Jessica, I have been using the FemtoTechs since 1991. I have about 40 and have been very happy with their performance--they have a higher cpm. They are currently selling off their used rental units at a very low price to make way for their newer blue tooth enabled units that will be available when the chip shortage resolves.

Thank you for sharing the resource Chris--very informative and a great tool for researchers and techs alike

You make very good points Larainne and one we have been battling for years, especially in California where perceived risk is very low. There is a strong need for additional mapping and data sharing. The CGS interactive map does have a legend that identifies unsurveyed areas but the average citizen wouldn't find it. I agree the word low shouldn't be used. The hazard disclosure here does elaborate low means 6% of homes in a low area are expected to be elevated. In my report I change the wording to lower and add the usual variables such as foundation type which increase risk. The CGS map does miss some areas where risk based on geology is categorized as low but where the growing number of basement homes has increased that risk. To combat that and grow local awareness, I follow the CGS map with my own data that provides more insight into their neighborhood and helps educate realtors. The example below would be a "low" risk area where the number of basement homes is increasing. Red is = >4 and yellow is > 2.7. As you see, this neighborhood should be categorized high risk for homes without a well ventilated foundation. We are noticing a trend to mitigate levels over the WHO recommendation of 2.7. Is anyone else seeing this also?
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I have been including this map in my client reports for several years now. The areas in black are the areas that Ron Churchill of CGS had completed radon potential maps combining geology with available indoor radon data. The natural hazard disclosures in Southern California have finally transitioned away from EPA map to this map. I have been mapping indoor radon data in Los Angeles County for 30 years and when overlayed in GIS it is an amazing fit.

We quote 1 sample every 1,500 sq ft of foundation and place a minimum of 2 monitors per house. We have found most homes will have at least 2 separate foundations or an addition or change in airflow pattern. After the base price there is a set fee for each additional monitor needed. If the home has a finished basement, we test two levels, if it has an elevator extending from the basement we test all levels of the home. We use zillow to preview the home for quoting but if we find something quirky during the site visit we add an extra sample n/c.

I would recommend the home be resampled in a occupied room over the crawl space. The presence of the mechanical equipment and laundry does not make this a suitable test location. Nor do you have a sample over the crawl space foundation.

I would need more context. Is this the garage or converted garage space? In the past year we have found a growing number of incidents of clients expanding into previously unoccupied spaces for working or schooling remotely. In these cases we test the home according to protocol and place an additional test in the space they are working or planning to work in. Many of these samples have come back elevated. This sample is handled in a separate discussion in the report as how to minimize their exposure temporarily to protect their health and what mitigation steps should be taken if they plan to permanently convert the space to occupied space.

Thank you for posting the link, Jane.

Thank you, that was very helpful.

Thank you for all your hard work. Your efforts are appreciated.

I ordered one when they came out so I could evaluate it. I have clients who like to monitor their radon levels in real time after a mitigation system has been installed. I was unable to get the device to sync with three different phones and returned it. The company credited the return okay, but they didn't reimburse me for shipping costs. I won't be recommending it until they work out the kinks. I see they have a booth at the conference so you will get a chance to play with one.