The key to eliminate ash is energy saving and emission reduction

In the autumn and winter season of Sinochem’s new Web site, a series of weather conditions in some cities nationwide made people know the term “PM2.5”, and a series of problems related to PM2.5 also surfaced. The environmental protection department here said that at present, China has not yet effectively monitored PM2.5. Because of this, the public opinion of the moment was different, and many people thought that PM2.5 was the culprit of the hazy weather and naturally pushed the responsibility for the ashes to chemical industries and other polluting industries. What exactly is PM2.5 and what is its cause? Who is the initiator of the ashes? Recently, the reporter interviewed some experts on these issues.

According to experts, PM2.5 refers to particles in the atmosphere that are less than or equal to 2.5 microns in diameter, and their diameter is less than 1/20 of the diameter of the hair. In the Beijing Blue Sky project experiment conducted in 1998, it was confirmed for the first time that ash was mainly composed of PM2.5. Tang Xiaoyan, a professor at the School of Environmental Science and Engineering at Peking University, explained that dust particles consisting of particles such as dust, helium, and ytterbium tend to scatter light with a longer wavelength, and therefore appear yellow or orange-gray. Due to the severe air pollution in the urban areas, earthworms can occur frequently, and there are many black carbon particles in the polluted atmosphere, making the entire atmosphere orange-gray, so we call it "gray weather." According to the provisions of the World Meteorological Organization, the weather with atmospheric visibility less than 10 kilometers and relative humidity less than 90% is hazy. In recent years, ashes have become the biggest pollution problem in many cities in China, and PM2.5 is the key.

Not long ago, the environmental protection department’s doubts about the people indicated that due to technical reasons, China is still unable to effectively monitor PM2.5. Therefore, there has been a large gap between the monitoring data of the environmental protection department and people’s feelings.

The person in charge of the Ministry of Environmental Protection pointed out that the phenomenon of ashes is actually a kind of comprehensive atmospheric pollution phenomenon. At present, new changes have taken place in China's air pollution characteristics. Coal-based energy consumption has risen sharply. At the same time, the number of motor vehicles has increased dramatically. The emissions of NOx and VOCs have increased significantly in developed regions, and PM2.5 pollution has intensified. Professor Shao Min, deputy director of the School of Environmental Science and Engineering at Peking University, also stated that urban ashes were rarely seen in the past and did not attract people’s attention. In recent years, due to the rapid expansion of economic scale and the acceleration of urbanization, atmospheric particulate pollution has become increasingly serious.

So why are the ultrafine particles in the air increasing? According to analysis of environmentalists, this is directly related to the consumption of fossil fuels. Excessive proportion of coal-fired power generation in China is one of the important reasons for the increase in PM2.5. China's energy consumption has more than doubled in the past 10 years, and the proportion of coal in the energy structure has exceeded 70%. China's coal consumption rose from 1.445 billion tons of standard coal in 2004 to 3.24 billion tons of standard coal in 2010, which is three times that of the United States and six times that of India. It is the world's largest coal consumer.

According to the data, there are many unremovable ultra-fine particles in the coal dust emitted by combustion, and the combustion of coal emits sulfur dioxide and nitrogen oxides to carry out complex atmospheric chemical reactions with other pollutants in the air to form sulfate, yttrium salt secondary particles. The conversion of gaseous pollutants into solid pollutants has become a major cause of the increase in PM2.5. For this reason, relevant environmental protection experts have appealed that China should immediately carry out coal pollution control, and at the same time vigorously develop new energy and clean energy, and get rid of excessive dependence on coal as soon as possible.

There is also a view that not only the traditional high-emissions industry has caused hazy weather, but the rapid development of some emerging industries has also exacerbated the deterioration of the atmospheric environment.

Some people say that the rapidly rising photovoltaic industry is a high-energy-consuming and highly-polluting industry, because most photovoltaic cells are now made of polysilicon, and exhaust gases and waste materials emitted from polysilicon production process are seriously polluting the environment. China's Renewable Energy Association Secretary-General Meng Xianji told reporters that many foreign polysilicon manufacturers have already solved the problem of high pollution and high energy consumption in the production process. However, some of the key steps and technological processes involved in the production of polysilicon in China, such as the recycling of exhaust gas and waste materials, and the reduction of energy consumption, are still being fully implemented. They can only rely on domestic companies to explore and research their own technologies.

In the face of the increasing haze in our country’s cities, our government is taking active and effective measures and actions. Vice Minister of Environmental Protection Zhang Lijun expressed at the 7th International Air Quality Management Conference on November 10th that China's PM2.5 atmospheric environmental quality standard - "Ambient Air Quality Standard" is about to be issued, which will be the first time for China to enact PM2.5 national environmental quality standards. The new standard is planned to be fully implemented in 2016. However, according to the relevant laws and regulations in China, the Ministry of Environmental Protection can designate some cities to conduct monitoring in advance, and also encourages cities with conditions to take the initiative to carry out monitoring in advance.

The person in charge of the Department of Science and Technology Standards of the Ministry of Environmental Protection also emphasized that in order to strengthen atmospheric environmental protection and improve the quality of the ambient air, whether it is controlling PM10 or PM2.5, the key to improving environmental quality is still reducing emissions. Only emissions are low, and pollutant concentrations are low. Reduced, air quality can really improve.

The reporter learned that at present, many petrochemical companies have begun to pay attention to the forthcoming atmospheric environmental quality standards, especially some powerful large-scale enterprises have tried to take the company's environmental protection work to a deeper level.