Study On The Characteristics Of Spatio-Temporal Distribution Of Nagative (Oxygen) Ions In The Air Elements Variety In Karst Cave And Its Impact On The Cave Environment

With the continuous development of urbanization,PM2.5 and other air pollution problems seriously threaten the quality of life and health of human beings.Air anion has the effect of sterilization,dust reduction and clean air.Where the negative ion concentration is high,it can effectively adsorb air particles such as PM2.5,which also gives birth to the development of health tourism,in addition to the forest convalescent industry.The development of cave recuperation tourism can not be separated from negative ions.By studying the temporal and spatial distribution characteristics and influencing factors of negative ions in caves,it can provide certain theoretical basis and decision-making guidance for the development of cave tourism resources.Four representative caves in Hongguoshu Scenic spot,Suiyang County,Guizhou Province,were selected as the research objects.On the basis of understanding the structure of the caverns,monitoring points were set up to monitor the air and meteorological changes outside the caverns.With the help of GIS,The spatial and temporal distribution pattern of negative ion concentration in the cave is analyzed,and the interaction between the environmental index inside and outside the hole and the negative ion concentration is discussed.the main conclusions are as follows:?1?In terms of seasonal variation,except for the point near the mouth of the cave,each monitoring point shows the seasonal variation characteristics of high summer and low winter,in which the negative ion concentration in the water curtain cave is affected by the Lenard effect,and the seasonal characteristics of the negative ion concentration in the cave are significantly weak.The range of change is the largest;The variation of negative ions at each monitoring point in Tianxing cave and Tianmen cave is obvious.It is the high value of negative ion concentration from July to September and the low value from October to February of the following year.The maximum variation range is about 800 Ions/cm³ and 13000 Ions/cm³.In terms of diurnal variation,the diurnal variation characteristics of different seasons are different,from 8:00 in spring to 11:00in the morning that is the high value of negative ions concentration in diurnal variation,and the negative ion concentration in the hole decreases gradually after 11:00,and the lowest value appears after 16:00;In summer,it increases gradually in the morning,reaches the maximum value between 11:00 and13:00 at noon,and decreases at all points in the afternoon,and increases and reaches the maximum between 10:00 and 12:00 in autumn.The lowest negative ion concentration appeared at 8:00 and 9:00,but the diurnal variation was not significant in winter.In terms of spatial variation,the concentration of negative ions in the four caves is larger than that outside the cave,and on the whole,from the mouth to the hole,the concentration of negative ions in the four caves is higher than that outside the cave.The concentration of negative ions increases gradually from the transition section of the cave to the depth of the cave.The existence of water plays a decisive role in the distribution of high concentrations of negative ions in the cave.Except for the star cave,the concentration of negative ions near the water body is higher than that in other areas.The concentration of negative ions produced by static water is lower than that at the dynamic flow,and is affected by the adhesion of negative ions to some heavy particle molecules.In some narrow and low tunnels,the concentration of negative ions is twice as high as that in other adjacent regions.?2?There was a positive correlation between negative ion concentration and CO₂ concentration as a whole,that is,the higher the negative ion concentration was,the higher the CO₂ concentration was,but the water curtain hole was not significant.There was no significant positive correlation between negative ion concentration and air temperature in the cave,and the correlation between negative ion concentration and air temperature was higher in summer and autumn,but lower in autumn and winter.There was a significant positive correlation between humidity and negative ions in summer and winter,but not in spring and autumn seasons.due to the existence of a large number of skylights in the star cave,the relationship between negative ions and relative humidity was not significant.There was a significant positive correlation between negative ion concentration and air pressure in spring and summer.In winter,air pressure had little effect on negative ion concentration.Ventilation effect It will have a strong inhibitory effect,mainly changing the background value of negative ions in the hole.The variation trend of radon radioactive concentration is the same as that of negative ions,which may be one of the main sources of negative ions in caves.The temperature and precipitation outside the cave have a significant effect on the negative ion concentration in the cave.The greater the rainfall intensity,the greater the negative ion concentration.At the same time,due to the existence of temperature difference inside and outside the hole,the seasonal variation of the negative ion concentration inside and outside the hole is caused.?3?The mean negative ion concentration in the four caves was1086-10781 Ions/cm³,all of which were above grade 3,which was beneficial to the health of tourists.The best sensory grade and comfort in the four caves were concentrated in spring and summer,especially at 8:00 in the morning and 10:00 in the morning,and the average negative ion concentration reached the highest,and the receptive grade was more suitable.The concentration of negative ions is at and above the level of benefit to body function and immune system,so it is suitable for cave recuperation.In winter,because of the weak function of keeping warm and the poor feeling grade of tourists,it is not suitable to carry out cave recuperation activities.