How to detect indoor air quality? There are different results, which is accurate?

How to detect indoor air quality With the public's continuous concern about air pollution, especially indoor air pollution, in recent years, a "new environmental protection product"-a simple air quality detector has also become a hot item.

Half a month ago, Miss Huang updated some furniture for her bedroom. This was a happy thing, but it was messed up by a small "air quality detector": because she was worried about the formaldehyde emission of new furniture, Miss Huang bought several simple air quality detectors for testing, and the results were different. In the end, only by entrusting an authoritative testing department to conduct testing, Miss Huang ate a "reassuring".

Miss Huang's case is not a case. While the simple air quality detector is selling well, its detection accuracy has also been questioned. On the online shopping platform, comments such as "inaccurate measurement data" and "two minutes apart in the same place" can be seen everywhere. Some insiders said that the current household air quality detector is a new product, and there is no complete product standard, and it does not belong to the scope that must be tested and certified by the national technical supervision department. The quality of products is inevitably uneven.

"At present, choosing home products with high environmental protection standards, strengthening ventilation and equipped with air purifiers are the best choices to prevent indoor formaldehyde from exceeding the standard." Guo Wenjing, director of the composite materials room of the Wood Industry Research Institute of China Academy of Forestry, said in an interview with the media.

Consumer: The test results are different, which one is accurate?

How hot is the air quality detector at present?

Enter the keyword "household air detector" on the e-commerce platform, and the products found are dazzling, reaching more than 4,000 pieces. In terms of price, ranging from tens of yuan to thousands of yuan, the monthly sales volume of a hot-selling product with a price less than that of 40 yuan exceeds 25,000 pieces.

In addition, the comprehensive comparison of these products, regardless of the price, are advertised as "professional instruments", "national certification", "ultra-high precision" and "10 year life", and accurate values can be detected within a few minutes.

It is worth noting that some household air detectors not only detect formaldehyde content, but also advertise that they have two-in-one function, and can also detect PM2.5 content, even the "all-in-one" function, including benzene, ammonia, toluene, xylene, TVOC, carbon monoxide, carbon dioxide, etc., which can measure pollutant content.

Moreover, some high-tech household air detectors can effectively eliminate the interference of ethanol and carbon monoxide, thus improving the accuracy of formaldehyde measurement; It can monitor gas, freon gas, ethanol gas and even human oral odor, and also has built-in electronic clock, voice prompt, remote control and other functions.

However, according to industry insiders, the function of household air detector is not so powerful. According to reports, the principle of the detector is mostly the detection principle of electrochemical sensors, which are also sensitive to temperature. Generally speaking, the reading of the sensor will increase with the increase of temperature, and it will not work normally in extreme environment. Therefore, it is only suitable for indoor air purification manufacturers or individuals as a general test in some areas, and the test results are not recognized and cannot be used as an effective legal basis.

On the other hand, the service life of electrochemical sensors is generally one to three years, and it usually takes about two years to replace them, instead of the "ten-year warranty" claimed by some products.

Miss Huang is a typical case. I thought I could get an accurate value from the household air quality detector. Miss Huang bought several detectors online for testing, but she didn't expect to be "recruited".

"Some said, some didn't. Finally, I don't know which one to believe. " After adding new furniture, Miss Huang was in trouble before she could enjoy it.

It turned out that after adding furniture, Miss Huang happened to see a household air quality detector on the Internet, and the price was only 100 yuan, so she bought an air quality detector from the Internet and planned to personally test whether the formaldehyde emission of furniture was qualified.

The test results are surprising. According to this detector, the formaldehyde content in Miss Huang's bedroom exceeded the standard. In order to verify the accuracy of the measurement results, Miss Huang bought several different brands of detectors online. Who would have thought that this time, Miss Huang was even more panicked-the measurement results of the three devices were inconsistent, and some measurement items were still more than 10 times different.

Scholars at home and abroad call for the establishment of supervision system.

In fact, it is not uncommon for the test results to differ by more than 10 times. Professionals from authoritative quality inspection institutions in Guangzhou participated in a group of comparative experiments, and found that the difference between the results measured by household air quality detectors and professional detectors was as high as 17.5 times.

Compared with the professional measurement of authoritative quality inspection institutions in Guangzhou, we bought three detectors with different brands and medium price (500 yuan ~ 1000 yuan) from the e-commerce platform. The formaldehyde content in indoor air was sampled and detected at the same time and place with the above detector, and the experimental results were quite different, which was surprising.

First, the bedroom was tested. The formaldehyde detection result of Guangzhou authoritative quality inspection organization is 0. 12mg/m_, while the data measured by three online shopping detectors are 0.59mg/m_, 0.22mg/m_, 0. 14mg/m_, which is nearly five times higher than that of authoritative organizations.

The difference in test results in the study is even greater. The authoritative quality inspection organization in Guangzhou still measured 0. 12mg/m_, but the measured values of three online shopping detectors reached 1.89mg/m_, 2. 10mg/m_ and 0.39mg/m_, respectively, with the highest difference 17.5.

"The comparative conclusion shows that the test results of the' rapid air quality detector' are inaccurate, sometimes more than 10 times higher than the test results of the testing institutions. Using different brands of' fast air quality detectors', the test results will be very different. " A professional from an authoritative quality inspection agency in Guangzhou said that because it was a comparative test, the above test data were not tested at standard temperature, so the test results of the agency were still on the high side.

It is worth noting that the accuracy of the detector has attracted the attention of scholars abroad.

According to Caixin. Com, 2065438+On July 7th, 2006, AlastairLewis and PeterEdwards, two atmospheric chemists from the National Atmospheric Science Center of York University, England, wrote an article in Nature, questioning the accuracy of cheap air pollution detection devices and calling on researchers and the government to strengthen the inspection of the accuracy of these detectors and issue relevant standards.

In an interview with Caixin, Peter Edwards said that the technologies used in traditional air pollution detection devices have been repeatedly tested by professional institutions before use, and the measurement methods are traceable and the uncertainty is controllable. The only problem with these devices is their high cost. Generally, each device needs 1 10,000 to110,000 USD.

Peter Edwards also said that for small detectors, although the price is low and the idea is accurate, the technology used has not been strictly tested and it is impossible to make accurate measurements in the real atmospheric environment. The test results of cheap equipment vary greatly, and the interference and stability problems make it difficult for these equipment to make truly reliable measurements.

According to industry insiders, consumers don't have to worry about the absolute value of household air detectors. "We should pay attention to our own feelings and improve the air quality in space through appropriate methods. The government and regulatory agencies should also introduce corresponding standards as soon as possible to bring these cheap air quality testing equipment into a unified regulatory system. "