PM2.5 in Beijing

The PM2.5 index in Beijing has become a topic that people worry and talk about every winter. Indeed, the air quality in Beijing has been very poor in recent years, and PM2.5, one of the standards for measuring air quality, has gradually gained people’s attention.

PM2.5 is the particulate matter with aerodynamic equivalent diameter less than or equal to 2.5 microns in ambient air. In general, PM2.5 has several sources. Natural sources include soil dust, plant pollen bacteria and more. Volcanic eruptions, forest fires will also transport a large number of fine particles to the atmosphere. Anthropogenic sources include all kinds of fuel combustion, such as power generation, metallurgy and other industrial processes. Fumes emitted during heating and cooking, and tail gas discharged to the atmosphere when various types of vehicles use fuel during operation. In addition, atmospheric chemical reactions also produce PM2.5.

PM2.5 index as a measure of air pollution control standard was proposed by the United States in 1997. PM2.5 has an important impact on air quality and visibility. Fine particle size is small, rich in a large number of toxic and hazardous substances and stay in the atmosphere for a long time, the transmission distance, and thus greater impact on human health and atmospheric environmental quality.

It has great harm to organs such as the lungs and respiratory tract. About 2.1 million people worldwide die each year due to the increase of PM2.5 and other particulate matter concentrations. The poisoning incident on December 5, 1952, was one of the most painful moments in London’s history when at least 4,000 people were killed by the toxic smog. Numerous residents of London were having trouble breathing. Traffic was paralyzed for many days and millions were affected. In 2013, WHO first identified PM2.5 as carcinogenic. The impact of PM2.5 on the overall climate may be even worse. Blue sky and white clouds have become less than before. Heavy rains may occur under extreme circumstances.

Since June 2012, the Beijing Municipal Environmental Protection Bureau and other agencies have conducted PM2.5 source analysis and obtained the main sources of PM2.5 in Beijing. Among PM2.5 sources in Beijing, the contribution of regional transmission to PM2.5 sources in Beijing is as high as 28-36%, and the contribution of local pollution discharges is 64-72%. Among the contribution of local pollution, motor vehicles, coal-burning, industrial production and dust-lifting are the major sources, accounting for 31.1%, 22.4%, 18.1% and 14.3% respectively. Other emissions from catering, automobile repair, livestock and poultry farming, architectural coatings and others account for 14.1% of the whole PM2.5.

According to the research results, experts give their suggestions. First, since motor vehicles, coal combustion, industrial production and dust are the four main aspects of Beijing PM2.5 sources, they must be strictly controlled, especially the motor vehicle pollution. Second, the contribution of regional transmission to PM2.5 sources in Beijing is as high as 28-36%. To improve the air quality in Beijing, it is urgent to effectively carry out regional joint prevention and control and reduce the total amount of pollutant emissions in the region.

On May 24, 2012, China announced the Implementation Plan of the First Phase of New Air Quality Monitoring Plan, requiring 74 cities across the country to complete the commissioning of PM2.5 “National Control Point” monitoring by the end of October. On October 11, 2012, after the promulgation of the new Ambient Air Quality Standard, the environmental protection authorities have clearly set forth the “three-step” target of implementing the new standard. According to the plan, by the end of 2012, key areas such as Beijing, Tianjin and Hebei Province, the Yangtze River Delta and the Pearl River Delta, as well as municipalities directly under the Central Government, cities specifically designated in the state plan and capital cities under the state capital will be monitored and the data released according to the new standards. At present, at least 195 sites across the country have completed the installation and commissioning of PM2.5 instruments and 138 sites have formally started PM2.5 monitoring and data release.

We citizens should also make enough protections. We should reduce going outdoors in haze days. If needed, then wear a professional dust mask. In addition, we can take a small amount of vitamin D, keep the diet light, and try to reduce smoking or even stop smoking.

In recent years, with the efforts of relevant departments, the hazy days in Beijing have obviously decreased, and the air quality is gradually developing towards a good direction. However, due to the problem of low air pressure in winter, PM2.5 is not easy to spread after it is generated. Besides, traffic, heating and other factors are not further solved, so the haze weather is not completely eliminated. Though there are still many problems, it is believed that with the development of science and technology, a sunny winter in Beijing is just around the corner.

本文以“北京PM2.5”为话题展开。开篇点明此话题在北京热度不减，下一段介绍从广义上PM2.5的定义及来 源，包括自然源、人为源、大气反应，再介绍PM2.5监测指数的提出及危害，并以伦敦污染为例证，接下 来写北京的PM2.5具体来源及政府、个人的应对措施，最后表明PM2.5造成的雾霾天气虽有好转但并未消 失，在科技的发展下晴朗的北京指日可待的希望。