As one of the leading suppliers of both consumer and professional electronic radon detection equipment, Ecosense has made a strong commitment to have its products available for independent third party testing. The results to date are persuasive and have surprised radon professionals.
As is well known, rigorous laboratory-based determinations of radon concentration and the extension of the conclusions from such work to real world measurements are not a simple matter. For instance, there are known effects of ambient temperature and humidity, low count rates leading to issues of signal-to-noise ratio, and there can be dramatic day-to-day variations of radon level in buildings depending upon, among other factors, weather, ventilation, and air circulation. Precision can suffer even more so than accuracy.
Herein, we summarize the results of radon chamber testing with Ecosense products to date: 1) A study by the University of Michigan. 2) A study by the Kansas State University Radon Chamber. 3) A study by Gimpo University in the Republic of Korea.
Ecosense’s Radon Detection Products
Figure 1 shows Ecosense’s portfolio of continuous radon monitoring solutions, the RadonEye and RadonEye Pro.
Ecosense’s RadonEye is a consumer-focused product. It features Bluetooth (BLE) connectivity with smartphones, and is compatible with either iOS or Android platforms. Every ten minutes, the RadonEye updates its OLED display with the rolling one-hour average of its last six every-ten-minute measurements. Averages over longer periods of time (daily and monthly) also scroll continuously across the bottom of the OLED display. Via the smartphone app, a graphical visualization of all accumulated data may also be displayed.
Ecosense’s RadonEye Pro is a professional grade product. It is designed for use by home inspectors and radon professionals. This product features both BLE and Wi-Fi connectivity. As with the consumer product, BLE is used for set-up, registration, device control, and for data collection via the smartphone app. After set-up, data is posted via Wi-Fi to the Ecosense cloud, which may then be accessed from either one’s desktop or mobile devices. In general, we find professional inspections are most commonly scheduled for either 48 or 72 hours; however, the RadonEye Pro can be set for timed inspections of any length. Once a timed inspection is set, an embedded accelerometer is able to tell whether the results have become invalid due to any movement of the device. The software provided allows for generating inspection reports in a convenient .pdf file format. Alternatively, a .csv (“comma separated values”) file can be directly opened into an Excel spreadsheet which may be integrated into an inspector’s own reporting templates.
The RadonEye Pro is National Radon Proficiency Program (NRPP) listed (in the USA) and C-NRPP listed (in Canada). Calibration may be performed through support relationships Ecosense has in place with Bowser-Morner, Inc. (USA: Dayton, OH) and the Radiation Safety Institute of Canada (North York, Ontario). Annual calibration is required.
One manner in which Ecosense products are complimentary is that, in the interest of peace of mind, we suggest the consumer product can be a leave-behind after mitigation work is performed by radon professionals.
Both the RadonEye and the RadonEye Pro may be purchased through the Ecosense website: http://ecosense.io The RadonEye may also be purchased on Amazon.
The Sensor Used in Ecosense’s Products
At the heart of both the RadonEye and RadonEye Pro products is a unique radon sensor technology, a pulsed ion chamber whose output is processed by patented ultrasensitive detection circuitry and algorithms (U.S. Patent #10,132,936). Ecosense’s radon detection technology provides 30 count per hour (30 CPH) sensitivity, the highest in the industry. This technology allows both the consumer and professional products to provide an accurate reading every 10 minutes.
The Ecosense radon sensor is so uniquely fast, that it provides an option for the radon-based duty cycle control of Heat Recovery Ventilators (HRVs), an emerging option for, in certain circumstances, low-cost and minimally invasive home radon mitigation projects.
Third Party Validation Studies
- University of Michigan
In 2019, a study was performed by the Department of Nuclear Engineering and Radiological Sciences at the University of Michigan (Ann Arbor, MI) in which the RadonEye was compared to the AlphaGuard professional radon monitor from Saphymo, GmbH (Frankfurt am Main, Germany). [Ref. 1] The AlphaGuard was selected from other professional-grade monitors to be the “gold standard” based upon its highest manufacturer-reported accuracy. Per the researchers, it was then priced at ~$10,000.
In this case, the radon chamber was an underground room that proved to maintain a remarkably constant radon concentration. With the addition of radon sources over and above the natural high background, levels characterized as 1,100-1,500 Bq/m3 (29.7-40.5 pCi/L) were thus studied. Radon levels were monitored by each of the following professional grade radon monitors: the Pylon AB-5 from Pylon Electronics, Inc. (Ottawa, Canada), the Sun Nuclear Model 1027s and Model 1030 from Sun Nuclear Corp. (Melbourne, FL), the Durridge Rad7 from Durridge, Inc. (Billerica, MA), and the Femto-Tech CRM-510 from Femto-Tech, Inc. (Carlisle, OH).
Figure 2 shows that in the University of Michigan study, the RadonEye is essentially as accurate as the AlphaGuard. Two quotes are of particular interest: 1) “The… RadonEye was identified as a likely candidate for other experiments due to its strong performance, low price tag, ability to record measurements over set time intervals, and the ability to extract data using only a smartphone.” 2) “The ease of use of the… RadonEye is another feature that makes it desirable for use. It is merely plugged into an outlet and all the data can be extracted with a cell phone using their app.”
- Kansas State University Radon Chamber
Kansas State University personnel performed a 72-hour study at the Kansas State University Radon Chamber (Manhattan, KS) with settings at 10-20 pCi/L (Day 1), 55-65 pCi/L (Day 2), and 25-35 pCi/L (Day 3), as monitored by a Pylon AB-5. [Ref. 2] Three sets of five each of the following consumer devices were tested: RadonEye, Airthings Wave, and Airthings Wave Plus.
Significant differences were found between the values reported by the units tested. The data taken show a standard deviation of 1.15 for RadonEye, vs. 1.81 for Wave+, and 2.61 for Wave in Individual Relative Error (IRE) versus the average 32.6 pCi/L radon concentration of the chamber as measured by the Pylon AB-5. Expressed in a simpler way, approximately 1/3 of the time, both Airthings Wave devices will produce a value outside the variation of the RadonEye. Figure 3 shows an example of this testing comparing the IRE of the RadonEye and the Wave versus the Pylon AB-5.
Figure 4 provides an example of a systematic difference in the pCi/L hourly data provided by a representative subset of the devices studied. Given that the RadonEye provides a new 1-hour average every ten minutes and the Wave devices produce a new 24-hour average every hour, it is understandable that there is a lag of several hours (in Figure 4 clearly a day) in fully responding to changes in radon level. If one desires to quickly survey a number of locations within a home to decide upon where to set-up long-term testing, such a lag does present an issue. In a laboratory environment where the level of radon is kept constant, such lag times may be irrelevant; however, in a practical environment where radon levels often fluctuate wildly, RadonEye products from Ecosense likely provide more accurate initial measurements.
Decision making on radon mitigation projects should be made on the basis of long term multi-seasonal testing; however, there is value in short term data. If trends in short-term data may be visualized on one’s smartphone, it is increasingly likely a consumer may be able to correlate high and low values to at least indoor/outdoor temperature differential and ventilation behavior. Depending upon the interest a consumer takes, it is entirely possible to get into the habit of turning on ventilation or cracking open a window or two when readings creep higher.
- Gimpo University
In 2016, a study was performed at Gimpo University (Gimpodaehak-ro, Republic of Korea) in which the RadonEye was compared to the Rad7. [Ref. 3] The radon chamber used was a small outdoor building of ~10 m3 volume designed to simulate single story residential construction methods (including a peaked roof and a conventional door and window). The negative pressure effects of diurnal temperature changes produced a draw on an externally ducted solid source producing radon by radioactive decay.
Over a period of ~500 hours, radon concentrations varied over the range of 10-500 Bq/m3 (0.27-13.5 pCi/L). Figure 5 shows that RadonEye was able to essentially read identically to the Rad7 (then, per the researchers, priced at ~$8,000). The area circled within Figure 5 corresponds to rising and falling radon levels across the U.S. and Canadian recommended thresholds for homeowners to make remediation decisions.
- Consumer Reports
While the widely trusted Consumer Reports organization (Yonkers, NY), a non-profit, has produced articles comparing radon detection products in the past, these predate the general consumer availability of continuous electronic monitors. Their reporting thus focuses on passive detection approaches such as plastic chip track detectors and carbon absorption cartridges, both of which must be sent away for laboratory analysis after exposure. Ecosense is lobbying for an update study to include electronic monitors.
Third party cross-comparative studies have confirmed that RadonEye products are as accurate as professional grade radon test equipment priced many times higher. Nothing is sacrificed if one opts for more economical radon measurement solutions from Ecosense.
Importantly, due to the 30 CPH capability of Ecosense products resulting in 10-minute updates, both consumers and professionals are able to use the product as a “sniffer.” We suggest that if left for an hour in every position of interest, hot spots can be identified in which to set up either timed inspections or continuous monitoring. With Ecosense products, and the data visualizations our software makes available to coupled smartphone devices, one can not only perform the most accurate test, but, with minimal additional time invested, one can determine the best place to test. And, if anything concerning is found, remember to call in your trusted radon professional!
- M. Carmona and K. Kearfot, Intercomparison of Commercially Available Active Radon Measurement Devices in a Discovered Radon Chamber,” Health Physics, 116 (6), pp 852-861, 2019
- B. Snead and B. Hanson, “Kansas State Radon Chamber Ecosense Consumer Device Comparison,” unpublished private communication (available upon request from Ecosense)
- Kyungbuk Park, “Comparison of RadonEye and Rad7,” Gimpo University, unpublished private communication (available upon request from Ecosense)
- Photographs of the RadonEye and RadonEye Pro
- University of Michigan Comparison of Ecosense’s RadonEye and Saphymo’s AlphaGuard
- University of Kansas Comparison of Hourly Trends
- University of Kansas Comparison of Response to Changes in Radon Concentration
- Gimpo University Comparison of Ecosense’s RadonEye and Durridge’s Rad7