are in good agreement with the results of individual studies performed by other scientists. Further development of the model involves studying airflow in the human lungs and modeling the formation of diseases caused by the harmful effects of environmental factors (including dust particles) entering the human body by inhalation.

The article addresses development of methodical approaches to calculating levels of health disorders caused by short-term exposure to ambient air pollution. We have established and parameterized relationships relevant for quantification of probable health outcomes as responses to elevated levels of chemicals in ambient air higher than their reference ones. These relationships were modeled using system analysis techniques and were based on dynamic data series on ambient air quality at the control points and the number of applications for medical aid in settlements with their overall population being more than 5 million people. We have formalized relationships that describe how intensively acute health disorders develop under short-term exposure to chemical levels in ambient air being higher than the reference ones that are identified at the control points. The resulting models rely on official data and can be used to predict and assess public health risks in any area where ambient air quality is monitored. The formalized relationships were tested within identifying levels of incidence associated with acute short-term exposure to ambient air pollution in a large industrial center. It was established that, according to data collected in 2020, the highest associated incidence was caused by exposure to benzene (on average 0.364 mg/m3 higher than the reference level) in ambient air and was detected as per such nosologies as ‘Allergic rhinitis unspecified’ and ‘Predominantly allergic asthma’. We are planning to use the results obtained at this stage in the research in further development of methodical approaches to assessing and predicting chemical health risks in areas influenced by hazardous chemical objects under short-term exposure to high levels of pollutants.

Introduction: Solving problems related to reducing morbidity and mortality of the population and increasing life expectancy is one of the strategic goals of the development of the Russian Federation. Objective: To improve approaches to assessing losses to public health prevented through control and supervisory activities of the bodies and institutions of the Federal Service for Surveillance on Consumer Rights Protection and Human Wellbeing (Rospotrebnadzor). Materials and methods: For the first time, a new cascade model has been proposed for assessing and predicting prevented health losses in the triple system “control and supervisory activities of Rospotrebnadzor – environmental quality indicators – population health.” Thirty-five new neural network models were obtained to describe the relationships between factors characterizing the activities of Rospotrebnadzor and indicators of the quality of environmental media. New approaches have been developed to estimate the decrease in the modified indicator of life expectancy, which describes healthy life expectancy, based on prevented disease and death cases. Results: The proposed approaches were tested using the example of the Russian Federation as a whole. The estimates showed that the proportion of prevented cases relative to actual levels for the entire population ranged from 0.8 % to 32.6 % depending on the disease category while the proportion of averted deaths ranged from 1.8 % to 13.4 %. In total, about 4.8 % of cases of total morbidity and 2.6 % of cases of all-cause mortality were prevented as a result of control and surveillance activities, while the prevented loss of modified life expectancy was about 1.14 years. Conclusions: The results of this work can be used in the future to assess economic losses associated with health damage and to evaluate the efficiency of control and supervisory activities. To establish priority types of the latter, additional numerical experiments are required, which may be the subject of further research.

The relevance of the present study follows from the necessity to establish parameterized cause-effect relationships that describe additional disease cases among population caused by chronic exposure to chemical factors. In this study, our aim was to explore relationships within the ‘environment – public health’ system to quantify and predict chronic risks under exposure to chemicals in ambient air. To achieve this, we collected statistical data on some municipalities located in the Russian Federation with different structures and levels of chemical pollution in ambient air. Data on population incidence and ambient air quality were coordinated at places where calculation points were located; these points were centers of residential buildings and their coordinates were applied in the study. Mathematical modeling of the relationships was conducted by using multiple linear regressions. Pollution indicators (chemical concentrations in ambient air) that met the requirements of biological plausibility and statistical significance of pair correlations were selected as independent variables. The obtained regression models contain 190 factors for 36 chemicals occurring in emission into ambient air from stationary and mobile sources, which allow calculating the frequency of additional disease cases for 29 diseases. The established factors make it possible to perform operative estimations of a number of diseases associated with ambient air quality at a place of residence relying on medical aid applications. The resulting relationships can be used to predict chronic health risks. Establishing criteria for ranking chemical health risks in zones influenced by hazardous chemical objects can become a next step in development of the suggested approaches.

The existing model of control and surveillance activities is based on a procedure that involves assigning activities performed by juridical persons or private entrepreneurs and (or) production facilities used by them in these activities into a specific risk category or a specific hazard class (category). The goal of the present work was to develop and improve algorithms for drawing up annual plans of inspections performed by Rospotrebnadzor’s territorial organizations within the framework of the risk-based model. For the first time, we have formulated conceptual and mathematical statement of the problem of planning control and surveillance activities performed by Rospotrebnadzor. This allowed us, among other things, to consider history of violations (integrity of a given subject) over a specific period and availability of objects for inspections. The latter is described with several parameters that include both regional peculiarities (a distance between objects, quality of road networks) and “complexity” of checking a particular object. When analyzing the mathematical statement, we identified certain model parameters that had the greatest influence on a solution to the problem, that is, the most sensitive parameters that should be regulated with special care if we want to make control and surveillance activities more effective. We have created planning algorithms with preset parameter values (scenario forecasting programs) and tested them at the regional level. We have developed three criteria for comparing these algorithms: coverage of a number of subjects that are to be inspected; coverage of a number of objects that are to be inspected; coverage by the total risk. The testing results indicate that the combined algorithm has higher coverage rates since in this case not all objects are inspected when a given subject is being checked. Consequently, this allows reducing overall labor costs required to perform an inspection. The suggested approaches give an opportunity to achieve more effective distribution and use of resources allocated by Rospotrebnadzor for scheduled inspections.

In the Russian Federation, the problem of atmospheric air pollution is relevant for most regions. Based on the dispersion calculations, the risk to the Bratsk population's health from the chemicals that pollute the air was assessed. It was found that short-term effects of atmospheric pollution cause non-carcinogenic risks to the respiratory system, the immune and blood systems, systemic disorders and damage developmental processes. More than 95% of the contribution to the aggregate level of acute risks are made by dust, nitrogen dioxide, sulfur dioxide, gaseous fluorides, and benzene. Chronic exposure increases the level of the carcinogenic risk, causes the non-carcinogenic risk to the respiratory system, the skeletal system, blood damage and developmental disorders. More than 95% of the contribution are made by nitrogen oxides, sulfur dioxide, gaseous and poorly soluble fluorides, benzene, benzo (a) pyrene, carbon, hexavalent chromium and dust. A list of 13 priority pollutants that should be regularly monitored in Bratsk was compiled.

In The Russian Federation, increasing of life expectancy and decreasing of mortality related to diseases of circulatory system are the priorities of state policy. The purpose of study was to develop approaches to the classification of cardiovascular diseases by severity degree within the framework of development of general health management model based on health care activities at the regional level. The article describes methodology of calculating indices of cardiovascular diseases severity based on statistical data of appealability for out-patient, in-patient and emergency medical care. The set of balancing coefficients reflecting input of rate of accessing for various types of medical care, as well as aggravating input of concomitant pathology, based on expert evaluation of cardiologists involved is presented. On the basis of analysis of distribution of severity index in standard region of the Russian Federation, the system of criteria was developed to classify cardiovascular diseases (according to ICD-10 sub-classes) on four degrees of severity. The approbation of the proposed method demonstrated adequacy of the results obtained to judging of experts (cardiologists). So, in standard region of the Russian Federation, in the class of diseases of circulatory system (I00-I99), 79.6% of all cases are of first degree of severity, 8.6% of cases are of second degree of severity, 3.8% of cases are of third degree, and 8% of cases are of fourth degree. The methodology is unified and can be applied to classify entire spectrum of diseases by degree of severity. Besides, the proposed methodological approaches are suitable to be applied in population health management at the municipal, regional and national levels in the Russian Federation.