PM2.5 invisible killer

Overcast weather so more and more Chinese PM2.5 a public notice in English and numbers jargon. In fact, many Chinese and foreign scholars have already confirmed that it is hidden in the air, not only will harm human health, but also to society difficult to restore economic losses.The so-called PM2.5, is airborne particulate matter, less than 2.5 microns in diameter. Because these particles are too light, natural subsidence fall to the ground hard, but long-term floating in the air, not only small to see, but small enough to be even directly into the blood into the alveoli, and the body's cells "struggle" and harm These cells. To some extent, calling it "the killer" is not an exaggeration.
PM2.5 how to "conviction"
Scientific information from the public to see, a lot of research on PM2.5 focused on the lungs.
Researchers start from the lungs of toxicology: the PM2.5 daily for 4 1 rats exposed continuously for 3 days. Lung lavage fluid of these rats and lung tissue biopsy analysis found that, PM2.5 can cause lung vascular permeability changes in pulmonary cell damage and increased oxidative stress, in the high dose exposure group, exudation of inflammatory cells in rat lung, pulmonary edema interval.
Collected in 2009 an experiment in the atmosphere in Beijing urban PM2.5, human alveolar epithelial cell line (A549) as a role model for toxicological studies. In this experiment, to 25,50,100,200 μg / ml, such as different exposure conditions found that, with increasing exposure concentrations, PM2.5 can cause these cells to inflammatory injury.
"All evidence suggests that, at present these small particles on the cell injury is public opinion." China Academy of Engineering School of Shi Wei Fu-sheng told reporters that when these small things into the body, usually directly to the bronchi and alveoli, or even into the blood, the adsorption of heavy metal oxides PAHs and other carcinogenic substances or harmful.
A study published this year by a nickel-mining and refining area for PM2.5 collection area. The researchers found that nickel-polluted atmosphere, PM2.5 nickel dose is 65 times the experimental control area, the long-term exposure to PM2.5, the high concentration of nickel will increase the damage to cells. The experiments used to test the cells called "endothelial cells", is a continuous coating layer of the lining of blood vessels in the cell populations. In the researchers view, not just blood and tissue within the cortex of the barrier, the damage and dysfunction with a variety of diseases are closely related, including hypertension, coronary heart disease, diabetes, chronic renal failure.
Peking University School of Public Health, Professor Pan Xiaochuan published a paper in 2004 to 2006, when the Peking University campus daily average concentration of PM2.5 observation points increases, about 4 kilometers away in Peking University Third Hospital, cardiovascular disease also increased the number of emergency patients.
"We use time-series analysis of data collected, analyzed, PM2.5 concentration of 10 micrograms per cubic meter, the hospital's emergency department patients with hypertension class will increase 8%, cardiovascular disease will increase." Pan Xiaochuan said.
In March, the Shanghai Environmental Protection Bureau of a project to study the quantitative evaluation of the residents of a city health hazards caused by PM2.5 and its economic losses. The results show that the city's haze pollution factors in 2009 residents of PM2.5 health hazards caused by a total of 2.461 billion yuan of economic losses, loss of 377 yuan per capita, the city accounted for 0.17% of GDP in 2009.
Studies have shown that from the economic losses caused by various diseases of view, cases of the respiratory system caused by the biggest economic losses, accounting for 76% of the total economic losses, but the disease than asthma, respiratory diseases are more susceptible, in 2009 the city asthma prevalence of 19,589 cases. The study also showed that air pollution caused by the different regions of the residents of different health risks of economic losses, such as the 2004 Tangshan air pollution harmful to the health of residents, per capita economic losses of up to 414 yuan / person; Liaoning Fushun residents' health caused by air pollution, loss of small, is 153.15 yuan / person; the same period, Shanghai residents' health caused by air pollution, losses of up to 315.95 yuan / person.
PM2.5 how to "attack"
Wei Fu-sheng told reporters that, in general, more than 10 microns in diameter particles, will be blocked out in the nose; diameter of 2.5 microns to 10 microns between the particles can enter the respiratory tract, but with the spitting, sneezing is part of the excreted ; and less than 2.5 microns in diameter, fine particles, but it will pass the lower respiratory tract, is less than 2.5 microns can enter into the alveoli, and exchanged into the body through blood vessels.
If the enlarged view of these small particles, they are not necessarily circular or square, and irregular shape. Said Wei Fusheng, a small part of these particles is naturally formed in the dust, the vast majority of secondary pollution caused by human behavior, such as sulfur dioxide, nitrogen oxides, ammonium sulfate, ammonium nitrate and other particles. Many of these particles is due to incomplete combustion of fossil fuels produces organic carbon, sometimes in high-temperature coal-fired power plants to generate carcinogens in the cooling of these small particles are adsorbed into the body.
Said Wei Fusheng, such small particles is difficult to natural subsidence, in the air, stay for a week or even months, have their own effects on the respiratory system, causing coughing, discomfort. And small particles on the adsorption of carcinogens, but also lead to high incidence of cancer.
December 5, Tsinghua University, Shi Yigong Bowen said in the past two years, he often painful because of air pollution. His chronic pharyngitis gradually increased since the beginning of 2010, encountered pollution days, "like throat blocked a thing, the pharynx does not survive, but do not spit out, very hard to accept. I do not know how many like me, put this in a serious air pollution. "
Appears in the Pan Xiaochuan, a variety of adsorbed particles was more deadly toxic chemicals.
He told reporters, these because industry and other human activities, incomplete combustion and emission of small particles, itself consists of a certain composition of silica and carbon. In other words, they are "born" of the moment, may be innocent harmless, the only feature that is too small, too. However, the same concentration, the finer the particles, the number more. Than PM10, PM2.5 to be several times the surface area, adsorption of toxic substances in the air will be more.
When the adsorption of PM2.5 carcinogen, there is carcinogenic effect; adsorption of teratogenic, there are teratogenic effects. It is through the lower respiratory tract, deep into the lungs, and it carries the harmful gases, heavy metals will dissolve in the blood.
Since PM2.5 easier for the elderly and children who "get angry", the researchers are concerned about the "killer" may be close to them. One study found that living near main roads in Beijing urban children exposed to higher levels of individual PM2.5. And in 2008 published a paper in September, the National "Eleventh Five-Year" Technology Support Program funded projects, determination of Beijing elderly people in a community of pollutants in the winter when the level of exposure is higher.
Yigong Shi 2008 from Princeton University, chair professor positions for life to return the resignation of the incumbent president of Tsinghua University, School of Life Sciences, but two years, his mood "has been as good or bad air quality changes "because" everything is for our children. "
In his view, air pollution on children's development, mental health will be adversely affected. Frightening is that these effects will generally not be apparent for months or even years to detect, and perhaps some long-term air pollution by the people you will never be aware of its impact ... ... the most frightening thing is that ordinary people to air pollution there is not enough awareness, under normal circumstances would not take the initiative to appeal. While the patient is difficult to diagnose whether the air pollution caused by disease.
He said the pollution of air pollution more dangerous than others. First, the victim up. Unless living in the filter, everyone will suffer. Second, almost impossible to protection. We worry about pollution, you can install a filter of harmful substances; worried about food safety, you can choose some of the more secure food or washed before eating. There is no way to deal with air, because air pervasive, everywhere. Up is fitted in the office and home air filter, but the effect is limited.
How to "apprehend" PM2.5
PM2.5 everywhere, but people can not live in the hood yard. We hope the public, at least know that "rival" power to protect themselves.
Liu Changfeng located in Beijing, a Fortune 500 company to work. Spare time, he took the detector, to compare the subway, taxi, bus, cycling the four modes of transportation. He found that there is no second-hand smoke on the subway, there is no ground on vehicle exhaust emissions, and therefore PM2.5 value of the minimum. So he gave up riding in spring and autumn every year, try to take the subway. He found the office closed in PM2.5 values ​​acceptable to give up going out to eat lunch on the second floor in the office of the meal. He returned to his home, planted 27 pots of green plants, although his mind clear, this is of little use.
This instrument is the detection of natural knowledge that he asked the agency from Darfur borrowed, in Liu Changfeng view, this instrument by the humidity, the air can not be seen in the small water droplets and dust. So they are ready to replace equipment, making this test in a more scientific direction.
Pan Xiaochuan of the research team adopted a "most original" method "apprehend" PM2.5.
This method is like using "shrimp cage" catch "prey": the researchers used specialized sampling head, which is a membrane, the entrance surface of a certain large particles to enter, only the "small fish shrimp." can be captured in, come in to ensure that their leaving. This "shrimp cage" placed in the sampling point 24 hours later, brought weighing, the extra weight is the weight of small particles are.
Pan Xiaochuan said that with the current popular detector and other equipment for testing, the technical conditions is not perfect.
Environmental Science and Engineering, Fudan University, Atmospheric Chemistry Research Center, Zhuang told reporters that China's test of PM2.5, whether technically or economically not difficult. Fully mature technology with international technical standards, professional testing equipment for each of about 10 million, in Beijing, Shanghai, Guangzhou and other cities with such a device is completely capable.
Of PM2.5 in the apprehension and conviction, in fact, is not new. Wei Fusheng was the chief engineer of the China Environmental Monitoring Station, back in the 1990s carried out the impact of air pollution on respiratory health study. He told reporters that the United States has not yet developed policies for PM2.5.
Wei Fu-sheng told reporters that the United States, 1990s PM2.5 study from a theoretical point of view, the U.S. health sector development and environmental protection departments urged PM2.5 standard, but the industry sector and the entrepreneurs are against the government, there are some objections the sound. Because once the development of standards, criteria to determine the scope of the PM2.5 into governance, means that companies and society should pay a higher cost and price. Environmental protection departments to collect evidence, a lot of money and effort to carry out related research.
Wei Fusheng said the United States to develop PM2.5 standard game lasted nearly 20 years. (According to "China Youth Daily")