[Perspective Club · Ecological Supervision] Why did the nation's ozone pollution rebound in the first half of the year?Official authority analysis comes

The Ministry of Ecology and Environment has recently notified the national ecological environmental quality status in the first half of this year. Data show that from January to June, the national environmental air quality has generally improved. The concentration of 6 major pollutants in 339 prefecture -level and above cities is "five drops and one liter". The concentration of PM2.5 (fine particles) decreased by 5.9%year -on -year, while the concentration of ozone (O₃) increased by 4.3%year -on -year.

The concentration of 6 major pollutants in 339 prefecture -level and above cities nationwide "five drops and one liter"

The average concentration of fine particles (PM2.5) is 32 micrograms/cubic meter, a year -on -year decrease of 5.9%;

The average concentration of inhalation particulate matter (PM10) is 55 micrograms/cubic meter, a year -on -year decrease of 8.3%;

The average concentration of sulfur dioxide (SO2) is 9 micrograms/cubic meter, a decrease of 10.0%year -on -year;

The average concentration of nitric oxide (NO2) was 21 micrograms/cubic meter, a year -on -year decrease of 12.5%;

The average concentration of carbon monoxide (CO) was 1.1 mg/cubic meter, a year -on -year decrease of 8.3%;

The average concentration of ozone (O3) was 144 micrograms/cubic meters, an increase of 4.3%year -on -year.

From January to June this year, the concentration and year -on -year changes of 6 indicators and year -on -year changes in 339 prefecture -level and above cities in the country showed the characteristics of "five drops and one liter". Picture source: China Environmental Monitoring Network

The national ozone concentration has rebounded. What are the reasons? At the recent routine press conference held by the Ministry of Ecology and Environment, Liu Youbin, spokesman for the Ministry of Ecology and Environment, gave an authoritative answer to this.

Photo source: Photo Conferry at the Ministry of Ecology and Environment

There are two main reasons for the ozone concentration to rebound.

At the press conference, Liu Youbin, a spokesman for the Ministry of Ecology and Environment, said that the secondary standard limit for the ozone in the "Environmental Air Quality Standard" in my country is 160 micrograms/cubic meter, which is consistent with the standards of WHO. From the past 5 years, my country's ozone concentration has maintained a relatively stable state. From the first half of 2018 to 2022, the national ozone concentrations were 143, 143, 141, 138, 144, 144 micrograms/cubic meters, respectively. Although there were slight fluctuations in the age, the overall stability was about 140 micrograms/cubic meter.

"In the first half of this year, the national ozone concentration rebounded, mainly in the following two reasons." Liu Youbin said that one is that the anterior body discharge of ozone pollution is still high. Studies have shown that among the four major atmospheric pollutants in China, sulfur dioxide and PM2.5 emissions have dropped to one million tons, while ozone pollution is still tens of millions of tons.

Science reading

Nitrogen oxides and volatile organic matter (VOCS, NOX) are common pre -bodies that generate PM2.5 and ozone. Under the ultraviolet rays in the strong sunlight, they produce ozone through photochemical reactions. The generation of ozone increases the oxidation properties and will also accelerate the generation of secondary particulate matter.

During the year, ozone concentrations generally increased from May, reached the highest point in July and August, and gradually decreased after entering autumn. Especially in the summer and autumn afternoon of the strong sunlight from June to September, it is usually 1 pm to 4 pm. When the temperature is high and the relative humidity is low, ozone is more likely to exceed the standard.

The second is that the meteorological conditions are generally unfavorable. From April to June this year, Beijing -Tianjin -Hebei, surrounding areas, Yangtze River Delta regions, Fenwei Plain and other key areas such as increased temperatures, decreased precipitation, and reduced humidity, and meteorological conditions were nearly 5 years of worst levels, which led to the oxygen concentration in the three major regions. The year -on -year rising significantly led to the rebound of ozone pollution across the country.

Summer assistance and rectification problems, continue to promote VOCS and NOX collaborative emission reduction

Since May, the Ministry of Ecology and Environment officially launched the air quality of key areas to improve summer supervision and assistance work. Focusing on the junction of Beijing -Tianjin -Hebei and surrounding areas, Fenwei Plain, Jiangsu, Wanjun, and Yuyu, focusing on key industries, focusing on solving ozone to ozone ozone Outstanding issues of pollution.

According to Liu Youbin, this summer supervision and assistance comprehensively considers the situation of the epidemic prevention and control situation and the requirements of stabilizing the economic market, and develops in the form of online supervision and assistance. List, guide the locality to conduct on -site investigation. As of July 20, there were more than 5,000 clues to 89 cities. Ecological and environmental departments at all levels have conducted in -depth on -site investigation, rectified a number of outstanding environmental problems, and promoted volatile organic matter and nitrogen oxidation to reduce emission reduction.

"In the next step, the Ministry of Ecology and Environment will quickly promote the introduction of the" Action Plan for the Comprehensive Improvement of Air Quality ", and continue to strengthen PM2.5 pollution prevention and control, and in -depth comprehensive treatment and source replacement of volatile organic objects to promote volatile organic matter and nitrogen oxides ( VOCS, NOX) coordinated emission reduction, effectively curbing the growth trend of ozone concentration. By 2025, the total discharge of volatile organic matter and nitrogen oxide will decrease by more than 10%compared with 2020, and the coordinated control of PM2.5 and ozone will be achieved to comprehensively improve the environment. Air quality. "Liu Youbin said.

Extended reading

Ozone (O₃) is a pale blue gas, which has strong oxidation, and it is difficult for ordinary people to detect ozone pollution.

The high -concentration of ozone in the ground can stimulate and damage the mucosa tissue such as the eyes and respiratory systems, which has a negative impact on human health. Studies have shown that every cubic meter of ozone content in the air increases 100 micrograms, human respiratory function will weaken by 3%. When ozone reaches a certain concentration, it can make people breathe accelerate and chest tightness. If the concentration is further improved, the pulse acceleration, tiredness, and headache can be caused. Ozone pollution can also cause damage to the environment. For example, it can cause necrosis, falling off, harm the ecological environment, and reduce production of crops. Where does the ozone near the ground come from? Experts said that the volatile organic matter and nitrogen oxides (VOCs, NOX) of petrochemical industry, gas stations, and automotive exhaust gas (VOCS, NOX) will occur in the condition of sunlight. Ozone -based photochemical smoke. At the same time, the generation of ozone increases the oxidation of large gas and accelerates the generation of secondary particles.

Ozone pollution prevention is a long -term process. How should we better prevent ozone pollution hazards? Experts point out that ozone is mainly based on gaseous, and wearing masks basically cannot effectively protect. The best way is to avoid contact. When the afternoon is strong in the afternoon, stay away from the roadside and the severity of the decoration pollution. Children, elderly people and other sensitive people should try not to go out when the sun is strong.

We must not only pay attention to health protection, but also actively participate in ozone pollution prevention. For example, priority to choose products or services with less volatile organic discharge, buy water -based paint, and choose gas stations with normal oil and gas recycling facilities when refueling to refuel the car, which can provide strong support for ozone pollution prevention.

(Reported by the Perspective Club Comprehensive China Environment Network, the official website of the Ministry of Ecological Environment, China Environmental Monitoring Network, People's Daily)

Edit: Cheng Yi

School pair: Wu Yueran

Review: Gong Zimo

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