Air Ion Concentration Research Articles

Ensuring the normalization of the aero-ionic regime in production areas by means of ultrasonic air ionization

The results of studies on the normalization of the aeroionic regime in rooms under ultrasonic ionization of humidified air are presented. The increase in the concentration of negative aeroions under these conditions by the combined effect of the balloelectric effect and ultrasonic cavitation is substantiated. It has been established that when distilled water is used as a source of air ions under the action of a 10 W ultrasonic generator at a distance of 0.5 m, the concentration of negative air ions increases almost sixfold. At the same time, due to the joint effect of ultrasonic cavitation in the surface layer of water and the balloelectric effect, no generation of ozone and nitrogen oxides is caused. It is proved that with a decrease in the degree of water mineralization, the concentrations of negative and positive aeroions increase due to changes in the physicochemical properties of water and the resulting mechanochemical phenomena. The mechanism of formation of air ions in the air of industrial premises under the combined action of the balloelectric effect and ultrasound is proposed. It is substantiated that the quality of the air ionic composition of industrial premises air improves at a temperature of demineralized water of 20-25 °C and a directed air flow of 6 m/s towards the working area with the combined effect of ultrasound and balloelectric effect, which contributes to the improvement of sanitary and hygienic working conditions. The structure of an automated system for controlling the aeroionic regime of the working area of industrial premises with artificial ionization of humidified air using an aeroion generator and a ventilation system is proposed. This will allow monitoring and processing of information on technological, electrical and microclimatic parameters, adjusting, coordinating and jointly controlling the ventilation system devices and the ultrasonic generator of air ions.

Impact of Pulse Electric Field Stimulation on Negative Air Ion Release Capacity of Snake Plants

To investigate the effects of pulse electric field stimulation on the photosynthetic electron transport chain and negative air ion (NAI) release capacity of snake plants, the chlorophyll content, fluorescence induction kinetics curve (OJIP curve), chlorophyll fluorescence parameters, and NAI release concentration of snake plants kept under identical greenhouse conditions under different pulse electric field stimulations were compared and analyzed. The experimental results show that (1) after pulse electric field stimulation, the chlorophyll content in treatment group T1 (5 kv) and T2 (7 kv) of snake plants increased by 6.30% and 6.70%, respectively, with significant differences observed between the two treatment groups and the control group (CK). (2) In both treatment groups, the OJIP curve exhibited higher values for the inflection point (I) and peak (P) compared to the origin (O) and inflection point (J) values, with the rising trend in the I–P segment being more gentle than that of the O–J segment. Additionally, the J band was above 0, with the peak value in the T2 group being higher than that in the T1 group. (3) The chlorophyll fluorescence parameters showed fluctuating variations. Specifically, Fm, TRo/CSo, ETo/CSo, and DIo/CSo showed ascending trends in the treatment groups. Fv/Fo, Sm, and ABS/RC exhibited descending trends; Fv/Fm, Vj, ETo/RC, and φEo showed relatively minor changes. The PIabs displayed a decreasing trend. The PItotal in the CK was greater than that in the T1 and T2 groups. (4) After 4 h of pulse electric field stimulation, the NAI concentration increased by 87.60% in the T1 group and by 62.09% in the T2 group, compared to the same measurement taken at 3 h. Pulse electric field impacts the photosynthetic electron transport chain of snake plants, thereby influencing their NAI release capacity. This study aims to elucidate the physiological responses of the chloroplasts in snake plants to pulsed electric field stimulation and to lay the foundation for enhancing the plant’s release of negative air ion concentrations through physical and technological means.

The Combined Effects of the Thermal Environment and Air Quality at Recreation Places on the Physiology and Psychology of People in Urban Parks

Urban forests, crucial to urban ecosystems, are increasingly threatened by the challenges of urbanization, such as deteriorating thermal environments and declining air quality. Despite their recognized benefits to city dwellers’ quality of life, a systematic understanding of the impact of these environmental factors on public psychophysiological well-being in recreational sites is a notable gap in the literature. The objective of this research was to bridge this gap by examining the effects of the thermal environment and air quality in urban forests on the public’s perception, offering scientific evidence to inform environmental optimization and health management strategies for urban parks, essential for sustainable urban development and public health. Three urban parks in Fuzhou, Fujian Province, namely Fuzhou National Forest Park, Xihu Park, and Jinniushan Sports Park, were selected as research sites. Environmental monitoring and questionnaire surveys were conducted at 24 recreation places from October to December 2020, collecting temperature, humidity, and wind speed; the atmospheric composition includes PM2.5, PM10, negative oxygen ion, and psychophysiological data from the public. Multivariate statistical methods were employed to assess the environmental characteristics of different recreation places types and their impact on public health. The findings reveal that environmental factors explained 1.9% to 11.8% of the variation in physiological and psychological responses, mainly influenced by temperature, wind speed, and negative oxygen ions. Forests and waterfront recreation places significantly outperform canopy and open recreation places in promoting mental invigoration, stress relief, emotional tranquility, and attention restoration. Environmental monitoring results indicate that favorable meteorological conditions and good air quality are crucial for enhancing the service functions of recreation places. Notably, the positive correlation between a negative air ion concentration and psychological well-being provides a novel perspective on understanding the health benefits of urban forests. The thermal environment and air quality of urban recreation places exert a significant influence on the psychophysiological status of the public. Increasing green coverage, improving water body environments, and rationally planning recreation places layout are of great theoretical and practical significance for enhancing the environmental quality and service functions of urban forests.

Activity concentration of indoor radon and its short-lived progeny (218Po, 214Pb, and 214Po) and their effect on atmospheric ionization rate in Sana'a, Yemen

Exposure to ionizing radiation inside houses, especially radionuclides of radon and its progeny, poses serious health risks that can be exacerbated when inhaled as a result of interaction with human lung tissue. Also, air ionization is mainly due to these radionuclides. Therefore, accurate measurements of radon activity concentrations and its short-lived progeny are required to assess dose and environmental pollution and estimate ionization rates in indoor environments. For this purpose, we employed a previously tested and approved reliable method, following the three-count procedure. This method is based on airborne radon progeny sampling on polycarbonate membrane filters and alpha counting using a passive α-dosimetry technique with CR-39 detectors. The method also relies on a PC-based software we developed for solving mathematical equations and calculating all the necessary physical quantities. In this study, the concentrations of radon and individual short-lived radon progeny were measured in 20 houses in Sana'a, Yemen. Measurement conditions and meteorological variables were considered. The average activity concentrations of 222Rn, Equilibrium-Equivalent Concentration (EEC), 218Po, 214 Pb, and 214Po were 73.1 ± 6.0, 29.2 ± 2.4, 44.4 ± 3.6, 30.5 ± 2.5, and 23.2 ± 1.9 Bq.m-3, respectively. The calculated average unattached fractions f1(218Po), f2(214 Pb), and fp were found to be 0.24, 0.04, and 0.07 % respectively. The annual average values of ion-pair production rate caused by 222Rn and their progeny and air ion concentration, were 27.25 ions.cm-3s-1 and 1829 ions.cm-3 respectively. The annual effective dose was estimated to be 1.93 ± 0.16 mSv.y−1, well lower than the recommended 10 mSv.y−1.

Application of DBD air plasma for indoor particulate matter removal

The use of non thermal plasma (NTP) to improve indoor air quality (IAQ) has grown considerably in recent years. This paper demonstrates the advantage of NTP for IAQ improvement in terms of particulate matter (PM) removal. The PM removal mechanism using active air ions and radicals has been investigated. From the developed dielectric barreir discharge (DBD) air plasma reactor, the total PM removal efficiency of 61.72% has been achieved at an optimised concentration of negative and positive air ions in 2 hours of continuous operation. Due to the utilised sensor's limit of quantification (LOQ), PM 2.5 and PM 10 have been reduced to a certain value. The findings revealed that DBD air plasma can be effectively used for PM removal in an enclosed environment.

Study of air deionization factors

The object of research is the dynamics in the concentration of air ions and suspended particles in atmospheric air and in supply-exhaust ventilation systems. An urgent task is to determine the factors and obtain quantitative data on the deionization of the atmospheric air that enters the environment where people live. Quantitative data on changes in the concentration of air ions depending on the time of day, temperature, and relative air humidity have been established. It was shown that even in the absence of significant man-made influence on the concentration of suspended particles, this indicator is at least 7000 cm-3. In the presence of wind, this indicator reaches 30000 cm-3 and higher. Measurement of the spectrum of suspended particles in the range of 0,3–6,0 μm showed that the predominant fraction is particles with sizes of about 3 μm. Studies have been conducted on changes in the concentrations of air ions in supply-exhaust ventilation systems. It was established that in the air duct made of galvanized iron, which has a length of 16 m, the concentration of negative air ions is reduced by 67 %, and positive by 78 %. Laboratory studies of air deionization in air ducts made of different materials were carried out. There is significant air deionization in metal and cardboard ducts while it is absent in wooden ducts. This indicates the electrical nature of deionization. A calculation method for forecasting the aero-ionic mode of premises, taking into account the factors of air deionization, is proposed. For rooms with supply-exhaust ventilation, a calculation apparatus is proposed taking into account the air exchange rate (the number of complete air changes per unit of time). The results make it possible to choose the required performance of artificial air ionization devices for normalizing the aero-ionic regimes in the premises

Factors Influencing the Concentration of Negative Air Ions in Urban Forests of the Zhuyu Bay Scenic Area in Yangzhou, China

Factors Influencing the Concentration of Negative Air Ions in Urban Forests of the Zhuyu Bay Scenic Area in Yangzhou, China

Temporal Dynamics and Influencing Mechanism of Air Oxygen Content in Different Vegetation Types

Air oxygen content, an essential index for measuring air quality, is affected by vegetation and the environment in the forest. However, the scientific understanding of the influential mechanism of air oxygen content in different vegetation types is still not clear. Focusing on four different vegetation types: broad-leaved forest, coniferous forest, coniferous and broad-leaved mixed forest, and non-forest land within Shimen National Forest Park, China, the temporal dynamics of air oxygen content and its relationship with four environmental factors (temperature, relative humidity, wind speed, and negative air ion concentration) in different vegetation types were explored based on path analysis and decision analysis. The results showed that there was a noteworthy impact of vegetation types on air oxygen content, with coniferous and broad-leaved mixed forest (21.33 ± 0.42%) presenting the highest levels. The air oxygen content indicated a fundamentally consistent temporal pattern across different vegetation types, with the highest diurnal variation occurring at noon. It reached its peak in August and hit its nadir in December, with summer > spring > autumn > winter. In broad-leaved forest, the air oxygen content was determined by temperature, wind speed, negative air ion concentration, and relative humidity; in both coniferous forest and coniferous and broad-leaved mixed forest, the air oxygen content was affected by temperature, wind speed, and relative humidity; in non-forest land, the air oxygen content was influenced by temperature and wind speed. Generally, temperature was the dominant factor affecting air oxygen content in different vegetation types, and its positive impact tremendously exceeded other environmental factors. Wind speed had a positive impact on air oxygen content in three forest communities but a negative effect on non-forest land. Relative humidity acted as a limiting factor for air oxygen content within three forest communities. Negative air ion concentration showed a significant positive correlation on air oxygen content in broad-leaved forest. Therefore, when planning urban forests to improve air quality and construct forest oxygen bars, it is recommended that the tree species composition should be given priority to the coniferous and broad-leaved mixed pattern. Meanwhile, make sure the understory space is properly laid out so that the forest microclimates are conducive to the release of oxygen by plants through photosynthesis.

Stand structure and environment jointly determine negative air ion concentrations in forests: Evidence from concurrent on-site monitoring in four typical subtropical forests during the growing season

Negative air ions (NAIs) have been extensively studied by scientists and administrators due to their crucial role in assessing the benefits of forest health to humans and improving air quality. This paper presents the results of a study conducted in four typical subtropical forests, where 24-hour on-site monitoring of NAIs, air temperature, relative humidity, wind speed, direct radiation, and particulate matter was conducted during the growing season. The vegetation characteristics of these forests were also investigated. Correlation and random forest analyses were employed to jointly evidence the effects of stand structure and environmental factors on NAI concentrations using mean data for the monitoring period. Additionally, regression analyses were employed to discuss the response of NAIs to continuous changes in meteorological factors using screened nighttime data. Our analysis revealed that NAI diurnal dynamics followed a unimodal pattern, with peaks observed in the afternoon (13:30–16:30) and troughs in the early morning (4:00–7:00). Significant variations in NAI concentrations were observed among the forest types, with mixed broadleaved forest showing the highest concentrations, followed by phoebe forest, Moso bamboo plantation, and Chinese fir plantation. The differences in NAI concentrations among forest types were primarily influenced by plant density at monitor heights, plant diversity, leaf area index, and tree height diversity. Overall, NAI concentrations were positively influenced by temperature and relative humidity and negatively influenced by particulate matter, while the influence of wind speed varied with forest type. Furthermore, our findings indicate that changes in particulate matter had a greater contribution to NAI concentrations compared to meteorological factors. By quantifying the spatial and temporal characteristics of NAIs in typical subtropical forests and their relationships with influencing factors from the perspectives of both stand structure and environment, our study provides new insights into scheduling human forest therapy activities and managing therapeutic forests.

Relative Humidity Dominances in Negative Air Ion Concentration: Insights from One–Year Measurements of Urban Forests and Natural Forests

Forests are one of the most important sources of negative oxygen ions (NAIs). NAIs have been recognized as beneficial for both physical and mental well–being, and higher concentrations of NAIs have been associated with improved health. However, the environmental factors that predominantly influence NAI concentration and their relationship with NAIs remain uncertain. This study aims to investigate the dominant factors and their impact on NAI concentration by observing NAIs and various environmental factors in two different environments (natural forest and urban forest) in the Beijing region over a one–year period. Through our investigation, we aimed to identify the key factor as well as other influential variables affecting NAI concentration. Our analysis encompassed the examination of dynamic concentration changes over multiple time scales, revealing uniform trends in both forest types. Notably, natural forests consistently demonstrated higher NAI concentration across these time scales, attributable to greater vegetation density and the stability of the forest microenvironment. By utilizing regression, correlation analysis, and structural equation analysis, we determined that relative humidity (RH) has the most significant effect on NAI concentration. Notably, both NAI concentration and RH displayed similar patterns across multiple time scales. When considering hourly average daily variation, the lowest values for both NAI concentration and RH were observed at noon, followed by an increase that persisted throughout the night. Seasonal average variation showed that both NAI concentration and RH peaked in the summer, followed by autumn. In terms of daily average annual variation, summer exhibited more days with high NAI concentration and high RH, which can be attributed to the increased rainfall during that season. Rainy weather was found to contribute to higher NAI concentration and RH levels. Furthermore, our findings revealed that on a daily scale, high RH and high NAI concentration occurred more frequently under conditions of high air temperature and low wind speed. However, the air quality index demonstrated only a minor effect in urban forest, while net radiation exhibited no significant influence on NAI concentration and RH. The fitted equations and trends of the aforementioned environmental factors with NAI concentration and RH were found to be comparable. The path analysis further corroborates these conclusions. The findings of this study indicate that RH is the primary factor driving the fluctuations in NAI concentration across various time scales, including hourly, daily, and seasonal variations. The study revealed that wind speed indirectly impacts NAI concentration by modulating RH. In contrast, air temperature influences NAI concentration both indirectly through RH and directly. The environmental factors affecting NAI concentration in the two types of forests are similar, but the degrees vary; in urban forests, wind speed, air quality index, and RH are slightly higher, while in natural forests, air temperature is slightly higher. This discovery further enhances our understanding of the underlying mechanisms and dynamic changes in NAI concentration within urban forests and natural forests. Moreover, it confirms the reliability and effectiveness of using RH as an indicator to monitor changes in NAI concentration over time.

Study of the Delayed Pumping Effect in an Underground Laboratory by Correlation Analysis of Radon and Air Ion Concentrations

Study of the Delayed Pumping Effect in an Underground Laboratory by Correlation Analysis of Radon and Air Ion Concentrations

DEVELOPMENT AND RESEARCH OF THE FUNCTIONAL POSSIBILITIES OF THE AUTOMATED FUZZY INDOOR AIR QUALITY MANAGEMENT SYSTEM OF PRODUCTION PREMISES

Purpose. Development of a fuzzy indoor air quality control system and research of the efficiency of an automated complex for increasing the concentration of air ions, namely a small-sized ultrasonic generator of air ions and a pump unit in the conditions of a complex ventilated air environment of work premises. Design/methodology/approach. The comprehensive research carried out is important in the context of the development of measures and means and the research of their effectiveness in maintaining the aeroionic regime of industrial premises at the regulatory level. Conclusions. The structure of an intelligent indoor air quality control system is proposed, which implements a combined change in the rotation speed of the fan and pump and the power of the ultrasonic aeroion generator. For the first time, a formalized criterion for the optimality of the indoor air quality management system is proposed, which depends on individual preferences of people regarding the comfort of the production environment and standardized parameters of temperature, relative humidity, and concentration of air ions in the working space. The task of the intelligent control system is to minimize the proposed criterion. Limitations/consequences of research. The proposed recommendations are universal and can be used in various areas of business to create safe and harmless working conditions in production. Practical consequences. The use of the developed small-sized ultrasonic aeroion generator not only significantly increases the concentration of aeroions in the working area, but also due to the baloelectric effect minimizes the negative impact inherent in most existing ionizers, namely the generation of ozone and nitrogen oxide, which significantly improves indoor air quality and thereby increases the level of industrial safety and labor protection. Originality/meaning. The existing control systems assume that standard ionizers (corona discharges) are inserted in the room, so there was a need to develop and research a modern intelligent system for controlling the quality of the indoor air in the working area of industrial premises using an aeroion generator and automated displacement ventilation.

Study on the Comprehensive Health Effects of Coastal Green Areas in Qingdao City, China

The recuperation factors (negative air ion concentration, airborne particulate matter, human comfort index, and acoustic environment index) of coastal green spaces have significant health effects. Most current studies focus on the distribution pattern of single recuperation factors in the forest environment; however, the comprehensive health effects of coastal green spaces are still unknown. To address this, we analyzed the distribution patterns of single and comprehensive health factors in different landscape configurations, landscape compositions, and coastal distances by principal component analysis and systematic clustering. The results show that: (1) coniferous and broadleaf mixed forests exhibit higher integrated health benefits than other landscape compositions; (2) closed and partially closed landscape configurations exhibit enhanced potential for promoting health benefits as opposed to partially open and open spaces; (3) a coastal distance of 150–300 m offers the strongest comprehensive health benefits. These findings collectively suggest that the increased cultivation of closed and partially closed mixed coniferous and broadleaf forest species at a distance of 150–300 m could effectively provide higher comprehensive health effects. Our study complements the ecosystem service of coastal green areas, especially in coastal health ecological services, providing support for coastal rehabilitation landscape planning; and can help to guide tourists in scheduling coastal health activities scientifically.

The Ecological Healthcare Benefits and Influences of Plant Communities in Urban Wetland Parks

Plant communities in urban wetland parks (UWP) have significant eco-healthcare benefits in terms of regulating the climate and improving the human living environment. However, factors influencing the regulation of eco-healthcare benefits are unclear. Taking Huaxi Ten Mile Beach National Urban Wetland Park as an example, the urban wetland park comprehensive healthcare index (UPCHI) was constructed based on an outdoor survey and indoor analysis to evaluate the UWP’s eco-healthcare benefits. Pathway analysis was used to investigate how climatic, geographic, and plant factors interact to affect the UPCHI. The results show that, over the whole year, tree–shrub–herb showed the best performance in terms of reducing PM2.5, PM10, and noise, as well as raising negative air ion concentrations; however, human comfort performed the worst. The UPCHI was generally beyond level Ⅲ (0.49–0.58) in the spring and summer, indicating that there are eco-healthcare benefits. Overall, the deciduous tree–shrub–herb community had the highest annual mean UPCHI, and more than half of the plant communities’ eco-healthcare benefits were class Ⅱ, which is very beneficial for eco-healthcare. The main direct factors on UPCHI were illumination intensity (0.68) and tree height (0.90), while canopy height (0.64–0.59) and tree crown radius/canopy height (0.72–0.14) directly or indirectly influenced UPCHI. The distance from the edge of the mountain (−0.39–−0.322) had a direct negative, but minor, effect on UPCHI. This study will assist residents with selecting suitable times and places for wetland recreation and healthcare activities, and it offers a valuable reference for the future planning and design of UWP plant communities.

Temporal Variation Characteristics of Negative Air ion Concentration and Air Quality Evaluation in Songshan National Nature Reserve, Beijing

Temporal Variation Characteristics of Negative Air ion Concentration and Air Quality Evaluation in Songshan National Nature Reserve, Beijing

A system for monitoring the microclimate parameters of premises based on the Internet of Things and edge devices

Recent years have been characterized by the rapid development of Internet of Things (IoT) and edge device technologies. Systems of various purposes with IoT elements and edge devices are increasingly finding practical use in people’s lives, the IoT element base is expanding and improving, which makes it possible to develop effective measuring systems, including those with feedback control. An essential role in ensuring people’s lives is played by the microclimate of the premises where people live, work, and study. As you know, the excess or decrease of the environmental microclimate relative to the norm negatively affects the physiological state of a person, his performance, and concentration and reduces the efficiency of work and training. Therefore, in this work, the problem of round-the-clock monitoring of the microclimate of classrooms is solved by developing an autonomous IoT system using edge devices to measure climatic parameters such as temperature, relative humidity, carbon dioxide level in the air, and the concentration of light air ions with data recording on a smartphone and saving on a remote server. The principles of building microclimate monitoring systems are presented, the requirements for the system are set, the criteria for choosing the elemental base and the technical characteristics of each component are given. The structure of the air ion concentration sensor developed by the author and the method of measuring the air ion concentration in the room are also described. The structural diagram of the developed microclimate parameters monitoring system is also presented. The development is part of a system for studying the influence of microclimate parameters on the physiological state of applicants for education. The results obtained in the work will allow development measures to ensure the necessary normal conditions for training in confined spaces. Research conducted using the developed system will allow better formation of student learning conditions in order to achieve maximum performance indicators.

Simultaneous observations of atmospheric vertical potential gradient from coastal Antarctic stations Bharati and Maitri

Simultaneous observations of the atmospheric electric potential gradient (PG) at Bharati and Maitri stations were studied from 2014 to 2016. A new regional diurnal pattern of fair-weather PG for the coastal Antarctic region, perhaps the ubiquitous characteristics of the PG for the coastal Antarctic region, has been identified. This pattern has a significant broad minimum around noon hours. It is around this time the wind speed is also maximum. The PG data of past years of Syowa, Vostok, and Carnegie Cruise were also used in this study. The surface wind distorts the fair-weather diurnal pattern of PG over Bharati more intensely than at Maitri. The katabatic wind effect on the PG at Bharati appears to be more intense than at Maitri. The topography and katabatic winds associated with the Lambert glacier could be the reason. The observation of Bipolar Air Ion Concentration (BAIC) suggests that the wind speed significantly affects the concentration by accumulation and dispersion. The concentration is maximum when the wind speed is minimum. As the air ion concentration controls the conductivity, the PG is expected to be minimum during these hours to produce an anomalous diurnal pattern in the PG at Bharati. Data quality is improved by measuring the PG with a field monitor at the surface level instead of at an elevated position. This study provides new hope in pursuing globally representative data of the PG for further investigations on the global thunderstorm activity and the solar-terrestrial weather relationship.

The effect of air velocity and indoor ambient properties on the effective operating range of an air ionizer device

Air ionizers are devices that purify the indoor air by artificially generating negative air ions (NAIs) which are proven to improve air quality and well-being of humans. Hence, more ionizers are being incorporated into heating, ventilation and air conditioning (HVAC) applications nowadays. . Every ionizer has its effective range of operation, which is the area inside a room that can potentially be covered by significant concentration of NAIs compared to the general concentration of ions naturally present in the room. This range may change depending on the indoor temperature, humidity and fan speed of the HVAC unit as preferred by the room occupants. Present research intends to design an experimental setup that could measure negative air ion (NAI) concentration at varying distances from an ionizer under different values of the aforementioned parameters. The experiment was conducted inside an indoor psychrometric test room to allow controlling of ambient temperature and humidity. Air velocity through the ionizer was varied from 1.5 m/s to 4.5 m/s, whereas the range of temperature and relative humidity were set from 25°C to 31°C and 60% to 80% respectively. To evaluate the ionizer’s operating range, NAI concentration was measured at every preset longitudinal (0 cm to 75 cm), lateral (-25 cm to 25 cm) and elevation (-15 cm to 15 cm) distance relative to the ionizer for 6 minutes using an ion counter named “Air Ion Counter Model AIC2”. The results reveal that the ionizer’s effective operating range increased with velocity, with the furthest range recorded at 4.5 m/s. Whereas a negative correlation was found between the ionizer’s effective operating range with temperature and humidity, with the furthest range recorded at 25°C and 60% respectively. The results also show that most ions were distributed in areas below and towards the right side from the ionizer’s perspective.

Exurban and suburban forests have superior healthcare benefits beyond downtown forests

Forests in urban areas provide great healthcare benefits to citizens, but it is less well known whether this benefit is related to different geographical spaces. We selected exurban forest, suburban forest, downtown forest, and urban control in Guangzhou, China to analyze the change characteristics of negative air ion concentration (NAIC), air oxygen content (AOC), and human comfort index (HCI). Based on Criteria Importance Through Intercriteria Correlation (CRITIC) method, the urban forest comprehensive healthcare index (UFCHI) was established. Finally, the evaluation criteria for UFCHI were identified by cluster analysis. The results demonstrated that (1) The NAIC in exurban forest (2,713 ± 1,573 ions/cm3) and suburban forest (2,147 ± 923 ions/cm3) was evidently better than downtown forest (1,130 ± 255 ions/cm3) and urban control (531 ± 162 ions/cm3). (2) The AOC was in the order of exurban forest (21.17 ± 0.38%) > suburban forest (21.13 ± 0.30%) > downtown forest (21.10 ± 0.16%) > urban control (20.98 ± 0.12%). (3) The HCI in urban control (5.56 ± 2.32) and downtown forest (5.15 ± 1.80) is higher than suburban forest (4.02 ± 1.53) and exurban forest (3.71 ± 1.48). (4) The UFCHI in exurban forest (1.000), suburban forest (0.790), and downtown forest (0.378) were beneficial to human health to some extent, while urban control (0.000) was at Level IV, having no healthcare benefit. Except in winter, the UFCHI in exurban forest and suburban forest were all at Level II and above; while downtown forest and urban control were all at Level III and below at all seasons. Overall, urban forests in the exurbs and suburbs have better healthcare benefits than those in the downtowns. Furthermore, it is recommended that urban residents visit exurban and suburban forests for forest therapy in spring, summer, and autumn.

Characteristics of the Immune and Neuroendocrine Status of Children Exposed to Non-Ionizing Radiation in the School Environment

Introduction: The modern educational environment involves the use of various electronic devices generating physical hazards. In addition to the widespread use of these devices, other physical factors of the school environment also affect schoolchildren’s health. However, the impact of the combined exposure to physical factors of various nature on the regulatory systems of the body has been studied insufficiently so far. However, the influence of a complex of physical factors of various nature on the regulatory systems of the body has not been sufficiently studied. Objective: To evaluate the features of the immune and neuroendocrine status of schoolchildren exposed to heterogeneous physical factors of a non-ionizing nature at school and to analyze the relationship between the studied physical factors and changes in the parameters of regulatory systems. Materials and methods: The exposed group included 144 students of a gymnasium from the city of Perm and the unexposed (reference) group consisted of 114 schoolchildren from the town of Kungur, Perm Region. We measured physical factors of the school environment, including noise, artificial illumination, electromagnetic radiation, and air ion concentrations affecting elementary, secondary, and high school students from both groups and compared the results with respective permissible levels. The indicators of immune (CD-phenotyping, phagocytic activity of leukocytes, concentrations of immunoglobulins and cytokines) and neuroendocrine (TSH, free T4, and cortisol) systems were established and compared. Mathematical models were calculated and analyzed in order to find the links between the exposure to physical factors under study and the parameters of the immune and neuroendocrine systems. Results: The indoor air study showed differences in the number and charge of air ions between the gymnasium with its numerous e-learning tools and the school of comparison. The study of the immune and neuroendocrine systems in the exposed group revealed age-related changes in the expression of lymphocyte subpopulations, moderate changes in humoral and phagocytic parameters, an imbalance in the expression of pro- and anti-inflammatory cytokines and hormones. The construction of logistic regression models allowed us to establish the link between the parameters of electromagnetic radiation in the school environment and changes in the immune status of students (CD19+ and CD3+CD8+ lymphocytes). Conclusion: The study demonstrated a number of changes in the regulatory systems of schoolchildren associated with the impact of physical factors of the school environment.