PPE

Do you know which place has the worst air quality?

Do you know where the air quality is the worst in your daily life and workplace

with the development of the city and the growth of the population, the urban subway is constantly built and expanded. At present, Beijing has 17 lines with an average daily passenger flow of more than 7 million, making it the fifth busiest subway city in the world. Subway brings us great convenience, but staying in the subway for a long time will also pose a great threat to our health

1. how dirty is the air in the subway

according to the latest survey of King’s College London published in the daily mail, the air in the subway is the dirtiest of all indoor and outdoor environments

researchers at King’s College London chose six healthy volunteers to carry air detectors with them to monitor the air quality wherever they went during the day. The monitoring results show that the air quality in the subway is the worst, with the PM2.5 concentration of 64 micrograms per cubic meter; The second is driving on the road, the value is 33; The next is: walk to the mall and playground, the value is 31; Cycling on the road in peak period is 26; The driving value in the tunnel is 21; Cooking in the kitchen is 19. Relatively speaking, the air quality in the garden and the home without lampblack is the best, and the PM2.5 value is not more than 1

according to the environmental quality analysis of Shanghai Metro Platform in 2009, the average concentrations of pm1.0, PM2.5 and PM10 in Shanghai test platform reached 234ug / m3, 293ug / m3 and 372ug / m3 respectively, and the concentration of particulate matter exceeded the standard seriously. The average concentration of PM10 in people’s Square Station is 825ug / m3, which is 3.3 times of the subway design specification and 5.5 times of the indoor air quality standard

compared with the outside of the subway, the interior of the subway is a relatively closed space, and the air exchange between the subway station and the outside can only be carried out through the entrance and exit of the station and the limited tunnel air shaft. When the peak population density increases in the morning and evening, the ventilation effect becomes worse and unbearable. Moreover, in a relatively closed space, people can produce 5 million small particles every minute when they move, such as falling dander, sneezing droplets, fibers on clothes, dust from soles of shoes, etc., which can be inhaled by people at any time

at the same time, the high density of people in the subway will release a lot of odor and carbon dioxide, and produce a variety of microbial bacteria. Coupled with poor ventilation and lack of sunlight, bacteria and other biological pollutants will survive and spread for a long time in the specific environment of the subway< Second, air pollution can be fatal, although the subway interior has been cleaned and disinfected, including the cleaning of the floor, seats and handrails. However, this kind of disinfection is far from enough. When the subway is running, microorganisms such as armrest, handle and seat bacteria are exchanged by passengers from time to time. Just disinfection in the garage is not enough to stop the spread of microorganisms Swedish medical professor Hahn Carlson published a paper in Sweden’s Science Daily, saying that the air composition in the subway system is very different from that on the ground. There are many kinds of harmful particles in the subway air, which can destroy the DNA structure of the human body and penetrate into the main human organs including the lung, brain, liver and kidney, 1t’s more harmful than car exhaust to the health of passengers. These harmful particles do not exist in the subway for a long time. Generally, the concentration of harmful particles is the highest in spring and the lowest in winter< According to Professor Carlson's research on the air of Stockholm metro, more than 5000 people die prematurely every year in Sweden due to the long-term inhalation of carbon, asphalt, iron and other small particulate pollutants. After research, it is concluded that there is an iron particle in the air of the subway, which has the greatest damage to the body DNA. When these iron particles enter the human organs, they will form a free radical in the human cells, which will not only harm the human genetic mechanism, but also increase the risk of cancer. Some harmful substance particles can also induce all kinds of inflammation. And this kind of particle is mainly produced by the friction between the wheel and the track< 1n order to ensure the air tightness of the car body and the requirements of interior decoration and energy saving, a large number of decoration materials and thermal insulation materials are used in the car. These materials will directly release a variety of chemical pollutants including volatile organic compounds into the car