Air formaldehyde detection products
At present, there are more and more products and institutions on indoor air testing in the market. Consumers are often confused when faced with these products.
Experts said: “At present, there are nearly 300,000 employees engaged in indoor environmental testing and purification and treatment, and more than 200 companies that produce indoor environmental purification and treatment products (such as activated carbon, photocatalyst, and odor removal products such as formaldehyde) are engaged in purification and management. There are more than 3,000 service companies, and the production value in 2012 has reached more than 60 billion yuan."
Among these, formaldehyde detection has become an important one. According to industry experts, at present, the national standard for the detection of formaldehyde in the air is "Test Method for Formaldehyde in Air in Public Places" (GB/T18204.26-2000). Currently, the common test methods in the industry include phenol reagent spectrophotometry. Acetylacetone spectrophotometry and gas chromatography three. These three methods usually collect a certain amount of air samples, react with formaldehyde and other substances in the air, analyze the color and spectrum of the reactants, and calculate the formaldehyde content. At present, the market's testing institutions and testing products also come from national standards.
Air control effect without standard
Testing agencies and testing products need to be certified by the measurement unit. According to Song Guangsheng, director of the National Indoor Environment and Indoor Environmental Protection Product Quality Supervision and Inspection Center, a professional testing organization needs to have the China Metrology Accreditation (CMA) mark, which is the most basic necessary qualification for indoor air quality testing organizations. At the same time, it must also have a national laboratory certification, that is, with the "CNAL" logo, consumers can choose to regulate the company based on these two certifications. Professional testing tools also need to be "CMC" certified, that is, "the People's Republic of China manufacturing measuring instruments license" logo, is the English abbreviation for "China Metrology Certification".
However, at present, there is no relevant standard for the effect of indoor air treatment in the country, and there is only one method for measuring the effect (“Method for Determination of Purification Effect of Indoor Air Purification Products†(QB/T 2761-2006)). In the view of the industry, as long as the governance is carried out, the result is within the standard limit, which means that the product or technology is qualified.
Experts remind that when selecting testing organizations and testing products, we must choose qualified companies and products to get the minimum guarantee. In addition, the pollution sources and physical environment in each family are different, and they must be selected according to the actual situation.
"Formaldehyde self-test" product price difference
Xiao Bian found that, in addition to professional testing agencies, the market also has "home formaldehyde self-test equipment," prices ranging from tens of dollars to several hundred dollars, compared with the detection company's on-site service is much cheaper.
In an online shopping mall, "home formaldehyde detection" was used as a keyword to search for more than 200 items. The most expensive of them is nearly 2,000 yuan, and the lowest price is less than 10 yuan.
According to the comparison, these detection products are roughly divided into two types according to the working principle: one instrument is equipped with a liquid crystal display, which can immediately display the formaldehyde content of air in the space; the other is a detection box, which is given by the color change of the reagent liquid. The color card is compared to determine the content of formaldehyde in the air.
In the product introduction, these two types of products can detect benzene, TVOC, particulate matter and many other substances in addition to the formaldehyde content. For the test results, no business description can be used as a legal basis. For example, a paragraph of "indoor air formaldehyde, benzene detection kit 4 boxes" of the product in the note: "This product is only as a semi-quantitative detection, can not be used as a legal basis."
Wide range of formaldehyde sources, difficult to exceed the standard
According to industry insiders, there are currently two standards, namely the "Code for the Control of Indoor Environmental Pollution in Civil Construction Projects" (GB50325-2001) and the "Indoor Air Quality Index" (GB T18883-2002).
The former is a national mandatory standard. It mainly measures the pollution concentration of various decoration materials and materials such as adhesives and other materials that may be used in construction and installation, and the pollution of the chemical after decoration. The latter is the recommended standard for air. 19 physical and chemical indicators of quality were measured. For the formaldehyde content in the air, the former requires that the free formaldehyde per cubic meter should not exceed 0.08 milligrams in the Class I civil construction project; the latter requires that the free formaldehyde per cubic meter should not exceed 0.10 milligrams.
According to experts, "Code for Control of Indoor Environmental Pollution in Civil Building Projects" is an important criterion for acceptance by the decoration company. Because decoration projects often do not include furniture, it is not difficult to achieve standards.
However, the sources of formaldehyde are relatively wide. After the furniture enters the market, furniture, curtains, carpets, and cabinets may generate formaldehyde, and multiple sources of pollution will superimpose, causing excessive formaldehyde. At present, there are no scientific guidelines for how much furniture is placed in space. If this situation arises, it is difficult to find out which business is responsible and it needs comprehensive management to improve it.
Sensor determines detection accuracy
For the fast, direct-reading formaldehyde testing instruments and detection boxes and testing reagents sold on the market, Song Guangsheng said that the core of these instruments is the built-in sensors. Their working principle is that their built-in electro-optical sensors can react with formaldehyde in the air and can directly display the formaldehyde content on the LCD screen; and the color card comparison method also produces a color by reacting formaldehyde with the reagents. Compounds are compared by the given color card.
For the detection effect of such products, experts said: "The sensitivity of the sensor determines the accuracy of the test results. If the sensor is of poor quality, it is insensitive and results in errors. The reagents are compared with the color card according to the color change of the liquid. Out of the range of formaldehyde content, the exact value can not be measured. And the detection of specific formaldehyde content and humidity, temperature, pressure are all related to these conditions, the results can only be used as a reference."
The test results of such products cannot be used as a basis for governance or legal basis. If you want to obtain professional and accurate results, you should also have a qualified testing organization to carry out tests.
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