1. How much do you know about the harm of ozone pollution?
Although ozone comes and goes without a trace, its harm to human health cannot be ignored. The following table shows the symptoms of human body under different ozone concentrations:
Ozone pollution not only harms human health, but also causes serious economic losses. For example, ozone can cause plant leaves to die, fall off, grow bleached spots, inhibit growth, and thus reduce crop production. Studies have shown that when the ozone concentration reaches 50ppb, the national winter wheat output will be reduced by 410.32 million tons, which is equivalent to reducing the annual output of Beijing+Shanxi Province; Soybean production has decreased by 885,000 tons, which is equivalent to reducing the annual output of Jilin Province-and this is only reduced by 50ppb. With the increase of ozone concentration, the decrease will be more serious.
At the same time, ozone will cause material fading, photo fading, tire aging and so on. The material loss caused by ozone pollution in Britain is as high as1.74-345 billion pounds every year.
2. "Guardian of the Earth" or "Healthy Black Boy"?
At an altitude of 10-50km from the ground, ozone can absorb ultraviolet rays, thus protecting the living things on the earth from being killed by strong ultraviolet rays. When the ozone in the upper air decreases, the number of skin cancer patients in the world increases obviously, and the function of human immune system decreases. Studies have shown that every reduction of ozone in the upper air 1% will increase the number of blindness caused by cataracts worldwide 10000- 15000. Therefore, the ozone in the upper ozone layer is indeed a well-deserved "guardian of the earth". But once ozone reaches the surface layer about 10- 100 meters above the ground, it becomes a terrible face and becomes a "health killer". So there is a saying that ozone is more appropriate-Buddha in the sky and demon on the ground.
Where does outdoor ozone pollution come from?
The ozone polluted near the ground comes partly from the inflow of ozone layer in the upper air and partly from soil, lightning and biological discharge. These can be classified as "natural sources" and exist in nature.
The main force that causes ozone pollution is "man-made source", which mainly includes: one-off pollutants such as coal burning, automobile exhaust and nitrogen oxides (nitrogen oxides) emitted by petrochemical industry, which will generate nitrogen oxides such as ozone under ultraviolet irradiation, which is called "secondary photochemical reaction".
The research shows that only 23% of ozone pollution in the near-surface layer comes from the ozone transport of nature itself, up to 48% comes from the photochemical reaction of pollutants such as nitrogen oxides, and the rest comes from long-distance transport outside the region. It can be said that the ozone concentration in urban areas mainly depends on the emission of motor vehicle exhaust.
Therefore, to control ozone pollution, from the root, it is necessary to reduce the emission of nitrogen oxides, which is very similar to controlling PM2.5. In the final analysis, it is necessary to control emissions!
4. What is the biggest source of indoor ozone pollution?
The biggest source of indoor ozone pollution may be unimaginable, and the answer is the copier. The working principle of the copier is voltage discharge, which charges the toner cartridge, then forms a latent image through illumination, and finally completes copying ... Of course, it is difficult to understand, but it doesn't matter. The key point is that the high-pressure mercury lamp and sparks inside will emit a lot of ultraviolet rays, decompose oxygen in the air, form ozone, and harm human health. So, if there is a copier in the office, you'd better stay away from it-distance produces health! If there is a special copy room, it is best to keep ventilation and install an exhaust fan, which can dilute the ozone accumulated in the enclosed space.
5. What is the effect of ozone sterilizer?
An ordinary ozone sterilizer can kill more than 99% indoor bacterial propagules in a room of 30 square meters for 5 minutes. However, ozone with a concentration of about 1090- 1950 μ g/m3 will also be produced.
As long as it is turned off, ozone will start to decompose rapidly, and it will gradually return to a safe range after half an hour. Therefore, when using the ozone sterilizer, be sure that no one is present; Second, after disinfection and shutdown for at least half an hour, ensure that the indoor ozone concentration drops to a safe value, and then go back to the room.
Ozone is very harmful to human health. Outdoor activities should be reduced when ozone pollution occurs outdoors. At the same time, beware of indoor ozone pollution released by photocopiers and ozone sterilizers!
(Source: China Meteorological Bureau, expert: lasg Li Ting, original article, please do not reprint without authorization)
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