Xinhua carried an article reporting on the use of PM 2.5 detectors. [Editor’s note: PM 2.5 is particulate matter with a diameter of 2.5 micrometers or less. Referred to as "fine" particulates, they are believed to pose the largest health risk.] According to an expert, none of the PM 2.5 detectors for home use that test air quality and are sold at China’s markets are reliable. The article stated that there are several hundred types of detectors sold on the market; the cost ranges from 100 yuan or less to several thousand. Both their accuracy and their reliability, however, are questionable. In a test discussed in the article, two different brands of detector gave two different results. The article also quoted the expert as saying that the state has not provided standard specifications for the air quality detectors in general; nor has the industry.
Source: Xinhua, July 25, 2016