What exactly is PM2.5? Into the lungs into the blood!

PM2.5 enters the blood. The macrophage in the blood thinks it is a bacterium and immediately comes to swallow it. Macrophages ingest bacteria, bacteria are alive, and are food for macrophages. However, PM2.5 is inanimate, and macrophages swallow it, as if the tiger had swallowed the stone and was eventually killed, then our immunity was reduced.

Let's work together to understand what PM2.5 means in the misty days.

PM2.5's "PM", particulate matter is an abbreviation for English words, translated as "fine particles."

The "2.5" of PM2.5 is 2.5 microns, 1000 microns = 1 mm, and 2.5 microns is equivalent to 1/20 of the diameter of the hair filament. Therefore, fine particles with a diameter of 2.5 microns are invisible to the naked eye.

PM10 is a finer particulate matter than PM2.5. Its diameter is as large as 4 times, but its volume can be more than 4 times. According to the spherical volume formula, the volume of PM10 is 64 times that of PM2.5, which is so much larger than that of PM2.5. The naked eye is still invisible.

Particles larger than PM10 are PM50. The volume of PM50 is 8000 times the volume of PM2.5 and is visible to the naked eye. At home, a burst of sunlight is coming in. There are countless fine dust in the light column. It is PM50 and particles larger than PM50. On the table, there was a layer of gray, which are much larger than PM50 particles.

PM50, PM10, and PM2.5 are three critical values. There are not only three kinds of particles in the air, but particles of any diameter and length above 50 μm.

(Seeing the pillar of light means that the air in our city has been polluted!!!)

50 micron is a critical value that is visible to the naked eye and can enter the nasal cavity, but cannot continue to advance. The nose hair in our nose looks dense, but it seems sparse for the PM50. Nose hair can block PM100, PM75, but can not stop PM50. Blocking PM50 is the cilia of nasal mucosal cells. These cilia are invisible to the naked eye, so they can block the PM50. Moreover, the mucus secreted by the mucous membranes in the nasal cavity can also stick the PM50 and prevent them from moving forward.

Accumulated to a certain extent, we want to blow your nose and dig your nose, but don't be in the crowd.

10 microns is the critical value that can reach the throat, so fine particles below PM10 are called "inhalable particles." The throat is the terminal of PM10. The mucus secreted by the mucous membranes on the surface of the throat will stick to them. Each mucous cell has 200 cilia (which is invisible to the naked eye), and it keeps swinging upwards like a dragon boat. . Our natural physiological function is to prevent the PM10 from going down.

PM10 accumulates in the upper respiratory tract where the throat is located. The more accumulation, the more mucus is secreted. Accumulated to a certain extent, we want to spit. Therefore, you should vomit, do not swallow, and swallow.

2.5 microns is the critical value that can reach the alveoli. PM2.5 fine particles, the upper respiratory tract can not stop, they can smoothly down into the bronchioles, alveoli. Our respiratory system is like the root of a plant. From the top down, the trachea divides the bronchus. The bronchus divides the dense bronchi. The dense bronchioles are accompanied by dense alveoli. The number of alveoli is three to four hundred million. The inhaled oxygen eventually enters the alveoli, passes through the walls of the alveoli, enters the capillaries, and enters the entire blood circulation system.

The PM2.5 that we inhale into is too small to enter the alveoli and enter the capillaries through the walls of the alveoli to enter the whole blood circulation system.

PM2.5 carries many harmful organic inorganic molecules and is the source of illness. Bacteria are known to be the source of the disease, PM2.5 and bacteria have a ratio.

PM2.5 is a fine particle with a diameter of 2.5 μm, and bacteria are micron-sized organisms, which are mostly 1 μm, a few μm, and a dozen μm. That is, PM2.5 and bacteria are generally sized.

When bacteria enter the bloodstream, macrophages in the blood (a type of immune cells) immediately come in and swallow it. It will not cause sickness. This is like a tiger eating chicken.

PM2.5 enters the blood. The macrophage in the blood thinks it is a bacterium and immediately comes to swallow it. Macrophages ingest bacteria, bacteria are alive, and are food for macrophages. However, PM2.5 is inanimate, and macrophages swallow it, as if the tiger had swallowed the stone and was eventually killed, then our immunity was reduced.

Not only that, macrophages that have been killed, but release a substance that can cause inflammation of cells and tissues. It can be seen that PM2.5 is more pathogenic than bacteria. The more PM2.5 that enters the blood, the more likely we are to get sick.

PM2.5 harm to human body

1, cause respiratory obstruction or inflammation

Studies have shown that 75% of particles below 2.5 microns are deposited in the alveoli. We can imagine that sand is in my eyes and my eyes become inflamed. The depth of the respiratory system is also a sensitive environment. Fine particulates remain in the respiratory system as foreign objects for a long period of time. It also makes the respiratory system inflamed.

2, pathogenic microorganisms, polycyclic aromatic hydrocarbons, oil smoke, etc. take "sweep" into the body cancer

In addition to his own “doing bad things,” fine particulate matter is like a car that can freely enter the respiratory system. Other pathogenic substances such as bacteria and viruses ride “drift” into the depths of the respiratory system and cause infection.

Do not think that as long as you stay away from the bad eating habits of big fish and fish, you can hide blood vessel diseases. Fine particles also have many “methods” to induce cardiovascular diseases. For example, fine particles can enter the blood directly and induce thrombus formation. Another indirect way is that after the fine particles stimulate the respiratory tract to produce inflammation, the release of cytokines from the respiratory tract causes vascular damage, which eventually leads to the formation of thrombi.

Epidemiological investigations have found that PAHs in urban airborne particulates are associated with morbidity and mortality from lung cancer in residents. When PAHs enter the human body, fine particles play a role as a “shut-down”. Most of the PAHs in the atmosphere are adsorbed on the surface of particulates, especially those with a particle size of 5 mm or less, on large particles. There are few PAHs. In other words, the more fine particles in the air, the more opportunities we have for exposure to carcinogens—PAHs.

3, affect the fetal development caused by defects

There are some findings that make people more worried. In recent years, some reports have shown that human fertility is decreasing, and environmental pollution is considered as the culprit.

A survey from northern Bohemia investigated pregnant women exposed to high concentrations of PM2.5 and found that high concentrations of fine particulate matter may affect embryonic development.

More studies have found that atmospheric particulate matter concentrations are associated with increased perinatal births, neonatal mortality, low birth weight, intrauterine growth retardation (IURG), and congenital dysfunction.

4, PM2.5 particles can be exchanged into the blood vessels through the blood

In 2009, an experiment collected PM2.5 in the urban air of Beijing, and the human lung alveolar epithelial cell line (A549) was used as a model for toxicological studies.

In this experiment, a comparison of 25, 50, 100, 200 μg/ml, and other exposure conditions found that PM2.5 can cause inflammatory damage to these cells as the concentration of the drug increases.

Pan Xiaochuan, a professor at the School of Public Health of the Peking University School of Medicine, published a paper saying that from 2004 to 2006, when the daily average concentration of PM2.5 in Peking University campus observation sites increased, the cardiovascular disease was found in the Third Hospital of Peking University, about 4 kilometers away. The number of emergency patients also increased.

“We analyzed the collected data using time series analysis and found that if the concentration of PM2.5 increases by 10 micrograms per cubic meter, the number of emergency patients in hospitals with hypertension will increase by 8%, and cardiovascular disease will increase.”

The most serious pollution in East China! ! !

The World Health Organization (WHO) believes that PM2.5 less than 10 is a safe value, and all of these regions in China are higher than 50 and close to 80!

WHO put forward a very strict PM2.5 standard for all countries, and most cities in the world have failed to meet this standard. For developing countries, WHO has also developed guidelines for three different stages. The first stage is the widest limit. The new standard PM2.5 is consistent with the limit, while PM10's previous standard is wider than the first. The target value for the first phase is also increased by the new standard, which is in line with the WHO's first phase limit.

Air quality index

The Air Quality Index (AQI) is defined as a dimensionless index that quantitatively describes the air quality status. The Individual Air Quality Index (IAQI) is also specified for individual pollutants.

Using the air quality index can directly assess the quality of the atmospheric environment and guide the control and management of air pollution.

Air quality is divided into five levels according to the air quality index. Corresponding to the six categories of air quality, the greater the index and the higher the level, the more serious the pollution is, and the greater the harm to human health.

0～50 I excellent activity

51～100 II Liang

101-150 III1 Mildly aggravated symptoms in susceptible people with light pollution. Irritation in healthy people. Cardiac and respiratory diseases should reduce physical exertion and outdoor activities.

151~200 III2 Mild pollution

201 to 250 IV1 Significantly increased symptoms of moderately contaminated heart disease and lung disease, reduced exercise tolerance, and symptoms commonly seen in healthy people. Older persons and patients with heart and liver disease, lung disease should reduce physical activity

251~300 IV2 Moderate heavy pollution

301-500 V of heavily polluted healthy people have reduced exercise tolerance and obvious strong symptoms. Some elderly people and patients with advanced diseases should stay indoors to avoid physical exertion. The general population should minimize outdoor activities.