PM25英文介绍甄选

PM2.5英文介绍（优选.）
PM2.5
Airborne particles, the main ingredient of haze, smoke, and airborne dust, present serious air quality problems in many areas of the world. This particle pollution can occur year-round—and it can cause a number of serious health problems.
Basic Information
PM，an abbreviation for Particulate Matter, refers to liquid or solid particles suspended in the air. Depending on their origin and visual appearance, aerosols have acquired different names in the everyday language.The name PM2.5 denotes that it includes all particulate matter that has an aerodynamic diameter of 2.5 microns or smaller.
2.5 micrometers is approximately 1/30 the size of human hair.
Compare with big particulate matter, ultrafine particulate matter due to the large surface area, strong surface active. The toxic heavy metals (As, Cd, Cr, Pb, Hg, Se, Sn, Ni, etc.), the acidic oxides, toxic and hazardous organic pollutants (polycyclic aromatic hydrocarbons of PAHs, dioxins PCDD / Fs) to be carcinogenic, mutagenic substance with stronger enrichment, which is more easily attached to bacteria and viruses in the environment, so the particles are greater impacted on the ecological environment and human health, it is particularly important to strengthen the control of emissions of ultrafine particulate matter.
The sources of PM2.5 include fuel combustion from automobiles, power plants, wood burning, industrial processes, and diesel-powered vehicles such as buses and trucks.These fine particles are also formed in the atmosphere when gases such as sulfur dioxide, nitrogen oxides, and volatile organic compounds (all of which are also products of fuel combustion) are transformed in the air by chemical reactions. Another source is natural source, such as pollen and spores, soil dust, sea salt, forest fires, volcanic eruptions and etc.
The harm of PM2.5
It has mall particle size, higher degree of dispersion, good stability in the air, and in the atmospheric dwell time of up to one month, and can be long-distance transmission. So it can cause atmospheric visibility. Besides it Intensifies atmospheric acid rain and photochemical smog.
It has the complex chemical composition of the particulate matter.When these material deposited in the lungs, some soluble directly into the blood, resulting in blood poisoning. Lead to cardiovascular disease, and damage to the brain, causing nerve damage that can affect children's intelligence. Which contained some trace amounts of heavy metals can act on DNA to cause DNA damage and fracture of cancer. Increased levels of fine particles in the air as a result of anthropogenic particulate air pollution "is consistently and independently related to the most serious effects, including lung cancer and other cardiopulmonary mortality." The large number of deaths and other health problems associated with particulate pollution was first demonstrated in the early 1970s and has been reproduced many times since.On December 5, 1952, toxic fog event is the most painful moments in the history of London. Smog killed at least 4000 people, many local people breathing difficultly, and the traffic paralysis appeared for many days, millions of people affected.According to a report the WHO published that 2.1 million people died because the PM2.5 pollution。

The pollution of PM2.5 decreased the average life expectancy for five years.
The pollution situation in China
With the rapid development of economy and society, the present pollution situation is very serious, for example, coal consumption rose sharply, vehicle quantities increased dramatically, NOx and VOCs emissions grown significantly, O3 and PM2.5 pollution aggravated. It has not been solved completely for PM10 and total suspended
particles (TSP) pollution, at the same time it was serious for PM2.5 and O3 pollution in the region of Beijing-Tianjin-Hebei, Yangtze river delta, pearl river delta, and so on. In September 2011, the WHO declared a global air pollution city report shows that China's air quality ranking is the 77th in 91 countries. Although it has no comprehensive monitoring data for PM2.5, the related monitoring has been carried out. The 30 data were selected and analyzed for PM 10 from October to November 2012.
Air pollution index for Beijing, Shanghai, Guangzhou and Chongqing of China are shown in a date. The four cities were selected because of their serious PM pollution and different region location. From this it can be reflected to the whole China. As the Shown from the date, the air pollution index average value is 92.8, 74, 67.9 and 75.1 for Beijing, Shanghai, Guangzhou and Chongqing, respectively. PM10 is prior and main pollutant. For Beijing, PM10 pollution is more serious than other three cities. For Beijing, the sources of PM10 were soil/crustal, coal combustion, motor vehicle, oil combustion, the secondary particulate and biomass combustion, which contributed 21.3%, 18.2%, 16.5%, 14.7%, 6.6% and 22.8, respectively [4]. For Shanghai, the sources of PM2.5(no PM10 data) were soil/crustal, coal combustion, motor vehicle, oil combustion, steel and other, which contributed 11%, 9%, 22%, 2%, 18% and 37, respectively [5]. For Guangzhou, it showed that urban dust, coal combustion, oil combustion, the secondary particulate, biomass combustion, industrial emission and other were the sources of PM10, which contributed 20.7%, 14.3% ，17.8%，10.4%，6.3%，16.3% and 14.2%, respectively [6]. For Chongqing, the sources of PM10 were coal combustion, motor vehicle, road dust, cement, steel and other, which took 18.35%, 15.11%, 20.48%, 27.22%, 3.74% and 15.10%, respectively .
The solution
In Europe and other countries is mainly from SOx, NOx and the conversion of gaseous volatile organic compounds. International control measures to PM2.5 is to carry out comprehensive management of the first PM2.5, and to reduce the conservation of gaseous precursors. To improve air quality, Europe has introduced nearly 20 regulations and directives, and also developed other standards on motor vehicle and other polluted source emissions. Furthermore, Europe and USA actively changes the development model, and commits to achieving a win-win model of both economic development and environmental protection. Many cities in their countries has begun to shift heavy industry outwards and developed knowledge-intensive industries. Most of countries improve the energy structure, vigorously use clean energy, and develop transit-oriented traffic.
Recent years a new device on Particle Coalescence Device and PM2.5 Poly and Dust-removal System is proposed. A new device named Flue Gas Purification Device on Removal PM2.5 with Ultrasonic Agglomeration is proposed, which provides with an ultrasonic spray agglomerator in order to reunite PM2.5 into larger particles. They also announced a kind of new device on Tourmaline Negative Oxygen Particles Device on Purifying PM2.5 in Fuel Gas from Power Plant. The device uses a tourmaline O-generator, which can combine PM2.5 and O- into larger particles, and then enter into electrostatic precipitator and discharged from the chimney.
In western countries, wet electrostatic precipitator technology is mainly method to removal PM2.5 from industrial emission sources. It is more suitable for metallurgy, chemicals, building materials, petroleum and food processing industry. However, it needs higher cost. Atmospheric rainfall can effectively remove soluble PM2.5, this is because PM2.5 easily accumulate and grow due to moisture absorption. It is removed by sedimentation, and efficiency is about 40~67%.
Scale of heavy industry in China is the first one in the world, including power generation, coal conversion, steel, cement, chemicals and etc. So the key to reduce PM2.5 is to diminish PM2.5 emissions from fuel gases, comprehensively renovate the coal-fired small boilers, and accelerate the transformation of desulfurization and denitrification industries.
China has proposed the method of the exhaust gas-water multiphase cross-flow array variable temperature based on the principle that the particles in the boundary layer may move to the gas-liquid interface under internal source fields. This technology has been applied to Drilling Diesel Engine Exhaust, the removal efficiency is up to 91.4%. However, it needs lots of water, huge power consumption, and wide area, suitable to install near rivers and lakes.
The Ambient Air Quality Standard (GB3095-2012) was enacted on February 2012 in China. In consideration of the complexity source and component of PM2.5, and the increase of the motor vehicle, the difficulties in PM2.5 pollution and monitoring increase gradually.As a result, we should develop the particulate matter monitoring and controlling, enhance the research about the health effect and epidemiology studies for the further environmental decision-making. In order to control PM pollution, the control measurements are followed, such as determining environmental capacity according to the different region character, implementing zone integrated and making the improvement target, emphasizing scientific planning and ensuring the multiple investment, optimizing the economic structure and implementing cooperative pollution control, strengthening monitoring supervision, promoting the policy implementation, and so on.
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