Ozone can also irritate eyes and reduce visual sensitivity and vision. It will also destroy vitamin E in the skin, causing wrinkles and dark spots on the skin. When the ozone concentration is above 200 μ g/m3, it will damage the central nervous system, causing headache, chest pain and decreased thinking ability.
Ozone will hinder the oxygen transmission function of blood and cause tissue hypoxia; Impaired thyroid function and bone calcification. Professor Paul Wentworth of Scripps Institute of Applied Science in the United States has done research and found that ozone can destroy the immune function of human body, induce chromosome aberration of lymphocytes, destroy the activity of some enzymes and produce hemolytic reaction.
Ozone is not a welcome good thing for plants. Biologists from the University of Valencia, Spain, published a paper in 2006, suggesting that ozone can reduce the concentrations of chlorophyll, carotenoids and carbohydrates in plants, thus affecting photosynthesis and reducing crop yield.
You may be sensitive to visible pollutants such as smog and dust, but not many people know about ozone pollution. In contrast, ozone is more like an "invisible killer".
In fact, in addition to the Beijing-Tianjin-Hebei region, there have been different levels of ozone pollution in Chengdu, Jinan and Zhengzhou recently.
What is ozone?
Ozone (o? ), also known as superoxide, is oxygen (o? ) allotrope; Ozone is a trace gas in the earth's atmosphere, which is formed by the decomposition of oxygen molecules in the atmosphere into oxygen atoms by solar radiation, and then the oxygen atoms combine with the surrounding oxygen molecules, containing three oxygen atoms. More than 90% of ozone in the atmosphere exists in the upper atmosphere or stratosphere, which is 50 kilometers away from the ground 10 ~ 50. This is the atmospheric ozone layer that needs human protection.
There are still a few ozone molecules hovering near the ground, which can still block ultraviolet rays to some extent; However, some experts have found that the ozone concentration in the near-surface atmosphere is increasing rapidly, which is not good. Although ozone plays an important role in protecting human beings and the environment in the stratosphere, if its concentration increases in the troposphere, it will have harmful effects on human health.
Therefore, some experts say that ozone is a "Buddha in the sky and a demon in the ground".
How is ozone produced?
Most ozone is caused by man-made emissions.
According to reports, a small amount of ozone is transported from the stratosphere to the near ground, but most of it is formed by the secondary transformation of nitrogen oxides (nitrogen oxides) and volatile organic compounds (VOCs) emitted by human beings under high temperature lighting conditions.
The intensity of solar radiation is the main factor affecting the photochemical reaction rate of the lower atmosphere. The formation of near-surface ozone is closely related to light and temperature. The higher the temperature, the greater the solar radiation intensity and the higher the ozone concentration level. Therefore, ozone exceeding the standard mostly occurs in summer.
Nitrogen oxides mainly come from motor vehicles, power plants, coal-fired boilers and cement kilns. Volatile organic compounds mainly come from the emissions of motor vehicles and petrochemical industries and the volatilization of organic solvents. Therefore, green travel can directly reduce pollutant emissions, prevent the formation of secondary metabolites, and ultimately reduce ozone pollution.
Compared with the "roaring" smog, ozone is much more "low-key" and quietly "hidden" in the clear sky of Wan Li, but since it was included in the summer monitoring index in recent years, it has become the chief culprit of atmospheric environmental pollution in many cities.
"Low-key" ozone is more terrible than PM2.5
Compared with physical contamination, such as black and odorous water pollution, pungent yellow and black smoke pollution and smog pollution mixed with fine particles, the public and even the environmental protection departments have always taken colorless and odorless ozone pollution lightly.
How to prevent ozone weather?
Up to now, people have a * * * understanding of the positive role of ozone and what measures humans should take to protect the ozone layer, and have done a lot of work. However, although people have realized the negative effects of ozone layer, there is no really feasible way to solve these problems except atmospheric monitoring and air pollution prediction.
Compared with PM2.5, ozone pollution is more subtle. Even under clear blue sky, especially in some cloudy and windless weather, ozone pollution is most likely to occur.
Wearing a mask is useless for blocking ozone, and neither is the indoor air purifier. Some purifiers themselves also produce ozone, and improper use will cause secondary pollution. Therefore, once the ozone concentration exceeds the standard, you should try to go out, especially children, the elderly and patients with heart disease and respiratory diseases, and avoid outdoor activities.
Beijing Environmental Monitoring Center said that it will take time to completely solve the ozone problem, and there are also ways to avoid it. Ozone pollution has obvious characteristics of time law, and the over-standard period is concentrated in the afternoon to evening with high temperature and strong sunshine. Moreover, ozone is unstable and easy to decompose, and the indoor ozone level is usually lower than that outside. Therefore, according to the real-time concentration of ozone, we can reduce or avoid trips and outdoor activities from afternoon to night and carry out effective self-protection.
Therefore, in view of this weather, the best way is to reduce going out and try to stay indoors during the day.