Are Consumer-grade Formaldehyde Detectors Truly Accurate?

Posted on April 9, 2019

    With the growing awareness of indoor air quality, people now pay more attention to the safety and comfort of the indoor environment, especially the air quality after renovation. The demand for air monitoring has increased, and many portable formaldehyde monitors with a low price have appeared on the market. However, as a recent article announced, popular formaldehyde detectors available over the internet have failed quality tests by Shanghai city’s quality watchdog.

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    Recently, the Shanghai Market Supervision Bureau released the testing results for 41 “Formaldehyde detectors”. The detectors being tested were bought from and Tmall, have high quantities sold, and covered almost 20 brands produced in Beijing, Shanghai, Guangzhou, and Shenzhen. Most detectors were priced below 1000rmb and were stated to have “certified accuracy”. The Market Supervision Bureau tested their numerical errors (or deviations) and numerical repeatability, two indices used to assess the accuracy of formaldehyde detectors. According to the Bureau, all sample detectors failed both indexes, indicating that none of the detectors is eligible for accurately testing Formaldehyde concentration.

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    During the test, some of the detectors read zero in all 6 environments that actually contained different levels of formaldehyde. Other detectors showed opposite results, reading higher in environments with low formaldehyde density than in those in high-density environments.


    Experts with the Shanghai Institute of Measurement and Testing Technology say that most detectors at this price range use the diffused sampling method, which can easily be affected by other environmental factors, making it hard to accurately assess the actual concentration. Ding Zhenmin, the deputy director of the Shanghai Institute of Measurement and Testing Technology, also indicates that detectors without regular calibration are unable to maintain accurate readings. Unfortunately, few if any of these online stores provide calibration for low-cost detectors.   


How should Formaldehyde concentrations be tested?


GB 50325-2010 stipulates: 


    The method for detecting formaldehyde in indoor air of civil construction projects shall comply with the provisions of the current national standard GB/T 18204.26 “Methods for testing formaldehyde in public area” for the spectrophotometric method.

spectrophotometric method

    This method requires trained professionals to collect air samples which are then measured in a lab. Formaldehyde testing is essential for post construction, so owners know when to move in with healthy air quality. Therefore, to truly know what your formaldehyde levels are, you need professionals to assist.  PureLiving offers testing packages for both commercial and residential that includes tests for a variety of particles, including formaldehyde, that are major concerns for people. By knowing the root problem, solutions can take place to improve your air quality.