Midsummer has arrived, and it’s the time of year when people have the most intensive outdoor activities. How is the air quality in various places? Ministry of Ecology and Environment: Moderate ozone pollution will occur in many places in the first half of July. The Ministry of Ec

Midsummer has arrived, and it is the time of year when people have the most intensive outdoor activities. How is the air quality in various places?

Ministry of Ecology and Environment : In the first half of July, ozone moderate pollution will occur in many places.

The Ministry of Ecology and Environment recently released the results of the national air quality forecast consultation for the first half of July. It shows that in the first half of July this year, As of July 15, most of my country has good diffusion conditions, and the air quality is mainly good to lightly polluted. However, affected by rising temperatures, moderate ozone pollution processes may occur in local areas in North China, central and northern East China, Chengdu Plain, local areas in the Sichuan Basin, and the Guanzhong area of ​​Shaanxi Province.

Ozone - "Earth's protective umbrella" or "invisible destroyer"?

In addition to particulate pollutants such as PM2.5, ozone is also an important indicator for evaluating air quality. So what exactly is ozone pollution ? What's the harm?

Ozone is an allotrope of oxygen . It is colorless at normal temperature and pressure and odorless at low concentrations. There is a layer of ozone at a height of 20 to 50 kilometers from the earth's surface, which can absorb most of the ultraviolet rays in the sun and protect life on the earth from harm. But close to the ground, ozone has a different look. When the maximum 8-hour average value of ozone concentration exceeds 160 micrograms per cubic meter, ozone pollution is formed.

The high concentration of ozone near the ground is one of the pollutions that everyone is currently concerned about. It is harmful to the human body. It is not only a health killer, but also causes the loss of crops.

How is ozone pollution formed?

The Ministry of Ecology and Environment reported that from January to May this year, the average ozone concentration in 339 cities at the prefecture level and above across the country was 138 micrograms/cubic meter, a year-on-year increase of 8.7%. How is ozone pollution formed?

Ozone is not directly emitted from pollution sources, but is the product of photochemical reactions between volatile organic compounds (VOCs) and nitrogen oxides (NOx) under sunlight. It is a typical secondary pollutant.

Nitrogen oxides and volatile organic compounds are the two "raw materials" that produce ozone. The sources of volatile organic compounds include both natural sources, mainly plant volatilization, and man-made sources caused by various human activities, such as emissions from industrial processes such as petrochemicals and industrial painting; emissions from motor vehicle exhaust and oil evaporation; decoration, Emissions from daily activities such as cooking and dry cleaning. Nitrogen oxide emissions mainly come from emissions during the combustion process of various fuels, including thermal power generation, industrial boilers and kilns, motor vehicle use, etc.

Which places and when are ozone pollution most likely to occur in my country?

The spatial and temporal distribution of ozone pollution in my country is uneven. In terms of spatial distribution, about 80% of the cities with excessive ozone concentrations are distributed in the Beijing-Tianjin-Hebei and surrounding areas, Yangtze River Delta and Fenwei Plain. They basically overlap with the distribution of cities with heavy PM2.5 pollution. The Pearl River Delta, Chengdu, The ozone concentration in Chongqing and urban agglomerations in the middle reaches of the Yangtze River is also relatively high.

In terms of time, 5 to September are the months when ozone pollution is relatively concentrated in most cities in our country, which is mainly related to sufficient sunshine, strong radiation, and high daytime temperatures during this period.

What harm can ozone pollution easily cause to the body? How to protect?

The current hot summer is the time of year when ozone pollution is the most serious. What everyone is most concerned about is, what harm will ozone pollution bring to human health? How should we take protective measures?

Experts said that if the ozone concentration in the air near the ground is too high, it can easily cause inflammatory lesions of the upper respiratory tract, causing symptoms such as coughs and headaches, and can also cause irritation to the skin, eyes, nasal mucosa. Ozone can destroy the barrier function of the skin, cause skin diseases, and cause dark spots. Three groups of people are particularly sensitive to ozone:

Children are the group with the highest risk of ozone exposure. Children often spend time outdoors and engage in more strenuous activities most of the time, so children are more likely to suffer from asthma or other respiratory diseases. Asthma is the most common chronic disease in children. Exposure to ozone may aggravate asthma.

For adults who are active outdoors, physical activity will cause people to breathe faster and deeper. During the activity, ozone will penetrate deep into the lungs and easily cause damage.

People with respiratory illnesses. Because people with these conditions often feel the effects of low concentrations of ozone earlier than people who are less sensitive.

For personal protection, try to take the following measures:

1. Ozone generally appears at noon and reaches its peak at two or three o'clock in the afternoon. During this period, it is best to reduce going out and outdoor activities, and reduce the number of indoor ventilations.

2. If you have to go out, sensitive people need to take protective measures and wear protective products such as hats, glasses, and masks.

3. Strengthen physical exercise, improve physical fitness, enhance your own immunity, and appropriately reduce the damage caused by ozone to the human body.

What "big tricks" are used by various places to accurately control ozone pollution?

With the effective control of PM2.5 and others, ozone has now become the primary pollutant affecting my country's air quality in summer. Relevant departments are also paying more and more attention to the control of ozone pollution. Let’s take a look at what “big moves” have been used in various places?

In the past few days, at the gas station in Xinghualing District, Taiyuan City, there is an endless stream of vehicles queuing up to refuel at night. Compared with before, the number of vehicles refueling has increased by 20%. Gas station staff from time to time promote the off-peak refueling policy to customers who come to refuel. So why are these measures being introduced? For the majority of car owners, choosing to refuel at night can reduce oil and gas pollution emissions in high-temperature environments during the day and alleviate the worsening of ozone pollution. Taiyuan City also clearly requires that all oil product storage, transportation and sales units must implement peak-shifting operations when loading and unloading oil products, and oil product loading and unloading operations will stop from 10 am to 6 pm every day in sunny weather.

Controlling volatile organic compounds is one of the effective ways to control ozone pollution. Measures have been introduced across the country: Xi'an will implement ozone pollution control for the city's automobile maintenance enterprises and transportation areas from June 1 to September 30. If polluted weather is predicted, emergency control measures will be initiated. Guangdong Dongguan vigorously promotes the use of new energy vehicles. 100% of new taxis, online ride-hailing, and urban logistics distribution vehicles use new energy vehicles, and more than 80% of light sanitation vehicles use new energy vehicles. At present, Beijing has taken the lead in establishing a volatile organic compound monitoring system that combines point, line and area in the country, using technical means such as manual monitoring, automatic monitoring, and navigation monitoring to provide accurate information for the collaborative management of PM2.5 and ozone pollution. Technical Support.

Ministry of Ecology and Environment: Increase structural adjustment and implement emission reduction projects to prevent and control ozone pollution

At the same time, the Ministry of Ecology and Environment also clearly stated that the focus of my country's air pollution prevention and control during the "14th Five-Year Plan" period is the coordinated control of fine particulate matter and ozone. The reduction of emissions of volatile organic compounds and nitrogen oxides will be comprehensively promoted through structural adjustments in industry, energy, transportation and other sectors, as well as the implementation of emission reduction projects.

Source: CCTV "News" Channel, China Environment APP