Recently, there is news about ozone over the blue sky and white clouds, which has caused many people to hate ozone. 9.16 is the international ozone layer protection day, reporters asked the experts to clear up doubts: ozone, what is bad is good? Should we do our best to cut ozone or should we do our best to protect it?
Low altitude ozone is different from high altitude ozone
"First of all, we have to clarify the concept that ozone in the upper stratosphere is different from ozone near the surface of the stratosphere." Nanjing University of Information Science and Technology, Ph.D., atmospheric science and environmental meteorology national experimental teaching center director Professor Zhu Bin told reporters that the two not only causes is not the same, more importantly, from the functional perspective, it can be said is an angel, a devil.
From the origin, from the ground 20 - 50 kilometers in the stratosphere, ultraviolet radiation interrupted oxygen molecule (O2) chemical bond between the two oxygen atoms, one oxygen atom remaining (0) and another (02) with molecular oxygen, will form the ozone (03); ozone in the ground that is the two pollutants produced by human activity through a series of complicated photochemical reactions caused by. High temperature combustion of factories, vehicles and so on will produce nitrogen oxides and VOC (volatile organic compounds), and the latter will produce ozone pollution under the irradiation of intense sunlight."
The high altitude ozone meter is about 33 tons, but has a very small proportion of the entire atmosphere. If it is tiled on the surface, the thickness is only 3 millimeters - only one gram of the earth's height. But the thin layer of ozone absorbs most of the sun's ultraviolet rays that are damaging to life, creating a natural protective effect on life on the planet. "It is no exaggeration to say that all life on earth, like water and oxygen, can not be separated from the ozone layer of the atmosphere. Atmospheric ozone is an umbrella for all living beings on the earth.". If ozone levels in the stratosphere are greatly reduced, people will suffer from skin cancer and even death."
And low altitude ozone is a more difficult to control than PM2.5 pollutants, once exceeded, the environment and human health hazards are great.
High altitude ozone thinning, near surface ozone often exceeds standard
Scientific research found that, along with the human activities, especially chlorofluorocarbons (CFCs) and halons (halons) artificial chemicals are widely used, these substances can easily damage the ozone layer, so that a significant decrease in the total ozone altitude.
In the meantime, two major events related to it have had a great impact on the whole world. One is Holland, Mexico and the United States three scientists study results confirmed the destruction of artificial substances on the ozone layer, the results of the 1995 Nobel prize for chemistry; two scientists found in Antarctica, about about 20000000 square kilometers in area for ozone depletion region, the ozone 14-19 kilometers above reduce reached more than 50%. The scientists vividly called "ozone hole".
In recent years, international organizations have worked together to reduce the use of destructive compounds. According to Hua Fenglin, director of the Jiangsu environmental economic and technical cooperation center, the Vienna Convention on the protection of the ozone layer was adopted at the "protection of the ozone layer conference" held in Vienna in 1985. Since then, the international community has signed the "Montreal Protocol", the provisions of the production and use of CFCs to control the schedule 5 and 3 kinds of Halon substances, then made several adjustments and amendments, "the objective is to minimize the destruction of the ozone layer". The Chinese government joined the Convention in 1989, signed the protocol in 1991, and carried out the work in full compliance.
At the same time, near the ground ozone concentration exceeding standard problem, but gradually improved in the PM2.5 at the same time, increasingly prominent. Reporters noted that in the past two years, in Beijing, Tianjin, the Yangtze River Delta, the Pearl River Delta region, every spring and summer, ozone is often the primary pollutant in urban air. According to the data provided by environmental protection agencies, only 4-8 months of this year, Nanjing has 37 days due to ozone pollution caused by non-compliance".
What can we do to protect ozone from bad ozone?
First, the production and use of ODS (ozone depleting substances) are eliminated and eliminated. In 2007, freon (CFC), which was widely used in air conditioners and refrigerators, was completely replaced in our country. In 2015, methyl bromide widely used in grain storage was completely prohibited...... Our province has participated in the ODS reduction demonstration project since 2007. Hua Fenglin said, Jiangsu is the country's important ODS (ozone depleting substances) production, use and sale of provinces, therefore, in promoting the elimination of these substances on the replacement, the relevant enterprises have many articles to do.
To protect the ozone layer, in the final analysis, is to protect ourselves. For the public, how to reduce the consumption of ozone layer in daily life? The environmental protection department suggested that in life, choose a refrigerator air conditioning, mousse, air freshener, fire extinguishing agent, spray insecticide, bleach and other consumer products to pay attention to ingredients. In addition, the "buy a refrigerator, we must look at environmental protection sign; treatment of waste household appliances, don't forget to remove the refrigerant; automotive air conditioning refrigeration, going with the refrigerant recycling equipment repairs".
And to reduce the "bad" ozone, reduce motor vehicle use and reduce coal burning is a big direction. "However, cut surface ozone, which is a very complex process, because the atmospheric chemical reaction has a nonlinear effect, sometimes VOC is reduced, but the ozone up, so the current in the world in terms of reducing ozone concentration is more difficult than cutting the PM2.5 problem." Zhu Bin says.