Cause analysis of air quality

Causes: poor diffusion conditions, external pollution, dust on the construction site.

The main reason for the decline in the ranking is that March-May is the worst season for air diffusion in Yunnan Province, and the air quality in Kunming is relatively poor under the joint influence of internal pollution discharge and external pollution transportation. The rankings in these months are not ideal, which also leads to the poor ranking of Kunming in the first half of the year.

Judging from the situation in 20 19, Kunming ranked 88th among 68 cities in China in April, which was the worst ranking since the introduction of the urban air quality ranking. According to the analysis of the relevant person in charge of Kunming Ecological Environment Bureau, in the first half of 20 19, due to the change of atmospheric circulation, the most serious weather with little rain and high temperature appeared in Yunnan in spring. According to the statistics of meteorological department, the rainfall decreased by 50% compared with the same period of last year, and the temperature rose by 2℃. The rainy season in Kunming has been delayed by nearly 20 days compared with last year. Due to the drought and lack of rain, the evaporation is very large, the air humidity in various places drops sharply, and the solar radiation is further enhanced, which leads to the obvious increase of ozone in the whole region, and the ozone in most cities obviously exceeds the standard. Compared with last year, the air quality in Yunnan Province has declined.

In addition, regional long-distance pollution transportation is the direct reason for the decline in ranking. For example, in the surrounding areas, forest fire prevention plans were burned and spring seeds were burned. In February and March this year, two serious air quality abnormal events caused by external pollution occurred. Yang Jian introduced that in fact, from March to May every year, Southeast Asian countries, provinces and parts of Kunming have spring planting and burning. However, due to wind direction, wind speed, rainfall and other factors, the annual impact degree is different and the time is different.

In addition to external pollution, Kunming is currently in a period of rapid urban development and construction, with many construction sites and a wide range. According to preliminary statistics, there were more than 700 construction sites in Kunming in 20 19, plus more than 2,000 other sites, demolition sites and exposed land. Although a lot of measures have been taken to control pollution, due to the large quantity, the total amount of pollutants such as dust is still large, and some construction units have a weak awareness of environmental protection. As long as the inspection is not carried out, the prevention and control work and management work will not be in place, especially at night. The impact of these constructions will disappear after the completion of the project, which is a short-term pollution source.

"In the next step, we will carry out further work in combination with dust control and air pollution prevention and control, and strengthen the management of pollution such as enterprises, construction sites, muck trucks and automobile exhaust. At the same time, we have also established corresponding early warning mechanisms and corresponding measures, and will take corresponding measures according to changes in air quality to continuously improve air quality. " The relevant person in charge of the Municipal Bureau of Ecology and Environment said.