A method for evaluating the suitability of developing and utilizing a cave air environment

Abstract

The present application relates to the technical field of landscape evaluation, in particular to a cave air environment development and utilization suitability evaluation method, through setting multiple detection devices for detecting air environment indexes inside and outside the cave, the corresponding numerical curves of each detection index inside the cave, position, structure, environment and the like can be obtained, and through comparison and table statistics of each detection index, the development and utilization suitability of the air environment inside the cave is evaluated, the evaluation result and grading standard are made in combination with relevant standards, and scientific basis and reference value are provided for protecting the air environment, ecology and touring suitability and risk inside the cave.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of landscape assessment, in particular to a cave air environment development and utilization suitability assessment method. BACKGROUND

[0002] Cave air environment research is the basis of cave protection. Before cave development, air environment development and utilization suitability assessment should be carried out to evaluate whether it is suitable to carry out cave tour activities, so as to avoid the destruction of cave landscape resources.

[0003] At present, the research on tourist cave air environment in the prior art mainly focuses on cave climate environment, tourism activities and air self-purification capacity, and the technical method and theoretical research on cave air environment development and utilization suitability are relatively less.

[0004] Therefore, it is necessary to design a cave air environment development and utilization suitability assessment method to carry out air environment development and utilization suitability assessment research on the proposed development and utilization section, which can provide scientific reference for the protection and utilization of tourist caves in China. SUMMARY

[0005] The purpose of the present application is to overcome the shortcomings of the prior art, and provide a cave air environment development and utilization suitability assessment method to carry out air environment development and utilization suitability assessment research on the proposed development and utilization section, which can provide scientific reference for the protection and utilization of tourist caves.

[0006] In order to achieve the above purpose, the present application provides a cave air environment development and utilization suitability assessment method:

[0007] Comprising the following steps:

[0008] S1, using artificial patrol or fixed-point monitoring method, from the entrance to the exit of the cave in order, through the equipment on the multiple measuring points to detect the cave external and internal air environment evaluation series indexes; The indexes include air temperature, relative humidity, CO2 concentration, air positive and negative ions, air pressure and wind speed;

[0009] S2, establish the data change curve of each index at each measuring point, and determine the condition of each index in the cave through the curve;

[0010] S3, establish the air quality evaluation in the cave, and the calculation formula is:

[0011] P CI =(n - / 1000)×(1 / q);

[0012] Wherein, P CI is the air quality evaluation index, n -For air negative ion concentration, q is monopolar coefficient, namely the ratio of positive ion and negative ion in air;

[0013] Wherein q=n + / n - ; n + is air positive ion concentration, 1000 is air negative ion concentration meeting the minimum requirement of human body biological effect;

[0014] ;

[0015] S4, five classifications of air quality are made according to air quality evaluation index;

[0016] S5, the influence of CO2 concentration on air quality in cave is evaluated according to health standard;

[0017] S6, karst cave ecological environment capacity is calculated according to allowable concentration of cave CO2, and the calculation formula is:

[0018]

[0019] Wherein, E c is daily capacity of ecological tourism of development and utilization cave section, and the unit is person-time; c t is given CO2 target concentration or allowable concentration, and the unit is ppm; c0 is the maximum concentration of CO2 in measured cave air, and the unit is ppm; is the exhalation amount of CO2 per person in cave opening period, and the unit is L; V is the volume of cave, and the unit is m 3 .

[0020] The detection of CO2 concentration in the index is used for air quality evaluation of CO2 concentration and spatial distribution characteristics in cave.

[0021] The detection of air pressure in the index is used for evaluation of oxygen content in cave.

[0022] The detection of wind speed in the index is used for evaluation of the degree of closure of cave.

[0023] The detection of air positive and negative ions in the index is used for evaluation of air quality in cave.

[0024] The five classifications in S4 are as follows: A level is the cleanest CI>1.0; B level is general clean CI=1.0-0.7; C level is medium clean CI=0.69-0.50; D level is allowable CI=0.49-0.30; E level is critical value CI<0.30.

[0025] Compared with the prior art, the present application has the following beneficial effects:

[0026] The present application can obtain the numerical curve corresponding to the position, structure, environment, etc. of the cave interior by setting multiple detection devices for detecting air environment indexes inside and outside the cave, and making comparison and table statistics of various detection indexes, and further making evaluation on the development and utilization suitability of the air environment inside the cave, and making evaluation results and grading standards in combination with relevant standards, which provides scientific basis and reference value for protecting the cave interior landscape environment, ecology, and touring suitability and risk. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 The figure is a profile and plane schematic diagram of Da Cao Tiankeng-Red Rose Hall and a position diagram of index monitoring points of the embodiment of the present application.

[0028] Figure 2 The figure is a measurement record schematic diagram of various air environment parameters of the present application.

[0029] Figure 3 The figure is a schematic diagram of the change of temperature, humidity and carbon dioxide concentration in the cave with the position of monitoring points during the detection period of the present application.

[0030] Figure 4 The figure is a schematic diagram of the change of positive and negative ion concentration and its correlation coefficient in the cave with the position of monitoring points during the detection period of the present application.

[0031] Figure 5 The figure is a schematic diagram of air quality grading standards of the present application. DETAILED DESCRIPTION

[0032] Reference Figures 1-5 The present application will be further described in combination with the drawings:

[0033] The embodiment takes the cave system of Da Cao Tiankeng-Red Rose Hall as an example to measure the evaluation indexes such as air temperature, relative humidity, CO2 concentration, air positive and negative ions, air pressure and wind speed in the cave section to be developed and utilized.

[0034] As shown in Figure 1 , the test position sequence is Da Cao Tiankeng→Red Rose Hall→Tanjia Cave exit, and a total of 22 observation points are set, and the artificial patrol method is adopted, and the measurement results are shown in Figure 2 .

[0035] Air temperature:

[0036] Among them, the air temperature change in the development and utilization cave section is between 14.8℃ and 23.5℃ (see Figure 2 and Figure 3). Due to the frequent exchange with the outside air, the high value of the temperature in this test appeared in the top entrance of the cave (A observation point) and the exit of the Tanjia cave (V monitoring point), which were 23.5℃ and 19.6℃, respectively. Therefore, the average temperature of the cave was 17.2℃, which was basically consistent with the average temperature of the county (16.9℃). It can be seen from Figure 3 that the temperature was lower and tended to be stable as it went deeper into the cave to the vicinity of the Rose Hall (L-Q observation point). Therefore, the overall temperature curve showed a shape of high in the middle and low at both ends. Due to the air exchange in the middle part of the cave (wind speed 0.2m / s-1.1m / s), the temperature in this part was higher. However, overall, the development and utilization of the cave section was longer, and most of the cave section was relatively narrow. Therefore, the air exchange frequency inside and outside the cave was relatively small, and the overall temperature change was not large, with a change of less than 5℃.

[0037] Relative humidity:

[0038] The average relative humidity in the development and utilization section of the cave was 94.74% (see Figure 2 ) except for the values at the entrance of the fossil cave at the bottom of the cave and the entrance of the Tanjia cave. The humidity in the cave increased with the decrease of temperature as it went deeper into the cave to the vicinity of the Rose Hall (L-Q observation point). The humidity value changed little, and the change curve tended to be consistent. The humidity in the local section was close to 100% (see Figure 3 ), indicating that there were still a lot of water vapor sources in the cave, and the current small amount of human activity had little effect on the humidity in the cave.

[0039] CO2 concentration, air pressure and wind speed:

[0040] Considering that high CO2 concentration in the air can cause discomfort to tourists and staff who come to enjoy the view, and in severe cases, it can cause breathing difficulties and even death. In order to understand the spatial distribution characteristics of CO2 concentration in the air of the development cave section and make a preliminary evaluation of the air quality, the working group measured the CO2 concentration, and the results are shown in Figure 2 and Figure 3 . The CO2 content in the air of the cave changed greatly, ranging from 334ppm to 856ppm, with an average concentration of 625.82ppm, which was within the first-level health standard (<1000ppm);

[0041] The change of air pressure can affect the air flow and oxygen partial pressure in the cave, thereby affecting the oxygen content in the cave. The high or low oxygen content in the cave will affect the supply of oxygen in the human body during the future development of cave tourism activities, thereby affecting the psychological changes of the human body. The air pressure in the development and utilization section of the cave was between 886.2hpa and 912.1hpa, with an average air pressure of 906.66hpa, which was slightly higher than the air pressure outside the cave (886.2hpa-899.9hpa) Figure 2), the total body is within the normal range.

[0042] The observation data results show that, in addition to the cave entrance and the cave connecting part with underground river, the cave wind speed of most cave sections is basically zero Figure 2 . It shows that the development and utilization of cave tunnel is relatively closed, the air movement in the cave is affected by the temperature and pressure difference inside and outside the cave and the flow of underground river, and then produces weak wind speed (<1.0 m / s), but the airflow is slow, and the overall belongs to "static cave".

[0043] Positive and negative ion concentration:

[0044] The average concentration of negative oxygen ions inside and outside the development and utilization cave section is 5370 / cm 3 and 1350 / cm 3 , respectively. The farther into the cave, the greater the negative oxygen ion concentration value, and the overall value curve presents the characteristics of high in the middle and low on both sides (see Figure 2 and Figure 4 ). Among them, the highest point is located at the H-J observation point in the cave, which is 8600-14000 / cm 3 , in the high concentration area of negative ions, indicating that there are still many negative ion sources in the cave.

[0045] The average concentration of positive oxygen ions inside the cave is 4235 / cm 3 , and the average concentration of positive oxygen ions outside the cave is 1600 / cm 3 . The farther into the cave, the greater the positive oxygen ion concentration value, and the concentration change curve is similar to that of negative oxygen ions, which presents the characteristics of high in the middle and low on both sides (see Figure 2 and Figure 4 ). Among them, the high value point is located at the G-J observation point in the cave, which is 6500-7000 / cm 3 . As can be seen from Figure 2 , the high concentration area of positive ions has a small unipolar coefficient (ratio of positive and negative ion concentrations), but it does not mean that there are more air pollution sources in the cave and the air has been polluted. The smaller the unipolar coefficient, the fewer the air pollution sources in the cave, and the better the quality of the air.

[0046] The unipolar coefficient, that is, the ratio of positive and negative ion concentrations, is equal to 1 or less than 1, which can give people a comfortable feeling. The average value of the unipolar coefficient inside the development and utilization cave section is 0.90, which is less than 1 (as shown in Figure 2 ), and the average value of the unipolar coefficient at the cave entrance is 1.3. Since human activities at the cave entrance are relatively frequent than inside the cave, the air measured on the same day may be slightly affected and produce a small amount of fluctuation, but overall, the air pollution inside and outside the development and utilization cave section is relatively small, and the quality is good, which is beneficial to human health.

[0047] An assessment of air quality inside caves is established, and its calculation formula is as follows:

[0048] P CI =(n - / 1000)×(1 / q);

[0049] Among them, P CI n is an air quality assessment index. - The concentration of negative air ions is denoted by q, where q is the unipolar coefficient, i.e., the concentration of positive air ions.

[0050] The ratio of ions to negative ions;

[0051] Where q = n + / n - ;n + 1000 is the concentration of positive air ions, while 1000 is the minimum concentration of negative air ions required to meet the biological effects on the human body.

[0052] like Figure 5 As shown, air quality is classified into five levels based on the air quality assessment index;

[0053] The average Air Quality Index (CI) for the developed and utilized tunnel section was 7.73, varying between 0.77 and 28.00, with many values ​​above 10 and a maximum of 28. The average CI outside the tunnel was 1.04, exceeding the critical threshold (1.0) for the "cleanest" level in the air quality grading standard. Figure 4 As shown, the air quality assessment index increases as you go deeper into the cave, and its concentration change curve tends to be consistent with the positive and negative ion concentration change curves, showing synchronous and similar changes. Therefore, the air there belongs to the cleanest level.

[0054] The ecological carrying capacity of a karst cave refers to the number of tourists a cave can accommodate under certain spatial and temporal conditions without causing significant pollution or damage to the cave's ecological environment and while meeting environmental quality standards. It should be calculated based on the permissible CO2 concentration in the cave. In this embodiment, the upper limit of CO2 concentration for the developed and utilized cave section is 856 ppm. Considering the environmental effects of changes in the cave's air environment and the visitor experience after the cave is opened, 1000 ppm is used as the threshold (ct) for ecological environment change. Tourists exhale 25 L of CO2 per hour; if the cave is planned to be open for 8 hours daily, the average CO2 exhalation per person will be 200 L. The volume of the developed and utilized cave section is approximately 5,250,000 m³. 3 The formula for calculating its ecological carrying capacity is:

[0055]

[0056] Among them, E c To develop and utilize the daily capacity of the cave section for ecotourism, the unit is person-times; ct C0 is the maximum concentration of CO2 in the measured cave air, in ppm; is the exhalation amount of CO2 per person during the cave opening period, in L; V is the volume of the cave, in m 3 .

[0057] The ecological environment capacity evaluated by CO2 concentration is large (Ec=37800 people / day) due to the large space volume of the cave system in the development and utilization section. Given that the development and utilization section has a certain self-purification capacity, the above results are only the minimum values under ideal conditions. Therefore, after the future opening of the development and utilization section, as long as the ecological environment capacity is properly controlled, the CO2 concentration air environment quality can be maintained relatively stable.

[0058] The relatively stable and slightly higher air pressure and low wind speed in the development and utilization section of the cave compared to the external environment have a positive effect on maintaining the isothermal, isohydric, and relatively stable air environment quality in the cave. For example, the air pressure in the cave is an important indicator of the cave environment, which has an important influence on the effective development, management of tourist caves, and the health (comfort) of tourists. There is a small pressure difference and temperature difference between the air temperature and pressure inside and outside the development and utilization section of the cave, thereby attracting air flow through the surrounding rock fissures, cave passages, and underground rivers to slowly flow from high pressure and high temperature to low pressure and low temperature, thereby forming a slow air flow inside and outside the cave, forming a cave breathing effect. This air flow can bring fresh air from the outside into the interior of the cave and circulate inside the cave, thereby increasing the oxygen content inside the cave. At the same time, the surrounding good vegetation ecological environment can provide a continuous source of water vapor to the cave, allowing the cave to maintain high humidity throughout the year, which is not only beneficial to the protection and growth of stalactites, but also creates a good cave ecological environment and touring environment. The higher concentration of negative oxygen ions outside the cave may be related to the higher vegetation coverage, and the higher concentration of negative oxygen ions inside the cave is due to the fact that the cave roof and walls have a certain amount of dripping and flowing water all year round, the water molecules split by the falling water at a high altitude produce a higher concentration of negative ions, and the bottom of the cave is connected to the underground river, the cave passage is relatively closed, and the air exchange inside the cave is slow, which are important reasons for the high concentration of negative oxygen ions. According to the research on the effect of air negative ions on the human body, when the air negative ion concentration reaches 1000 / cm 3 above, it is beneficial to human health, and the air negative ion concentration at all observation points in the cave reaches 1000 / cm 3 above.

[0059] In summary, the air environment quality in most sections of the cave in this embodiment is excellent and suitable for tourism development.

[0060] Based on the above embodiments, the conclusion of the air environment development and utilization suitability evaluation of the cave in this embodiment is:

[0061] (1) The average air temperature in the tunnel section is 17.2 DEG C, which is basically the same as the average air temperature (16.9 DEG C) in Leiyang County, the average relative humidity is 94.74%, the average concentration of CO2 is 625.82ppm, which belongs to the first level of health standard, the air pressure (flow) environment in the tunnel is good, and the air flow is slow.

[0062] (2) The average concentration of negative oxygen ions in the tunnel and outside the tunnel is 5370 / cm 3 and 1350 / cm 3 , respectively, the maximum value is 14000 / cm 3 , which is much higher than the index of "1000 / cm 3 above which is beneficial to human health".

[0063] (3) The average value of the monopolar coefficient (q) in the tunnel is low, which is 0.90, the average value of the air quality evaluation index (CI) in the tunnel is 7.73, and the value in many places is more than 10, the highest value can reach 28, the average value outside the tunnel is 1.04, which is much larger than the critical index (1.0) of the "cleanest" level in the air quality classification standard, and is suitable for carrying out cave tour activities.

[0064] The above is only the preferred embodiment of the present application, which is only used to help understand the method and the core idea of the present application, and the protection scope of the present application is not limited to the above-mentioned embodiments, and any technical scheme belonging to the idea of the present application belongs to the protection scope of the present application. It should be pointed out that, for ordinary skilled persons in the technical field, some improvements and decorations without departing from the principle of the present application can also be regarded as the protection scope of the present application.

[0065] The present application solves the problem that the research on the air environment of the tourist cave in the prior art in China mainly concentrates on the cave climate environment, the tourist activities and the air self-purification capacity, and the research on the development and utilization suitability of the cave air environment is relatively less and lacks relevant standards, through setting up multiple detection devices for detecting air environment indexes inside and outside the cave, the numerical curve corresponding to the detection indexes inside the cave, the position, structure and environment inside the cave can be obtained, and through the comparison and table statistics of the detection indexes, the development and utilization suitability of the air environment inside the cave is evaluated, the evaluation result and the classification standard are obtained in combination with the relevant standards, and scientific basis and reference value are provided for protecting the air environment, ecology and tour suitability and risk inside the cave.

Claims

1. A method for evaluating the suitability of developing and utilizing a cave air environment, characterized by, The method comprises the following steps: S1, using artificial patrol or fixed-point monitoring, from the cave entrance to the exit, through the equipment set at multiple measuring points to detect the cave external and internal air environment evaluation series indexes, including air temperature, relative humidity, CO2 concentration, air positive and negative ions, air pressure and wind speed; S2, establishing the data change curve of each index at each measuring point, and determining the conditions of each index inside the cave through the curve; S3, establishing the cave air quality evaluation, and the calculation formula is: P CI = (n - / 1000) x (1 / q); where P CI is the air quality evaluation index, n - is the concentration of negative air ions, and q is the unipolarity coefficient, i.e., the ratio of positive ions to negative ions in the air. where q = n + / n - ; n + is the concentration of positive air ions, 1000 is the concentration of negative air ions that meets the minimum requirement of human biological effects; S4, according to the air quality evaluation index, the air quality is divided into five levels; S5, according to the health standard, the influence of CO2 concentration on the cave air quality is evaluated; S6, according to the allowed concentration of cave CO2, the karst cave ecological environment capacity is calculated, and the calculation formula is: wherein E c is the daily capacity of the cave section for ecotourism, in person-time; c t is the set CO2 target concentration or allowable concentration, in ppm; and c0 is the maximum concentration of CO2 in the measured cave air, in ppm. V is the volume of the cave in m3 3 .

2. The method of claim 1, wherein the method is a method of evaluating the suitability of a cave air environment for development and utilization, characterized by, The detection of CO2 concentration in the indexes is used for air quality evaluation of the CO2 concentration and spatial distribution characteristics in the cave.

3. The method of claim 1, wherein the method is a method of evaluating the suitability of a cave air environment for development and utilization, characterized by, The detection of air pressure in the indexes is used for evaluation of the oxygen content in the cave.

4. The method of claim 1, wherein, The detection of wind speed in the indexes is used for evaluation of the sealing degree of the cave.

5. The method of claim 1, wherein the method is a method for evaluating the suitability of development and utilization of a cave air environment, characterized by, The detection of air positive and negative ions in the indexes is used for evaluation of the air quality in the cave.

6. The method of claim 1, wherein, The five levels in S4 are A level, the cleanest CI>1.0; B level, general clean CI=1.0-0.7; C level, medium clean CI=0.69-0.50; D level, allowable CI=0.49-0.30; and E level, critical value CI<0.30.

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