Almost perfect! Testing with the US-EPA approval equipment, the Edimax Indoor AirBox received a close positive correlation

Taipei, Taiwan 

Along with the air monitoring technologies progressed and the development of IoT applications, today’s air quality sensing products and solutions are becoming more popular and more affordable for people. Comparing to the past, those data output from low-cost (less than USD2000 per pollutant type) air quality sensors is closer to the data outputs from large regulatory monitoring stations of governments. As The US Environmental Protection Agency (EPA) said, “Deciding how to include new technologies into EPA’s monitoring strategy is an ongoing process.” This issue about covering consumer AQI products being testified through a systematic program of standard method is receiving attention from both manufacturers and governments.

To help to improve the industry standard of AQI products, Edimax, the pioneer and expert in sensor-to-the-cloud IoT solutions provider, has recently joined a governmental PM2.5 measurement project in Taiwan. The test result of Edimax’s indoor air quality monitoring product: AI-2002W has stable and consistent quality and its value of correlation is very close to the performance of the federal reference measurement device which is approved by the US EPA.

This measurement service was carried out by Industrial Technology Research Institute (ITRI) of Taiwan and commissioned by Environmental Protection Administration of Executive Yuan, ROC.  The analysis of PM2.5 is based on the methods of Federal Reference Method (FRM) and Federal Equivalent Method (FEM) which are clearly defined and standardized on how to implement compliance monitoring by the US EPA. The equivalent instrument/spectrometer provides high-resolution and real-time aerodynamic measurements of PM2.5 to participate in the test with three Edimax AI-2002W devices. The Field Testing was conducted at the same sampling site for consecutive seven days.
After a side-by-side comparison of Edimax AI-2002W and the FEM/FRM instrument on measuring the same pollutant, AI-2002W’s PM2.5 sensors scored 9.9 of intra-model variability (IMV) that proved the consistency of three units of the same sensor type.  Moreover, for the comparison of the correlation coefficient test, the AI-2002W's data approached nearly perfect to FRM/FEM readings: the slope curve is 1 regardless averaged data every 5 min or 1 hour. And the corresponding correlation coefficient (R2 ) of AI-2002W is 0.97 that also reflected a very high correlation to the results of the US-EPA approved spectrometer.
PM2.5 Sensor Evaluation Summary
  • Manufacturer/Model: Edimax EdiGreen Home (AI-2002W)
  • Pollutants: PM2.5  
  • Measurement Range: 0~1500 μg/m3 , Resolution: 1 μg/m3, Type: Optical
  • Deployment period: Oct. 8-15, 2018

Field Testing Highlights: 
  1. The EdiGreen Home sensors showed good correlations coefficient (Field R2 : 0.96~0.97) with PM2.5 concentration change as monitored by high-end equipment which is a Federal Equivalent Method (FEM) instrument and receives certificates and approvals from US-EPA, UK-MCERTS, CN-CMA, etc. An R2 approaching the value of 1 reflects a near perfect agreement, whereas a value of 0 indicates a complete lack of correlation. 
  2. The EdiGreen Home sensors had good data recovery (93.7% for 5-min average in the field)

Field Testing Result
  • Intra-model variability IMV (%) : 9.9
  • Relative change (%) : - 0.9
  • Data recovery (%) : 93.7
  • Linear Correlation Coefficient 

The government took the lead in supporting to better evaluate the actual performance of the low-cost air quality sensors, which is very important to help to establish a complete verification system for many commercially available air monitoring products on the market. Out of the many benefits, firstly is helping consumers to understand the actual performance of various sensors while purchasing such products. Secondly, a standard measurement also helps manufacturers to evaluate, develop, and invest in the IoT sensor market more effectively. Through the verification of the testing platform, such low-cost and easy-of-use sensors not only are tools to amateur users but also have a high potential of becoming parts of the law enforcement auxiliary devices to quantify air quality in urban cities. All possibilities above must begin with the establishment of the standard measurement by a certified evaluation center.

Edimax has globally deployed more than 3000 air quality monitoring stations with its 24/7 EdiGreen Cloud since 2016. The EdiGreen air quality solution has been endorsed by the governments and academic researchers in Taiwan, Korea, and other ASEAN countries. Edimax will join more side-by-side tests with the FRM/FEM monitoring instrument to support the government measurement project for the regulatory purpose of targeted gases monitoring devices. That will also enhance the progress of the IoT industry for Taiwan and the world.  

About Edimax Technology
Edimax Technology is dedicated to the design, development and manufacture of smart networking solutions for homes and business. With 32 years of dedication and a worldwide footprint, the company provides superior solutions that combine the latest and best-fitting technology with customer needs. 20 branch offices around the world offer direct, real-time services and support to more than 300 partners across 70 countries. With ISO 9000/14000 certification and recognized by Interbrand as one of the top 35 global Taiwanese brands, the company consistently delivers advanced networking solutions and services based on its core values of Quality, Service, Innovation and Integrity (QSII).


SCAQMD, PM2.5, evalution, field test, GRIMM, Edimax, AirBox, AI-2002W