Why is the air in Hainan Island polluted?

101On October 28th, many Sanya citizens went outdoors and felt the fresh air brought by the blue sky and white clouds. According to the statistics of national key cities air quality daily published by the Ministry of Environmental Protection, Sanya's API index is 64, which is in good condition. Our reporter Wei Wu correspondent Christina photo

Nanhai Net Haikou 65438+1 October 29 news (Nanhai Net reporter Fu) During the period from June 65438+1October124 this year, Haikou, a city with long-term excellent air quality, experienced "light pollution", and the air quality in Sanya, Wanning, Qionghai and Chengmai in Hainan also appeared "light pollution" simultaneously. Why is there "light pollution" in Hainan, which has always made a fuss about excellent air? 101On October 28th, Yue Ping, president of Hainan Academy of Environmental Sciences, said in an interview with Nanhai. It is considered that the migration of foreign pollutants is the main reason, and the "inversion" phenomenon of local climate intensifies pollution, while the problem of local pollution sources should be paid attention to and must be controlled.

The migration of foreign pollutants is the main reason.

Yue Ping introduced that during this year's 10 period, the air quality changes in many cities and counties in Hainan, including Haikou, attracted their attention, and Hainan Academy of Environmental Sciences also organized experts to analyze it. Experts found that in the first and fourth quarters, Hainan's atmospheric air mass mainly came from the mainland, and from the wind direction, it mainly blew northeast wind and north wind. In the second and third quarters, Hainan mainly blows southeast wind, that is, the wind blowing from the sea.

By analyzing the atmospheric circulation path from June 65438 to/kloc-0 to October 24 this year, experts found that when Haikou was slightly polluted, its atmospheric circulation all came from Central China and South China, and pollutants migrated from these heavily polluted areas. When the air quality in Haikou was good in June 5438+1October this year, experts found that the air mass mainly came from the Taiwan Province Strait. Yue Ping believes that from the trajectory of atmospheric clouds, the air in Haikou and some cities and counties is "slightly polluted", mainly due to the long-distance migration of pollutants.

Yue Ping also provided evidence. In order to fully understand the air background quality in a wide range that is not affected by local pollution sources, the Ministry of Environmental Protection built a national ambient air background station in Atuling, Wuzhishan, Hainan Province on 20 10. During the month of 65438+ 10 this year, when Haikou was slightly polluted, the data monitored by Atuling National Ambient Air Background Station was also very large, especially on June 24th of 65438+ 10, the air quality data monitored by Haikou and Sanya were the highest, and the data monitored by Atuling National Ambient Air Background Station was 3-7 times as high as usual. "There is no pollution in Atuoling, so there should be no abnormality." Yue Ping believes that this further shows that long-distance migration has caused "light pollution".

The phenomenon of local climate "inversion" aggravates pollution.

Yue Ping believes that the unfavorable conditions of local climate inversion have also aggravated pollution.

In general, the atmospheric temperature decreases with the increase of altitude, that is to say, below a few kilometers, the lower atmospheric temperature is always high and the upper atmospheric temperature is low, which is "top-heavy". This kind of atmospheric stratification is prone to rolling up and down, that is, "convection" movement, which can transport pollutants near the ground to high altitude or even far away, thus reducing the degree of urban air pollution. It has little impact on human health. However, under some weather conditions, the atmospheric structure above the ground will have an abnormal phenomenon that the temperature increases with the height, which leads to the stability of the atmospheric stratification, which meteorologists call "inversion".

Experts said that Hainan is prone to "inversion" in the first and fourth quarters. The sky above the city is like a thick quilt, which reduces the air flow between the upper and lower floors, and there is no way for air pollutants near the ground. The more they accumulate, the more serious the air pollution will be.

"Everyone clearly felt that in the fourth quarter of Hainan, the air was dry, the rainfall was less, and all kinds of dust in buildings, roads and construction increased. Air masses bring pollutants from the inland, and unfavorable meteorological conditions further aggravate pollution, and air quality is affected to some extent. " Yue Ping said.

Local pollution sources must be controlled.

For the recent "mild pollution" of air quality in some cities and counties in Hainan, Yue Ping believes that it cannot be "recruited" because the migration of foreign pollutants is the main cause. Although local pollution sources will not cause "light pollution", they must be paid attention to. "Site construction, demolition, motor vehicle exhaust emissions, etc. They are all problems that will bring air pollution. "

It is estimated that by the end of August this year, the number of motor vehicles in Haikou will be 456,000, including 363,000 cars, accounting for about 60% of the total number of cars in the province, which is 8 times higher than that of 5438+0 in 2006. Moreover, most motor vehicles are concentrated in the central city, and some old and over-standard vehicles are still driving on the road, so the exhaust emissions of motor vehicles have a great impact on the ambient air quality of our city.

At the same time, road congestion has intensified. It is estimated that there are nearly 500,000 motor vehicles (including foreign vehicles) driving in the downtown area of Haikou with dozens of square kilometers, and the traffic congestion problem is becoming increasingly prominent. Relevant research shows that motor vehicles emit the most pollutants when the speed is slow and waiting (that is, idling), and the aggravation of road traffic congestion leads to the increase of motor vehicle exhaust emissions.

"This season, the impact of roasted betel nuts in Qionghai and Wanning on air pollution is still relatively large. There are also roadside barbecues and kitchen fumes in the city that are aggravating pollution. " Yue Ping believes that it is necessary to control local pollution sources and ensure the air quality in Hainan.