Ten-faced “squeak” and need to wear a mask

In 2013, "Smog" became the key word of the year. In January of this year, the four haze processes covered 30 provinces (autonomous regions and municipalities). In Beijing, only 5 days were not haze days. According to reports, of the 500 largest cities in China, less than 1% of cities have reached the air quality standards recommended by the World Health Organization. At the same time, 7 of the 10 most polluted cities in the world are in China. On January 4th, 2014, the National Disaster Reduction Office and the Ministry of Civil Affairs first included the haze of health hazards into the natural disaster situation in 2013 for notification.

Nowadays, people wearing masks travel everywhere at the morning and evening peaks. The variety of masks, disposables, non-woven fabrics, and cotton cloth can all protect the “smoke”? Invited experts from Guangzhou Textile Inspection Institute to interpret protective masks for you.

1 PM2.5 is unknowingly one of the things that people have to pay attention to every day. So what is PM2.5?

PM2.5 refers to particles in the atmosphere that are less than or equal to 2.5 microns in diameter, and are also referred to as lung-infiltrating particles. Although PM2.5 is only a component of the Earth's atmospheric composition, it has an important effect on air quality and visibility. PM2.5 has a small particle size, is rich in a large amount of poisonous and harmful substances, has a long residence time in the atmosphere, and has a long transportation distance, and therefore has a greater impact on human health and atmospheric environmental quality. In February 2012, the State Council agreed to release the revised "Ambient Air Quality Standard" to increase the monitoring index of PM2.5.

Meteorologists and medical experts believe that the haze weather caused by fine particles is even more harmful to human health than sandstorms. Particles with a diameter of more than 10 microns will be kept out of the human nose; particles with a particle size of between 2.5 microns and 10 microns can enter the upper respiratory tract, but some can be excreted through sputum, etc. The internal fuzz blocker is relatively less harmful to human health; while the fine particles with a particle size of 2.5 microns or less have a diameter equivalent to 1/10 of human hair and are not easily blocked. After being inhaled into the human body, it directly enters the bronchus, interferes with gas exchange in the lungs, and causes diseases including asthma, bronchitis, and cardiovascular diseases.

2 Haze has become an important threat to human survival. People mainly adopt passive protection methods to resist smog attacks. What types of protective masks are there currently?

At present, the protective masks on the market include cartoon cotton masks, ordinary non-woven gauze masks, disposable non-woven masks, activated carbon masks, industrial dust masks, and PM2.5 masks.

Cotton cloth masks: basically only have the function of keeping warm and cold, the surface of the mask is relatively large, and it cannot resist the particles with a particle size of only 2.5 micrometers. The airflow resistance of some cotton masks is relatively large. People can easily cause breathing difficulties after wearing.

Gauze masks: Large pores, and poor adhesion on both sides of the nostrils. The gauze masks can block large particles by a layer of mechanical barrier, but are ineffective for PM2.5 particles. The thicker the mask is, the worse the breathability is. If you do not pay attention to hygiene, it will breed bacteria.

Activated carbon mask: Activated carbon has the effect of removing odors, but the protective efficiency of particles is not significantly enhanced. At the same time, activated carbon itself is also a kind of particle that may be inhaled into the body by the wearer. It is a harm to patients suffering from chronic respiratory diseases or the infirm.

Disposable masks: Filters are mainly for exhaled gases to prevent infections between doctors and patients. Face masks also do not meet the face shape design. In most cases, they can only play a role in shielding and can not effectively prevent PM2.5 particles.

Industrial dust mask: The filtration efficiency is over 90%, and it has good protection effect on PM2.5 particles. In order to reduce the resistance during exhalation, some exhalation valves are also provided. GB 2626-2006 "Respiratory protective equipment self-absorbing filter type particulate respirator respirator" standard according to the filter performance is divided into two types of KN, KP, KN type is only suitable for filtering non-oil particles, KP type is suitable for filtering oily and non- Oily particulate matter (the United States NIOSH 42 cfr part 84-solid standard is divided into "N", "R", "P" according to oil resistance, "N" refers to non-oily particles, "R" refers to, suitable for oiliness Or non-oily particulate matter, if used for the protection of oily particles, the use of time does not exceed 8 hours; "P" refers to suitable for oily or non-oily particulate matter). According to the filtration efficiency, it is divided into KN90, KN95, KN100, KP90, KP95 and KP100. The numbers in the models indicate the filtering efficiency of the mask.

PM2.5 protective masks: for the protective masks PM2.5 particles, because China has not yet introduced the standard for civilian masks, the quality of PM2.5 masks on the market are uneven, the price difference is relatively large, from more than ten dollars to hundreds of dollars Not equal.

3 What are the respirator masks for PM2.5? What is the protective principle? What are the advantages compared to traditional masks?

There are two types of protective masks for disposable PM2.5: disposable masks and filter-type masks. The use of disposable masks is hygienic, disposable, and cannot be cleaned; filter cartridges can be replaced multiple times and can be cleaned.

The protective principle of PM2.5 masks is through static electret on the surface of ultra-fine denier non-woven fabric, so that the surface produces a micro-electrostatic field. The pores of the filter material are like countless passive dust collecting electrodes, when the submicron in the airflow Particles (including PM2.5 particles) pass through the voids of the material and are trapped by the force of the electric field.

Most of the traditional mask materials used in the encryption state of the fiber (such as 28 layers of gauze), mainly rely on the mechanical barrier to the flow of dust in the air to intercept, to achieve the purpose of filtration. The disadvantages are that the removal of fine particles is not thorough enough, and the flow resistance is greatly increased and the air permeability is reduced. In addition, the filter material is susceptible to harmful microorganisms and there is a secondary pollution problem.

4 Are there any relevant detection standards for PM2.5 masks? What is the test basis? What are the testing items?

In the field of national masks, we have not yet introduced national standards.

Standard industrial masks are GB 2626-2006 "Respiratory protective equipment self-absorbing filter type particulate respirator", medical masks are GB 19083-2010 "Technical Requirements for Medical Protective Masks", and GB 15979-2002 "Hygienic Standards for Disposable Hygiene Products" And other national standards.
The quality supervision department mainly adopts: GB 2626-2006 "Respiratory protection products self-priming filter type particulate respirator", GB 15979-2002 "Sanitary standard for disposable sanitary products" and GB 18401-2010 "National basic safety technical specification for textile products 》Identification of masks, filtration efficiency, microbiological indicators (total number of bacterial colonies, coliform bacteria, total number of pathogenic pyogenic bacteria and fungal colonies), textile safety technical requirements (formaldehyde content, pH value, and degradable carcinogenic aromatic amine dyes), etc. The project is tested.

5 How can consumers choose according to their own needs?

To evaluate the effectiveness of a mask protection effect, not only from the filter efficiency, but also from the filter efficiency, wear tightness, wear time, pH value and formaldehyde content and other indicators. Consumers are advised to purchase PM2.5 protective masks in pharmacies or large online shopping platforms. The quality is relatively guaranteed.

The test results show that the cotton mask with filter element has better protection effect for PM2.5 particles and is suitable for wearing out normally. See Table 1 for various mask choices.

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