Healthy Indoor Air Research Articles

5.X.2. Improving indoor air quality: a public health challenge

Abstract Indoor air quality (IAQ) may have a profound effect on a person’s physical and mental health and well-being. The Knowledge for Indoor Air Quality and Health (K-HEALTHinAIR) project (grant no 101057693) is an interdisciplinary European research project that brings together 15 partners across 8 countries to study the sources, determinants and health outcomes related to IAQ. We aim to increase knowledge and provide input for more accurate monitoring and interventions, promoting healthy indoor air quality across several public health settings. The main aim of this workshop is to engage the public health community in the relevance of IAQ as a public health concern. We will share the innovative and new methodologies applied in the K-HEALTHinAIR project to study IAQ and health and discuss opportunities as well as challenges in this field of research to support shared learning. This workshop highlights IAQ pollutant sources and determinants, seasonal variation in IAQ, older people’s IAQ and health, and presents the project’s open access platform that is developed to share knowledge. We will zoom in on the evidence available for the sources and determinants of exposure to indoor air pollutants. This activity, a systematic review, was fundamental to identify the gaps of knowledge and guide the preparation of data collection tools. It also depicts the main pollutants present in indoor settings and the respective sources and determinants of exposure. Then, one of the 9 public health scenarios studied in the project is presented. We will focus on the first results regarding (determinants of) IAQ variation in primary schools at several locations in Poland. Next, the pilot study in older people living in senior homes in the Netherlands presents first findings of IAQ and health data in this vulnerable population. Finally, the project will deliver an open-access platform aiming to be the one-stop-shop for IAQ Knowledge. The user-profiles identified are presented. At the end, the workshop participants will be up to date on the project’s activities, its relevance for public health and the open access platform via which all output will be shared. Participants will leave with increased understanding of public health research needed to further study IAQ and its impact on health and well-being. Key messages • Indoor air quality is a public health concern impacting health and well-being, especially in vulnerable populations such as children and older people. • The K-HEALTHinAIR project is a multidisciplinary research project in which innovative methodologies are applied to increase knowledge on indoor air quality and health.

SMAP: Design And Development Of A Sustainable Modular Air Purifier For Energy-Efficient Indoor Air Quality Management

This paper presents the design and development of the Sustainable Modular Air Purifier (SMAP), an innovative solution aimed at improving indoor air quality while minimizing energy consumption. The system features a modular architecture that allows for customizable and targeted air purification based on specific pollutants, including particulate matter, mold spores, and animal dander. Each module is equipped with specialized filters—high-efficiency particulate air, UV-C sterilization, and activated carbon—and operates selectively based on real-time air quality data from advanced sensors. This intelligent activation mechanism is aimed to reduce energy consumption, thus enhancing the system’s sustainability. Its modularity also allows for easy maintenance and adaptability to different indoor environments, making it scalable to a variety of use cases. Through a combination of energy-efficient components and a user-friendly interface, the SMAP ensures high purification efficiency and also contributes to the broader goal of environmental sustainability. The system’s performance, flexibility, and low energy footprint offer a promising solution for maintaining healthy indoor air quality in an environmentally responsible manner

Advances in Electrostatic Plasma Methods for Purification of Airborne Pathogenic Microbial Aerosols: Mechanism, Modeling and Application.

The transmission of pathogenic airborne microorganisms significantly impacts public health and societal functioning. Ensuring healthy indoor air quality in public spaces is critical. Among various air purification technologies, electrostatic precipitation and atmospheric pressure nonthermal plasma are notable for their broad-spectrum effectiveness, high efficiency, cost-effectiveness, and safety. This review investigates the primary mechanisms by which these electrostatic methods collect and disinfect pathogenic aerosols. It also delves into recent advancements in enhancing their physical and chemical mechanisms for improve efficiency. Simultaneously, a thorough summary of mathematical models related to the migration and deactivation of pathogenic aerosols in electrostatic purifiers is provided. It will help us to understand the behavior of aerosols in purification systems. Additionally, the review discusses the current research on creating a comprehensive health protection system and addresses the challenges of balancing byproduct control with efficiency. The aim is to establish a foundation for future research and development in electrostatic aerosol purification and develop integrated air purification technologies that are both efficient and safe.

The relationship between occupant behaviour and indoor air quality in Malaysian hospital outpatient departments: A multistage cross-sectional study

IntroductionPoor indoor air quality (IAQ) in healthcare settings may adversely impact occupants’ well-being and promote transmission of infectious respiratory disease. However, evidence on its potentially modifiable determinants, including occupant behaviour, remains scarce. This study aims to determine the relationship between occupant behaviour and IAQ in Malaysian hospital outpatient departments (OPDs). MethodsA multistage cross-sectional study of six randomly selected Malaysian public hospital OPDs was conducted. In stage one, IAQ parameters, including temperature, relative humidity (RH), air velocity (AV), carbon dioxide (CO2), total bacterial count (TBC), and total fungal count (TFC) were measured. In stage two, an observation form based on the Korsavi and Montazami tool for measuring adaptive behaviour was used to examine occupant density, activities, and operation of building envelopes and appliances. Simple correlation, partial correlation, and linear regression analyses were performed to examine the relationship between occupant behaviour and IAQ parameters. ResultsThe IAQ of selected hospital OPDs complied with established standards, except for temperature and AV. Occupant density was positively correlated with temperature and CO2. Meanwhile, occupants' activities including slow walking and brisk walking were positively correlated with temperature, AV, CO2, TBC and TFC. Conversely, occupants' opening of windows and doors were positively correlated with temperature and AV but negatively correlated with CO2, TBC and TFC. Finally, turning on fans was positively correlated with AV but negatively correlated with TBC, whereas turning on air conditioner was positively correlated with CO2. Among occupants’ behaviour, opening of windows and doors contributed the most to variation in IAQ parameters. ConclusionsThe study findings suggest that IAQ in hospital OPDs are influenced by occupant density, activities, and operation of doors, windows, and appliances. Prospective hospital IAQ guidelines should incorporate policies and measures targeting these factors to ensure occupants’ best practices in maintaining healthy hospital indoor air environments.

New Methodology to Evaluate and Optimize Indoor Ventilation Based on Rapid Response Sensors.

The recent pandemic increased attention to the need for appropriated ventilation and good air quality as efficient measures to achieve safe and healthy indoor air. This work provides a novel methodology for continuously evaluating ventilation in public areas using modern rapid response sensors (RRS). This methodology innovatively assesses the ventilation of a space by combining a quantitative estimation of the real air exchange in the space-obtained from CO2 experimental RRS measurements and the characteristics of and activity in the space-and indoor and outdoor RRS measurements of other pollutants, with healthy recommendations from different organisations. The methodology allows space managers to easily evaluate, in a continuous form, the appropriateness of their ventilation strategy, thanks to modern RRS measurements and direct calculations (implemented here in a web app), even in situations of full activity. The methodology improves on the existing standards, which imply the release of tracer gases and expert intervention, and could also be used to set a control system that measures continuously and adapts the ventilation to changes in indoor occupancy and activity, guaranteeing safe and healthy air in an energy-efficient way. Sample public concurrence spaces with different conditions are used to illustrate the methodology.

Association Between Air Microbiological Exposure With Sick Building Syndrome (SBS) among College Dormitory Students in Public University

Introduction: Microbiological pollutants in indoor air can lead to sick building syndrome (SBS). A conducive academic environment in university dormitories requires healthy indoor air quality to enhance student performance. This study aimed to determine the association between indoor air microbiological exposure and SBS among college dormitory students at a public university. Methods: A cross-sectional study was conducted among 112 male and female college dormitory students who stayed in the public university dormitory for more than three months. Respondents were given a self-administered questionnaire-based NIOSH Indoor Environmental Quality Survey. 14 houses were selected for the measurement of indoor air quality which included PM2.5, PM10, relative humidity (%), temperature (°C), air velocity (m/s), indoor bacterial concentration (cfu/m3), and indoor mould concentration (cfu/m3). Results: Higher percentages of SBS symptoms were reported among female (94.6%) college dormitory students compared to male (82.1%). A significant difference in itching symptom on the arms and forearms was found among individuals of different genders (p<0.05). Indoor air parameters such as temperature (OR = 2.56, 95% CI = 2.66-9.87), relative humidity (OR = 1.77, 95% CI = 1.54 – 5.79), indoor bacteria concentration (OR=2.28, 95% CI = 2.48 – 10.93), and indoor mould concentration (OR=2.59, 95% CI = 1.75 – 8.98) were significantly associated with the recent SBS symptoms. Multiple logistic regression showed that the most significant predictor of SBS was indoor mould concentration. Conclusion: Exposure to high concentrations of indoor bacteria and mould, high temperatures, and high relative humidity influenced the prevalence of SBS among college dormitory students. Further assessment and preventive action need to be taken to reduce the exposure of indoor air microbiological to the students.

Novel wall-attached multidirectional jets: Mathematical formulation, CFD modeling and experimental validation

Achieving a healthy and comfortable indoor air environment has long been an objective of human endeavors. For a novel ventilation system, the wall-attached multidirectional jet pattern, the mathematical model describing the jet trajectory, temperature and velocity changes was first proposed to predict airflow attachment and separation moments from walls, covering a densimetric Froude number range from 0.5 to 4.0. Subsequently, this mathematical model was solved using a comprehensive numerical methodology and validated by full-scale experiments, which demonstrated that this established model could accurately depict the wall-attached multidirectional jet flow, with controllable errors — 16.4% for jet trajectory and 8.2% errors for jet axis temperature — when maintaining a supply velocity of 0.2 m/s. Also, the flow characteristics within a room featuring internal heat sources were analyzed, varying air supply velocities from 0.1 to 0.8 m/s and jet angles from 0° to 60°. Finally, this flow pattern of the wall-attached multidirectional jet was further confirmed and reproduced through CFD modelling which illustrated temperature stratification ranging from 18.1 °C to 25.2 °C, similar to the pattern observed in displacement ventilation. Present research could be valuable for the development of wall-attached multidirectional jet and the establishment of a healthy indoor air environment in practical applications.

Estimation of Natural Ventilation Rates in an Office Room with 145 mm-Diameter Circular Openings Using the Occupant-Generated Tracer-Gas Method

Natural ventilation in a building is an effective way to achieve acceptable indoor air quality. Ventilation dilutes contaminants such as bioeffluents generated by occupants, substances emitted from building materials, and the water vapor generated by occupants’ activities. In a building that requires heating and cooling, adequate ventilation is crucial to minimize energy consumption while maintaining healthy indoor air quality. However, measuring the actual magnitude of the natural ventilation rate, including infiltration through the building envelope and airflow through the building openings, is not always feasible. Although international and national standards suggested the required ventilation rates to maintain acceptable indoor air quality in buildings, they did not offer action plans to achieve or evaluate those design ventilation rates in buildings in use. In this study, the occupant-generated carbon dioxide (CO2) tracer gas decay method was applied to estimate the ventilation rates in an office room in Seoul, South Korea, from summer to winter. Using the method, real-time ventilation rates can be calculated by monitoring indoor and outdoor CO2 concentrations without injecting a tracer gas. For natural ventilation in the test room, 145 mm-diameter circular openings on the fixed glass were used. As a result, first, the indoor CO2 concentrations were used as an indicator to evaluate how much the indoor air quality deteriorated when all the windows were closed in an occupied office room compared to the international standards for indoor air quality. Moreover, we found out that the estimated ventilation rates varied depending on various environmental conditions, even with the same openings for natural ventilation. Considering the indoor and outdoor temperature differences and outdoor wind speeds as the main factors influencing the ventilation rates, we analyzed how they affected the ventilation rates in the different seasons of South Korea. When the wind speeds were calm, less than 2 m/s, the temperature difference played as a factor that influenced the estimated ventilation rates. On the other hand, when the temperature differences were low, less than 3 °C, the wind speed was the primary factor. This study raises awareness about the risk of poor indoor air quality in office rooms that could lead to health problems or unpleasant working environments. This study presents an example of estimating the ventilation rates in an existing building. By using the presented method, the ventilation rate in an existing building can be simply estimated while using the building as usual, and appropriate ventilation strategies for the building can be determined to maintain the desired indoor air quality.

Influence of air ceiling diffusers in enclosed spaces: An experimental and numerical investigation

Within the past few years, IEQ has been a hot topic among building occupants, government officials, and academics all around the globe. Most modern life is spent indoors, in homes, workplaces, and shopping centres. People’s awareness of the need for healthy indoor air quality (IAQ) rises in tandem with their rising standard of living. Along with air temperature, humidity, and cleanliness, air velocity in a climate-controlled room affects the space’s microclimate. In particular, reducing discomfort in enclosed areas is a function of having an adequate distribution of air velocities. This study employs computational fluid dynamics (CFD) models to examine the effects of types of air diffusers in an enclosed office space in Alexandria, Egypt, on the ensuing air velocities and temperature gradients. Model accuracy has been confirmed by comparing numerical simulations to physical measurements. The simulations demonstrated that the square diffuser was superior in temperature distribution uniformity within the office volume but that there was a significant interaction between supply diffusers. The round diffuser had faster velocities in the standing and sitting planes (1.2 and 1.8 m) and a lower average temperature, implying that it can be employed with a reduced fan speed than the square diffuser, reducing overall power use.

Assessment of indoor air quality and comfort by comparing an energy simulation and actual data in Native American shelters

Introduction: This research will determine if a native American shelter (wigwam) can create comfort and if while doing so can provide healthy indoor air quality (IAQ) levels as defined by current standards. Concurrent to this research a technique to digitally model the outcomes of comfort created within the shelter was developed.Methods: A fullsize example of a wigwam was built and data from inside and outside the wigwam monitored for comparison. Data collected both inside and outside was temperature and relative humidity of the air, collected inside the wigwam were CO2, VOC, and PM2.5 levels. The wigwam allowed us to compare the accuracy of a digital model created in Design Builder. The Design Builder model was made to the specific size, materials, and location of the actual wigwam. This allowed an accurate comparison of temperature and relative humidity levels. Design-Builder accurately recreated the attributes of the full-size wigwam.Results and Discussion: It was found that comfort can be achieved to modern standards in this native shelter; as temperature, relative humidity, and rainfall exposure can all be controlled to acceptable levels. Indoor air quality is always at an acceptable level when a fire isn’t active. When an open fire is introduced, the particulates and VOC released into the interior of the wigwam are at dangerous levels. A woodstove with flue pipe allowed for comfort to be maintained at healthier air quality levels but did not reach acceptable levels for particulate matter.

Healthy Residential Indoor Air Quality

Healthy indoor environments are important components of sustainable housing. Creating such environments means avoiding health hazards from mold and other allergens, combustion pollutants, volatile organic compounds, radon, lead, and asbestos. Ways of doing so include use of water-managed building foundations, site drainage, adequate ventilation, informed selection of equipment for space conditioning and water heating, material choices, and sub-slab ventilation. Lead and asbestos are concerns in rehabilitating older homes and are addressed through well-established best practices. The purpose of this paper is to examine indoor environmental pollutants, their impacts on human health, and methods to avoid and mitigate exposure. The presence of asthma triggers in homes has become an increasingly serious indoor environmental issue and will be covered in more depth.

Mitigation Methods of Sick Building Syndrome With an Emphasis on Indoor Height Setting

The condition of the space environment as a result of the interaction of physical, chemical, and biological factors, in a complex way, can have acute and chronic effects on the physical and psychological health of the occupants. This was the incidence of sick building syndrome, and efforts to reduce and eliminate the syndrome were presented in this case study. The aim was to produce healthy indoor quality and sustainable use by its occupants. The methods used minimum Indonesian standards regarding procedures for planning the housing environment in urban areas. The analysis of changes in the indoor volume employed indoor height variables for a particular floor area to apply flexibility to various building layouts. The variability of changes in the pollutant exposure area and indoor air volume was expressed as a relative change. Setting indoor height was a significant determinant for maintaining healthy indoor air quality through diluting air against pollutants. An additional 0.5 m of room height could increase the air volume by 15%-20% greater than the increase in the pollutant area. It was an effective method both at the design and building renovation stages. The physical and thermal mitigation was generally performed at the building use stage. Some of the conducted approaches included air conditioning (AC), electric or manual ventilation, and chemical-phytotechnological mitigation indoors by adding chemicals to space. The methods of indoor depollution during the use of buildings are still necessary using physical and chemical-phytotechnological methods by placing decorative plants.

Seasonal Air Quality in Bedrooms with Natural, Mechanical or Hybrid Ventilation Systems and Varied Window Opening Behavior-Field Measurement Results

The article presents the results of measurements of temperature, relative humidity and CO2 concentration in six single-family houses’ bedrooms located in Poland, in Wrocław and vicinity, during two climatic seasons: summer–autumn and winter. Two buildings with natural ventilation (NV) were tested, three with mechanical ventilation with heat recovery (MV) and one with hybrid ventilation (HV)—mixed mode natural and mechanical. The behavior of residents regarding opening windows was analyzed and the influence of the changing internal and external conditions on their active reactions was examined. The analysis confirms and adds to the global discourse on the key impact of user behavior on securing healthy indoor air quality in housing, regardless of ventilation system or building energy standard. A disconnect exists between the observed window opening practices and typical design principles, assuming adjustment to a given ventilation system or changing weather conditions. The observations showed that in both analyzed seasons it was possible to obtain a good quality internal environment, in terms of CO2 level, regardless of the ventilation system used in the building. However, unfavorable results were observed for one bedroom, in which the inhabitants do not adapt their behavior to local technical conditions. Taking into account the level of relative humidity (RH), much higher values were observed in the NV bedrooms in both analyzed periods. The obtained results were divided into IAQ classes in accordance with the EN 16798-1. The recorded values of the internal temperature confirm the significant influence of the location of the room in the building and the actions taken by the residents.

Impact of Covid-19 on Heating, Ventilation and Air - Conditioning Systems

People spend much of their lives indoors, so air quality is particularly important to their health, ability to work, and well-being. The COVID -19 pandemic has heightened people's awareness of the importance of maintaining high indoor air quality. Such an emergency has underscored the need for adequate heating, ventilation and air conditioning systems that can provide a good indoor air quality, especially ventilation systems as important players in preventing and reducing the risk of airborne infections. In this paper, we review natural and mechanical ventilation and their roles in dealing with coronavirus, focusing on key factors for healthy indoor air. Two pillars are critical for ventilation: increased air exchange rate and air filtration in ventilation systems.

Research status and prospects of indoor airborne microbiome based on respiratory health effects

<p indent="0mm">Indoor environment is an important repository of microbiome. Environmental microbiome can influence immune protection through changing the commensal flora of the respiratory tract. The interaction between environment airborne microbiome and human microbiome contributes to human microbial diversity, provides immunomodulatory effects, and thus reduces the risk of respiratory diseases. Lack of immune modulation acquired through microbial exposure may lead to risk of chronic respiratory diseases. Clinical parameters, such as susceptibility, progression, and severity of respiratory disease, are associated with microbial changes. Chronic obstructive pulmonary disease, cystic fibrosis, asthma, and lung cancers are associated with airway microbial dysbiosis. The changes of microbiome during the disease period are mainly characterized by a decrease in overall bacterial diversity, a decrease in the number of commensal bacteria, and an increase in the number of potential pathogenic bacteria. Based on the perception that pathogenic or conditional pathogenic microbiome is responsible for the infection and transmission of respiratory and non-respiratory diseases, public health policies have long favored keeping indoors at lower concentrations of microbiome or even absolutely sterile. However, in the past decade, an in-depth understanding of the microbiology of the environment and human health has shifted researchers’ view of indoor microbiome from a purely pathogenic and infectious negative role to a potentially protective, preventive positive role. Facing with the dual health effects of indoor airborne microbiome, the ideal control strategy should be to increase the microbial diversity and the proportion of beneficial microbiome, while reducing the concentration of pathogenic microbiome for regions, seasons, and sensitive populations. However, there is still no paradigm shift in built environment microbiology due to technical bottlenecks that prevent researchers from establishing a causal relationship between indoor microbiome and health effects. Currently, the types and properties of indoor airborne microbiome are yet to be fully screened and understood. The characteristics of indoor microbiome when they exert health effects are yet to quantify, including microbial metabolization and reproduction in the respiratory tract, corresponding protective effects, and dose-response effects and individual variation in health effects. The answer to the question “What is a healthy indoor air microbial environment”, that is, the characterization of indoor airborne microbiome based on respiratory health effects, is hindered by respiratory microbial sampling, in-depth analysis of microbial data, and the accuracy of <italic>in vitro</italic> experiments. Subsequent research needs to focus on the development of the following techniques: Microbial sampling tools with low invasiveness, high efficiency and low cost; statistical tools with complex source identification, interference factor quantification and causal relationship judgment functions; and experimental tools capable of simulating real, complex respiratory environments and revealing molecular mechanisms of action <italic>in vivo</italic>. “What is a healthy indoor air microbial environment” will gradually become clear as these questions are resolved. A clear and quantitative mechanism will serve as a scientific basis to guide the improvement of indoor microbial control standards and the rational use of practical interventions.

Healthy indoor air is our fundamental need: the time to act is now.

Healthy indoor air is our fundamental need: the time to act is now.

Indoor air quality level influence sick building syndrome among occupants in educational buildings

In educational facilities, good and healthy indoor air quality is critical to ensure students’ focus and academic activities can be carried out efficiently. The goal of this study was to evaluate the link between indoor air quality level with sick building syndrome and health complaints among occupants. A cross-sectional study was conducted which involved 513 occupants. A modified MM040Na questionnaire was used in this study. Occupants’ workspaces were monitored for indoor air quality. The score obtained from the questionnaire and environmental factors were tested using statistical analyses incorporating test of differences namely Chi–Square, t-test, and non-parametric analysis. Logistic regression was conducted to evaluate relationship between exposure and occupants’ complaint. Results shows that some indoor air pollutants (carbon dioxide, formaldehyde, and particulate matter) are related to overall sick building syndrome (Odd Ratio, OR=1.348, 2.493, 1.958 respectively). General score of sick building syndrome (SBS) shows significant relationship with air motion (OR=2.220) and air flow (OR=2.515). Mucosal score of SBS suggest exposure risk towards indoor factors namely formaldehyde (OR=2.799), while dermal effect was associated from the exposure of Particulate (OR=2.88), carbon dioxide (OR=4.000), and air flow (OR=2.679). In educational environments, indoor contaminants have an impact on reported symptoms.&lt;br /&gt;&lt;br /&gt;

The Rights to Health Of Worker From the Perspective of Indoor Air Quality

Indoor air quality really effects persons’ health, including workers whose time mostly spent at work. Persons’ conduct may create pollutant which effect indoor air quality. Unhealthy indoor air has caused more than four million people dead from pneumonia, stroke, systemic heart decease, obstructive lung decease and cancer. Persons’ conduct must be regulated by law to ensure one’s rights and obligation do not violate others. This research was focused on how the rights to health of the workers from the perspective of indoor air quality was protected by law and what obligations were generated from the rights towards workers, employers and the state. This research was an analytical descriptive doctrinal one using library research to gain secondary data from related legislation and regulation as well as expert commentaries in textbooks and scientific journal articles. To ensure indoor air quality for workers, the workers themselves and the employers must be equipped with the knowledge and comprehension of the rights they possess and the obligation attached with the rights to implement the law on how they have to conduct to ensure the participation in the availability of healthy indoor air quality. Workers and employers shall not act nor omit which might resulted in unhealthy indoor air at work room through ensuring fresh air circulation, avoiding smoke and other polluting substances use in indoor rooms.

Indoor Air Quality of Physical and Microbiological in Universitas Muhammadiyah Kalimantan Timur, Indonesia

Indoor air quality is important for mental health and a comfortable environment inside the rooms. Poor indoor air quality has an impact to the sick building syndrome in occupants in the rooms. Physical and microbiological are factors that influence indoor air quality. The purpose of this study is to measure indoor air temperature, humidity, and microbiology in Universitas Muhammadiyah Kalimantan Timur in the morning and afternoon. The method used field measurement, microbiological laboratory analysis, and regression test by SPSS. High temperature and microbiology occur in the afternoon, humidity is not significant between morning and afternoon. Temperature and humidity were influenced by ventilation and the use of air conditioners in the rooms. Ventilation, the efficiency of air circulation, building type, maintenance of air conditioner, and occupant density are factors in getting clean and healthy indoor air quality to keep a comfortable environment. The statistical analysis resulted that temperature and humidity have not affected the indoor air microbiological increase.

An evaluation model of indoor PM2.5 dynamic characteristics considering human activities

Healthy indoor air quality is a basic standard for a good living environment, the air exchange rate (a), particle penetration coefficient (p), and deposition rate (k) of indoor PM2.5 are the main parameters for the design of fresh air ventilation systems like air cleaning facilities. Accurate cleaning methods help to provide qualified indoor air quality and reduce energy consumption. However, most of the measurements and evaluations have been completed in an enclosed indoor environment that fails to consider the impact of indoor activities and lacks the personalization of cleaning methods. Therefore, parameters should not be fixed but dynamically set according to the size, function, and human activities of different indoor spaces. In order to provide dynamic parameters, this paper proposes an indoor PM2.5 dynamic characteristic evaluation model considering human activities based on the real-time monitoring data and the principle of mass conservations. First, the indoor dynamic equilibrium equation of PM2.5 under the influence of human activities was established, and the dynamic ranges of a, p, and k were obtained by solving differential equation groups. In addition, the indoor environment without human activities was used as the control group for analysis. The differences between the experimental and control groups were analyzed, and the validity of the model was verified based on the measured data. The experiment results showed that the fluctuations of p were relatively small (p = 0.9), and the fluctuations of a and k were large (a = 2.5 ± 2.26, k = 1.63 ± 2.07) in a natural ventilated indoor environment with human activities, which were different from the enclosed indoor environment. This study proposed the influence of human activities for the first time, which can provide a reference for the parameter design of indoor fresh air ventilation systems and provide technical support and decision-making service for the prediction of indoor PM2.5 under natural ventilation.