What effect does dry weather have on people's health?

Too much or too little air humidity is not good for human health. When the humidity is too high, the amount of pineal hormone secreted by the pineal gland in the human body is also large, so that the concentration of thyroxine and adrenaline in the body is relatively reduced, and cells will be "lazy", and people will feel listless and depressed. Working and living in places with high humidity for a long time (such as mountains and islands) is also prone to rheumatism, rheumatoid arthritis and other damp arthralgia. However, if the humidity is too small, evaporation will be accelerated, and dry air will easily take away the moisture of human body, which will cause chapped skin, irritation of oral cavity and nasal mucosa, and symptoms such as thirst, dry cough, hoarseness and sore throat will easily induce pharyngitis, tracheitis and pneumonia. Modern medicine has also confirmed that the air is too dry or humid, which is conducive to the reproduction and spread of some bacteria and germs. Scientists have determined that when the air humidity is higher than 65% or lower than 38%, bacteria reproduce fastest; When the relative humidity is 45%-55%, the bacterial mortality rate is high. Generally speaking, the most comfortable air relative humidity for human body is 40% ~ 60%, and it will be uncomfortable if it is too high or too low. Due to the low water vapor content in the air in autumn, its relative humidity decreases, especially when the relative humidity of the air is lower than 30%, people will feel dry and rough skin, dry nose and pain, dry mouth and pharynx, dry stool, etc., and need to take preventive measures in time to avoid developing into diseases.