Can absorb more solar energy, a lot of artificial heat into the air; On the other hand, because of the dense buildings, it is not conducive to heat diffusion, forming a high temperature center, which gradually decreases to the periphery.
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Due to the high temperature near the ground in the central area of the heat island, the atmosphere moves upward, forming a pressure difference with the periphery, and the periphery converges to the central area, thus forming a low-pressure vortex in the central area of the city. In this way, it is bound to cause air pollutants such as sulfur oxides, nitrogen oxides, carbon oxides and hydrocarbons formed by burning fossil fuels in people's lives, industrial production and vehicle operation to gather in the central area of the heat island, endangering people's health and even life. Show in:
On the one hand, a large number of pollutants gather in the center of the heat island, and the concentration increases sharply, which directly stimulates human respiratory mucosa and causes cough and runny nose. In severe cases, respiratory diseases occur, especially in middle-aged and elderly people with chronic bronchitis, emphysema and asthma, with high mortality. For example, in London, England, more than 4,000 people died for this reason.
On the other hand, air pollutants can also irritate the skin, leading to dermatitis and even skin cancer. Some substances, such as chromium, will irritate the conjunctiva, cause inflammation and even lead to blindness if they enter the eyes. High levels of mercury can damage people's kidneys and cause severe abdominal pain and vomiting. Chronic mercury poisoning can also damage people's nervous system. Thirdly, people who live in the central area of the heat island for a long time will show emotional irritability, listlessness, depression, memory loss, insomnia, loss of appetite, indigestion, aggravation of ulcers, recurrence of gastrointestinal diseases and so on. This will bring untold troubles to the work and life of city people. In China, many big cities known as "stove cities", such as Nanjing, Wuhan, Chongqing, etc., have all experienced the above phenomenon to varying degrees in their development. Therefore, the urban heat island effect has become a problem that should be correctly faced and urgently solved in urban development.