Method for predicting, regulating and controlling pollutant concentration level in closed space

Abstract

The invention discloses a method for predicting, regulating and controlling the concentration level of pollutants in a closed space, which comprises the following steps of: determining concerned closed space, pollutants and pollution sources, determining the release area and the release intensity of each pollution source, calculating the total source intensity and the pollutant concentration, and calculating the concentration level of the pollutants in the closed space. The release intensity, the release area, the fresh air exchange volume or the total source intensity of the specific pollution source are reversely deduced based on known parameters; and quantitative analysis and regulation of the pollutants in the closed space are realized through formulas S = sigma qiFi, C = S / V and a derivation formula. The method overcomes the limitation of traditional field measurement and CFD simulation, has the characteristics of being clear in theory and simple and convenient to operate, and can be widely applied to air quality control and evaluation of closed spaces such as traffic tools, civil buildings and industrial facilities; and a feasible technical basis is provided for reducing the risk that personnel are in contact with pollutants and improving the design and operation strategy of a ventilation system.

Description

Technical Field

[0001] The present invention relates to the technical field of spatial pollutant prediction and control, and specifically to a method for predicting and controlling pollutant concentration levels in a closed space. Background Art

[0002] With the continuous development of society and the acceleration of urbanization, people are spending more and more time living and working in enclosed spaces. For example, they live and work indoors, and even travel in "mobile homes." Buildings and vehicles often have typical characteristics such as closed structures, limited ventilation, and dense populations, leading to increasingly serious air pollution problems within them. This phenomenon affects the quality of life for residents, the work efficiency for workers, and the driving safety for drivers. Therefore, engineers and researchers have conducted extensive research on the air quality issues in enclosed spaces.

[0003] Literature 1 [Huang Jinxu, Zhang Jianpeng, Pan Shangxia, et al. Impact of passenger flow and outdoor environment on subway air quality [J]. Journal of Environmental Health, 2015, 5(03): 252-256] conducted a systematic investigation of the spatial layout of subway station entrances and exits and their relationship to bus stations. The study found that: Exhaust gas from external motor vehicles can enter the subway station interior through the entrances and exits, causing pollutants such as NO2 to accumulate excessively in areas with poor ventilation, making the pollution problem particularly prominent. The article points out that the layout of station ventilation systems and the optimization of entrance and exit locations are fundamental strategies for improving indoor air quality in rail transit.

[0004] Literature 2 [Liu Yongping, Zhang Lijun, Su Jin. Sampling monitoring of air quality in public areas of Shanghai subway stations [J]. Shanghai Preventive Medicine, 2022, 34(10): 1007-1013.] Air quality monitoring was conducted in the station halls, platforms, carriages and fresh air shafts of three underground stations on Shanghai Metro Line 9. The results showed that the relative humidity exceeded the standard rate by 66.7%, and the PM2.5 level at some stations in autumn and winter was 1.177, 1.247 and 1.171 respectively. 10 The exceedance rate was 20.6%, while other indicators generally met national standards. Spatially, CO2 levels and wind speeds were high in train compartments, and particulate matter and fungal levels in the fresh air shaft were significantly elevated. Seasonally, particulate matter concentrations were high in winter, while microbial concentrations were high in summer. Regression analysis showed that air quality was significantly influenced by temperature, humidity, season, and monitoring area, exhibiting distinct temporal and spatial distribution patterns. It is recommended that control strategies be tailored to local conditions and developed comprehensively.

[0005] Reference 3 [Wu Fan, Hu Changlin, Xu Renze, et al. Droplet propagation patterns and ventilation control strategies in high-speed train passenger compartments [J]. Journal of Railway Science and Engineering, 2024, 21(12): 4872-4884.] Based on a discrete phase model, a numerical simulation method for droplet diffusion in high-speed train passenger compartments was constructed and verified through actual vehicle tests. The results showed that small-particle droplets easily diffuse with airflow, and the propagation range is significantly affected by the distance between the release position and the return air outlet. When the top-to-sidewall air supply ratio is 1:3, the droplet accumulation can be reduced by 57.4%, and the deposition on passenger surfaces can be reduced by 34.0%. This study provides a theoretical basis for optimizing train ventilation systems and reducing the risk of respiratory infections.

[0006] Reference 4 [Yu Dezhuang, Wu Fan, Xu Renze, et al. Experimental Study on Purification Strategies for Multi-Source Particle Pollutants in Subway Passenger Compartments [J / OL]. Journal of Railway Science and Engineering, 1-10 [2025-07-25]] shows that due to the relatively uniform flow field within the carriage, particulate matter can quickly diffuse throughout the entire space, with a concentration difference of less than 20% between the two ends. However, surface deposition significantly increases the difficulty of cleaning and maintenance. Regarding air purification technologies, strong electric field dielectric technology achieved removal efficiencies of 59.4% and 80% for microbial aerosols and non-biological particulate matter, respectively, while cold plasma technology achieved removal efficiencies of 45% and 90%, respectively. While combining these two technologies can further improve air quality, the synergistic effect is limited. These research results provide important insights for optimizing the design and operation strategies of subway air conditioning systems and are of great value for improving carriage air quality. The study also points out that further research is needed on the mechanisms of particle deposition and long-term purification solutions.

[0007] Reference 5 [Chen Xu. Simulation Study on the Effect of Airflow Organization on Pollutant Dispersion in Subway Cars [J]. Heating, Ventilation and Air Conditioning, 2024, 54(S2): 392-399.] analyzed the impact of different air supply conditions on infection probability during peak hours through numerical simulation and orthogonal experiments. The results showed that increasing the air supply velocity significantly reduced the infection risk, while simply adjusting the air supply angle had limited effect. Increasing the ratio of supply / return air vents, while reducing the infection probability, also led to the spread of pollutants from the door area to the seating area. Orthogonal experiments showed that optimizing the air supply and exhaust pattern was the most effective means of controlling infection risk, followed by increasing the air supply velocity, and adjusting the air supply angle had the least effect. For Type B subway trains, the optimal air supply scheme was: an S2H2 air supply and exhaust pattern, a 60° air supply angle, and an air supply velocity of 2.4 m / s. This study provides important reference for the design of subway car air conditioning systems.

[0008] Reference 6 [Li Tian, ​​Wu Songbo, Zhang Jiye. Effects of Air Supply Methods on Ventilation and Diffusion Characteristics of Respiratory Pollutants on High-Speed ​​Trains [J]. Journal of Southwest Jiaotong University, 2024, 59(01): 94-103.] A full-scale carriage model was established based on CFD theory. Six air supply schemes were compared and analyzed for their effects on ventilation performance and pollutant diffusion, focusing on the upper window exhaust method. The results showed that optimizing air flow distribution improved airflow uniformity; while lower-level air supply increased energy utilization coefficient (1.38) and ventilation efficiency (1.21), it also reduced comfort. The study found that pollutants exhaled by passengers in train C easily diffused to train B. Using a localized porous ceiling to supply air reduced the pollutant concentration to 0.0019, effectively reducing the risk of cross-infection. This study provides important evidence for optimizing train ventilation systems.

[0009] Literature 7 [Wang Zongchang, Zhou Xinxi, Ma Bingbing, et al. Propagation characteristics and purification effects of air pollutants in high-speed train passenger compartments [J]. Acta Aerodynamica Sinica, 2022, 40(02): 138-145.] found through on-board experiments that solid particles generated in the middle of the passenger compartment lead to increased pollutant concentrations in the upper, middle, and downstream regions, with the largest increase in the downstream region. Top airflow is more effective than bottom airflow in suppressing pollutant diffusion. The experiments also verified that electrostatic precipitation and dielectric barrier discharge technologies can significantly improve purification efficiency, with electrostatic precipitation performing better, and its efficiency is positively correlated with pollutant concentration.

[0010] In summary, past research has achieved considerable success through field measurements and simulations, providing a theoretical basis and practical experience for controlling indoor air pollution in enclosed spaces. However, relatively little theoretical research exists on the control of indoor air pollution in enclosed spaces and the prediction of pollutant concentrations before and after control. Therefore, there is an urgent need to establish a simple and effective method for controlling and assessing air pollution in enclosed spaces. This will provide technical support for reducing pollutant concentrations in enclosed spaces, optimizing building or vehicle ventilation design, and improving the comfort, health, and safety of residents and passengers. Summary of the Invention

[0011] The present invention provides a method for predicting and regulating pollutant concentration levels in enclosed spaces. The method aims to guide the control and prediction of pollutant concentrations in various enclosed spaces, provide control requirements for the pollution source strength of various materials, improve the air quality in buildings or vehicles, reduce pollutant exposure levels, and protect the life, health, and public safety of residents or passengers.

[0012] The present invention is achieved through the following technical solutions:

[0013] A method for predicting and controlling pollutant concentration levels in a closed space, comprising the following steps:

[0014] S1. Identify the enclosed space of concern;

[0015] S2. Identify contaminants of concern within the enclosed space;

[0016] S3. Identify the sources of the pollutants of concern within the space of concern;

[0017] S4. Determine the release area of ​​each pollution source within the space of concern;

[0018] S5. Determine the release intensity of each pollution source within the space of concern;

[0019] S6. Calculate the total source intensity of the pollutants of concern within the space of concern;

[0020] S7. Determine the fresh air exchange rate for the space of interest;

[0021] S8. Calculate the concentration of the pollutant of concern in the space of concern;

[0022] S9. If the concentration, total source intensity, release area, and fresh air exchange rate of the pollutant of interest within the space of interest are known, calculate the release intensity of a particular pollution source;

[0023] S10. If the concentration, total source strength, release intensity, and fresh air exchange rate of the pollutant of interest within the space of interest are known, calculate the release area of ​​a particular pollution source;

[0024] S11. If the concentration and total source strength of the pollutant of interest in the space of interest are known, calculate the fresh air exchange rate for the space of interest;

[0025] S12. If the fresh air exchange rate and concentration of the pollutant of interest in the space of interest are known, calculate the total source intensity of the pollutant in the space of interest;

[0026] Preferably, the calculation of the total source intensity of the pollutants of interest in the space of interest in step S6 includes the following:

[0027] S=Σq i F i ;

[0028] S——total source intensity of pollutants, kg / s;

[0029] q i ——The release intensity of the pollutant from the i-th pollution source, kg / (m 2 s);

[0030] F i ——The release area of ​​the pollutant from the i-th pollution source, m 2 ;

[0031] Preferably, the calculation of the concentration of the pollutant of interest in the space of interest in step S8 includes the following:

[0032] C=S / V;

[0033] C——Concentration of pollutants of concern, kg / m 3 ;

[0034] V——Focus on the fresh air ventilation volume of the space, m 3 / s;

[0035] Preferably, the calculation of the release intensity of a pollution source in step S9 includes the following:

[0036] q i =(CV-Σq n F n ) / F i ;

[0037] q n ——Release intensity of pollutants from other pollution sources, kg / (m 2 s);

[0038] F n ——Release area of ​​pollutants from other pollution sources, m 2 ;

[0039] Preferably, the calculation of the release area of ​​a pollution source in step S10 includes the following:

[0040] F i =(CV-Σq n F n ) / q i ;

[0041] Preferably, the calculation of the fresh air ventilation volume of the space of interest in step S11 includes the following:

[0042] V=S / C;

[0043] Preferably, the calculation of the total source intensity of pollutants in the space of interest in step S12 includes the following:

[0044] S=CV.

[0045] Due to the adoption of the above technical solution, the present invention has the following beneficial effects:

[0046] In the past, research on air pollution in enclosed spaces primarily used field measurements and CFD simulations. Field measurements can only be used for completed projects, consuming manpower and material resources, and making it difficult to trace the source and provide corresponding control solutions. While CFD simulation can be used for proposed projects, it requires complex knowledge of fluid mechanics. The present invention provides a method for predicting and regulating pollutant concentration levels in enclosed spaces. It has clear theory and simple formulas, and can be used to predict the concentration levels of air pollutants in various enclosed spaces. It can also provide control standards for the release intensity of each pollution source and guide engineering technicians on which adjustment strategies and control standards to make to meet pollutant concentration requirements. The present invention can be used not only for indoor air quality control and assessment in the field of transportation, but also for the control and assessment of indoor air quality in enclosed spaces in other civil, industrial, and agricultural and animal husbandry fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 It is a schematic diagram of the steps of the present invention. DETAILED DESCRIPTION

[0048] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0049] like Figure 1 As shown,

[0050] Example 1: Formaldehyde concentration prediction in the middle carriage of a Beijing subway line before control

[0051] S1. Identify enclosed spaces of concern within a vehicle;

[0052] The middle carriage of a train on a Beijing subway line;

[0053] S2. Identify pollutants of concern within the enclosed spaces of vehicles;

[0054] formaldehyde;

[0055] S3. Identify the sources of the pollutants of concern within the space of concern;

[0056] Seats, floors, ceilings, side walls, gaps between side walls and roofs, doors, and end walls;

[0057] S4. Determine the release area of ​​each pollution source within the space of concern;

[0058] Seats 25.38m 2 、Floor 46.83m 2 、Ceiling 32.71m 2 、Side wall 31.58m 2 , the gap between the side wall and the roof is 0.63m 2、Door 19.37m 2 、End wall 5.16m 2 ;

[0059] S5. Determine the release intensity of each pollution source within the space of concern;

[0060] Seat 0.003915 μg / (m 2 ·s), floor 0.000095 μg / (m 2 ·s), ceiling 0.000558 μg / (m 2 ·s), sidewall 0.004322 μg / (m 2 ·s), gap between side wall and roof 0.062442 μg / (m 2 ·s), gate 0.000008 μg / (m 2 ·s), end wall 0.005403 μg / (m 2 s);

[0061] S6. Calculate the total source intensity of the pollutants of concern within the space of concern;

[0062] S=Σq i Fi = (0.003915 μg / (m 2 ·s)×25.38m 2 +0.000095 μg / (m 2 ·s)×46.83m 2 +0.000558 μg / (m 2 ·s)×32.71m 2 +0.004322 μg / (m 2 ·s)×31.58m 2 +0.062442 μg / (m 2 ·s)×0.63m 2 +0.000008 μg / (m 2 ·s)×19.37m 2 +0.005403 μg / (m 2 ·s)×5.16m 2 =0.3259 μg / s;

[0063] S7. Determine the fresh air exchange rate for the space of interest;

[0064] Fresh air ventilation volume 0.65m 3 / s;

[0065] S8. Calculate the concentration of the pollutant of concern in the space of concern;

[0066] C=S / V=0.3259 μg / s÷0.65m3 / s=0.5014μg / m 3 ;

[0067] Example 2: For the middle compartment described in Example 1, if the formaldehyde concentration needs to be reduced to 80% and the release intensity of other source items remains unchanged, to what limit should the formaldehyde release intensity of the side wall be reduced?

[0068] q i =(CV-Σq n F n ) / F i =[0.5014μg / m 3 ×80%×0.65m 3 / s-(0.003915 μg / (m 2 ·s)×25.38m 2 +0.000095 μg / (m 2 ·s)×46.83m 2 +0.000558 μg / (m 2 ·s)×32.71m 2 +0.062442 μg / (m 2 ·s)×0.63m 2 +0.000008 μg / (m 2 ·s)×19.37m 2 +0.005403 μg / (m 2 ·s)×5.16m 2 )] / 31.58m 2 =0.002259 μg / (m 2 s);

[0069] The formaldehyde emission intensity of the side wall should be reduced to 0.002259 μg / (m 2 ·s).

[0070] Example 3: For the middle compartment described in Example 1, if the formaldehyde concentration needs to be reduced to 80% and the release intensity of each source item remains unchanged, to what limit should the fresh air ventilation volume be adjusted?

[0071] V=S / C=0.3259 μg / s÷(0.5014μg / m 3 ×80%)=0.8125m 3 / s;

[0072] The fresh air ventilation volume should be adjusted to 0.8125m 3 / s.

[0073] Although the specific embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by ordinary technicians in this field, various changes can be made without departing from the purpose of the present invention. Modifications or deformations that do not involve creative work are still within the scope of protection of the present invention.

Claims

1. A method for predicting and controlling pollutant concentration levels in a closed space, characterized in that: The steps include: S1. Identify the enclosed space of concern; S2. Identify contaminants of concern within the enclosed space; S3. Identify the sources of the pollutants of concern within the space of concern; S4. Determine the release area of ​​each pollution source within the space of concern; S5. Determine the release intensity of each pollution source within the space of concern; S6. Calculate the total source intensity of the pollutants of concern within the space of concern; S7. Determine the fresh air exchange rate for the space of interest; S8. Calculate the concentration of the pollutant of concern in the space of concern; S9. If the concentration, total source intensity, release area, and fresh air exchange rate of the pollutant of interest within the space of interest are known, calculate the release intensity of a particular pollution source; S10. If the concentration, total source strength, release intensity, and fresh air exchange rate of the pollutant of interest within the space of interest are known, calculate the release area of ​​a particular pollution source; S11. If the concentration and total source strength of the pollutant of interest in the space of interest are known, calculate the fresh air exchange rate for the space of interest; S12. If the fresh air ventilation volume and concentration of the pollutants of interest in the space of interest are known, calculate the total source intensity of the pollutants in the space of interest.

2. The method for predicting and controlling pollutant concentration levels in a closed space according to claim 1, characterized in that: The calculation of the total source intensity of the pollutants of interest in the space of interest in step S6 includes the following: S=Σq i F i S——total source intensity of pollutants, kg / s; q i ——The release intensity of the pollutant from the i-th pollution source, kg / (m 2 s); F i ——The release area of ​​the pollutant from the i-th pollution source, m 2 .

3. The method for predicting and controlling pollutant concentration levels in a closed space according to claim 1, characterized in that: The calculation of the concentration of the pollutant of interest in the space of interest in step S8 includes the following: C=S / V C——Concentration of pollutants of concern, kg / m 3 ; V——Focus on the fresh air ventilation volume of the space, m 3 / s.

4. The method for predicting and controlling pollutant concentration levels in a closed space according to claim 1, characterized in that: The calculation of the release intensity of a pollution source in step S9 includes the following: q i =(CV-Σq n F n ) / F i q n ——Release intensity of pollutants from other pollution sources, kg / (m 2 s); F n ——Release area of ​​pollutants from other pollution sources, m 2 .

5. The method for predicting and controlling pollutant concentration levels in a closed space according to claim 1, characterized in that: The calculation of the release area of ​​a pollution source in step S10 includes the following: F i =(CV-Σq n F n ) / q i 。 6. The method for predicting and controlling pollutant concentration levels in a closed space according to claim 1, characterized in that: The calculation of the fresh air ventilation volume of the space of interest in step S11 includes the following: V=S / C.

7. The method for predicting and controlling pollutant concentration levels in a closed space according to claim 1, characterized in that: The calculation of the total source intensity of pollutants in the space of interest in step S12 includes the following: S=CV.

8. The method for predicting and controlling pollutant concentration levels in a closed space according to claim 1, characterized in that: The enclosed space includes one or more of the following: indoor spaces of civil buildings, subway cars, high-speed rail passenger compartments, car cabs, industrial plants, and agricultural and animal husbandry sheds.

9. The method for predicting and controlling pollutant concentration levels in a closed space according to claim 1, characterized in that: The pollutants of concern include formaldehyde.

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