近年来，我国中部和东部地区受到长期严重的大规模雾霾天气的作用。整个华北、黄淮地区和长江流域都有不同程度污染。本篇文章介绍了什么是雾霾以及导致形成雾霾的主要因素。 In recent years, the central and eastern regions in China were frequently affected by serious long-term and large-scale haze weather. The whole north of China, Huang-Huai area and Yangtze River regions were polluted in different degrees. According to statistics, the land area which was influenced by the heavy fog weather reached 345 square kilometers in China’s central and eastern regions since 2017. More than half the national people have been badly affected in the aspect of daily life, enterprise production and transportation (Luo Liangqing and Xie Lizhi 319). Especially in winter, Chinese people suffered from haze badly. Many people were infected with diseases and nobody dared to walk out of doors without respirators.
What is haze? Haze weather is a combination of fog and haze. The main ingredients of haze include sulfur dioxide, nitrogen oxide and inhaled Particulate matter. Among the three matters, sulfur dioxide and nitrogen oxide are gaseous pollutants while inhaled particulate matter is solid contaminants.
From the meteorology, the fog and haze are two different meteorological concepts and meteorological phenomena (Li Liangzhi and Li Xin 1979). Fog is condensed by ice crystal or small water droplets suspending in the air. And its composing state is aerosols system which often occurred in autumn and winter. When the horizontal visibility is less than 1,000 meters, the weather phenomena caused by large-scale water vapor condensation is called fog. If the horizontal visibility is between 1,000 meters and 10,000 meters, we call it mist. As for haze, its main components are sulfuric acid, nitric acid, dust, organic carbon oxides and other particles. When the horizontal visibility is less than 10,000 meters which caused by this aerosol system, we call this weather phenomena haze or dust-haze (Li Peng 323).
Fog is indirectly related with air pollution. On one side, it indeed doesn’t do harm to our body and health. But for those patients with severe asthma or emphysema, fog will make them uncomfortable. On the other side, some contamination particles are easily heaping up, slowing down air motion thus getting air quality worse. Haze has a direct relationship with air pollution because those suspended particles in the air can damage human body. Despite that we can’t see them with naked eyes, they can enter our body through respiratory system and even adhere to our lungs. The consequence is that our immune systems are undermined and eventually we are infected with diseases.
The different sizes of fog particles’ diameter lead to different extents of injury. PM10, also called inhalable particles which are able to enter the upper respiratory tract but less harmful to human body compared with other particle matters. PM2.5, repairable particles, can directly enter into bronchus after being absorbed by human body. It may trigger asthma, bronchitis and cardiovascular diseases. Besides, there are plenty of poisonous and harmful substances so it’s more harmful than PM10. PM1 is with cancerogenic substance and can enter into human blood (Li Peng 323).
What kind of activities can result in haze especially for China in recent years? Well, it can be explained from perspectives of human factor and natural factor. Nevertheless, what human beings did mostly accounted for the cause of haze. “Fog-haze has a close relationship with the accumulation of mass contaminants, adverse weather conditions and regional transport of contaminants ”(Wei Li, Yan Shi, Chunli Song 3678-3682 ).
The large amount of high energy-consuming enterprises and high pollutive industries sharply increases pollutants. The thermal power in China accounts for more than 90% of whole power generation and 85% of thermal power is almost coal-fired power. Fossil fuel combustion and energy use produce sulfur dioxide and carbon dioxide which lead to accumulation of mass contaminants. Cement, steel, manufacturing and other industries are widely distributed in north China area like Beijing-Tianjin-Hebei region where pollution level is 3.7 times of the national average level. Shanxi Province and Inner Mongolia autonomous region are also concentrated with coal chemical industries and thermal power enterprises. It is same with Pearl River Delta and Yangtze River Delta. Both are areas concentrated with highly polluting production industries (Wu Ping, Yu Wenzhou 453 ).
Some adverse weather conditions has also gradually become one of reasons of haze weather. Some cities are dry and rainless but windy in winter and early spring especially in north China. Such weather can easily make flowing dust pollution. The majority of China’s cities are in the rapid development of infrastructure construction. Building, demolition, road construction and other work process generate more and more raise dust. Combine the two factors it’s not strange that raising dust pollution is more and more serious. Good weather conditions are conducive to the spread of waste gas and polluted particulate matters. And vise versa thus leading to as well as aggravating the occurrence of haze disaster. Three changes of meteorological conditions are the factors which lead to serious consequences. The decrease of the annual average rainy days, the decrease of the annual average wind speed and the increase of calm wind days (Wang Tengfei 15). Hence climate effect can also be an important factor to hazy weather.
|
