Attention should be paid to the rebound of ozone concentration, and PM2.5 and ozone should be treated together

- Nov 20, 2020-

On October 13, the 2020 China Eco-Environment Industry Summit Forum and the second China Environmental Expo opened in Chengdu. At the forum, He Kebin, academician of the Chinese Academy of Engineering and director of the Ecological Civilization Research Center of Tsinghua University, gave a keynote speech on the topic of "New Ideas for Air Pollution Prevention and Control in the Fourteenth Five-Year Plan".On October 13, the 2020 China Eco-Environment Industry Summit Forum and the second China Environmental Expo opened in Chengdu. At the forum, He Kebin, academician of the Chinese Academy of Engineering and director of the Ecological Civilization Research Center of Tsinghua University, gave a keynote speech on the topic of "New Ideas for Air Pollution Prevention and Control in the Fourteenth Five-Year Plan".

He Kebin said that substandard ozone concentration has become the primary environmental problem in some cities and should be paid attention to. At the same time, the realization of my country’s mid- and long-term atmospheric environment governance must have "three synergy", specifically: the coordination of PM2.5 and ozone, The synergy of air quality and health effects, the synergy of atmospheric environment and climate. In He Kebin's view, the "three major synergies" will be the main trend and trend of future atmospheric environmental governance.


The problem of substandard ozone concentration in some cities has gradually emerged


He Kebin has long been engaged in research on air pollution control theory and technology, including fine particulate matter PM2.5, acid deposition, and regional composite air pollution control. In 2018, He Kebin was awarded the "2016~2017 Green China Person of the Year".


"Over the past 40 years of reform and opening up, China has gradually increased its air pollution control efforts and achieved different environmental control goals at different stages. The results have been remarkable. In the 1980s we dealt with smoke and dust, and in the 1990s we dealt with acid rain and sulfur dioxide. Pollutant emissions and the reduction of PM2.5 concentration." He Kebin said.


He Kebin pointed out that the current Chinese economy is developing steadily while pollutants are declining. This is a very gratifying situation. But now there is a new problem, which is the rebound of ozone concentration.


According to He Kebin, the six pollutants of SO2, NO2, PM10, PM2.5, CO, and O3 need to meet the standards when the air index of my country's urban air quality assessment meets the standards in order to meet the standards today. Nowadays, although PM2.5 still accounts for the majority of the days under the standard, the proportion of days with the ozone concentration under the standard is increasing. Especially in some southern cities, the problem of substandard ozone concentration has become the primary problem.


"So far, in view of the three types of typical mixed air pollution that have occurred in developed countries, China's basic situation is: first, it has basically completed the control of acid rain pollution; second, it is still continuing to complete the control of PM2.5. More and more cities are meeting the standard, but more than 45% of the cities still fail to meet the standard; the third is to curb the rising trend of ozone as soon as possible, and the coordinated control of PM2.5 and ozone should be included in the agenda during the "14th Five-Year Plan" period. "He Kebin said.


PM2.5 and ozone should be treated together


"From a principle point of view, ozone and PM2.5 have a certain degree of homology. If we do well, we can achieve double reduction in coordinated emission reduction." He Kebin said. In his view, the core issue of the coordinated management of PM2.5 and ozone is the coordinated emission reduction of VOC and nitrogen oxides.


He Kebin said that the current decline in my country's PM2.5 is mainly due to a sharp drop in sulfur and "primary PM2.5", but the annual emissions of nitrogen oxides and VOCs (volatile organic compounds) are still above 20 million tons. Nitrogen oxides and VOCs will produce ozone through a chemical reaction at a certain ratio. If the ratio of nitrogen oxides and VOCs is not suitable, the ozone concentration will increase. Therefore, the coordinated reduction of nitrogen oxides and VOCs can achieve PM2. 5 Synergistic governance with ozone.


At present, some cities have implemented coordinated governance in accordance with this method and achieved good results. According to He Kebin, Beijing has coordinated the reduction of nitrogen oxides and VOCs in a certain proportion from 2010 to 2019. PM2.5 has dropped significantly while ozone has not risen. At the same time, Chengdu has also done a good job in this area, achieving both PM2.5 and ozone reduction.


It should be pointed out that the above-mentioned collaborative governance methods have certain difficulties. Especially for the reduction of VOCs, there are still many difficulties in technology and supervision. This field may be an increase in the future environmental equipment and monitoring and supervision market.


In He Kebin's view, in addition to the coordinated management of PM2.5 and ozone, the synergy of air quality and health effects, and the synergy of atmospheric environment and climate cannot be ignored.


"At the end of the 13th Five-Year Plan, my country may achieve that 60% of the urban air quality meets the qualified standard, and this proportion will rise to 75% in the 14th Five-Year Plan." He Kebin said that air quality standards are closely related to human health. In order to protect human health, it may force the formulation of air quality standards, thereby promoting further improvement of air quality.


He Kebin believes that by the end of the "14th Five-Year Plan", my country's current ("Ambient Air Quality") 2012 standard will be used for 13 years, and nearly 80% of the cities will meet the standard. The air quality standard is required for human health. It is bound to take another step.


"To achieve such air quality standards, it is necessary to coordinate the management of atmospheric environment and climate issues and solve the problem of carbon reduction." He Kebin said that low-carbon requires the transformation of the energy structure, and the proportion of fossil energy such as coal and natural gas is reduced. The proportion of fossil new energy sources has increased substantially. Combining with carbon reduction will greatly increase the emission reduction of other types of pollutants, and pollutants such as sulfur dioxide and PM2.5 will be reduced by 70% to 90%. Under the above-mentioned circumstances, China will realize the reduction of major pollutants from the ten-million-ton level to the one-million-ton level, which will enable more regions to reach higher air quality standards.


"To do the three major synergies and combine blue sky with low carbon is one step closer to the goal of building a beautiful China. I look forward to this very much!" He Kebin said.