Public Lab Research note

This is an attempt to replicate an activity.

Field Test of DIY formaldehyde testing and remediation kit

by nshapiro | May 06, 2015 14:19 06 May 14:19 | #11791 | #11791

As part of the Where We Breathe project of Public Lab we have been developing an inexpensive means of formaldehyde monitoring and an inexpensive living air filter system.

An overview of the project and the links to the various research notes can be found here.

Our goal for this outing was to field test both our formaldehyde monitoring and mitigation devices.


We chose to conduct our field test in a former FEMA mobile home in Picayune Mississippi, in the home of a couple that has been enduring high levels of formaldehyde for since Hurricane Katrina destroyed their home nearly a decade ago. I tested this trailer for formaldehyde in 2011 (news story here) and found a level of 105.69 ppb-- ATSDR states that non-cancerous negative health impacts could begin at 8 ppb.

On Friday April 10th at around 3pm Public Lab Organizer Dan Beavers (a local of Picayune) and I monitored the indoor formaldehyde levels in the above-mentioned mobile home. We tested with two colorimetric techniques, one using the RKI FP-30 photoelectric photometry method, and one using the DIY formaldehyde testing technique, which is a length of stain test. Both tests were placed at equal elevations in the room (>2 feet <4 feet) at least three feet apart so as not to cross contaminate. The front door was open approximately 8 inches when we arrived. Previous tests had taken place with the house sealed.

Humidity: 63% AC Duty Cycle: 40%


Temperature: 75 F


Reading on RKI : 25 ppb


Reading on DIY Kit: 23 ppb at 24 degrees C (rounding up from 23.98) the final reading with temperature correction is 20.24 ppb (we are still working on our photo card)


The two tests were withing 5 ppb of each other, with the DIY test reporting slightly lower.


At the owners request we originally placed the plant filter device on the TV in the corner of the room, after completing the pre-tests.


Due to lack of sunlight and a resulting decline in plant health, the owners moved the plant to the window behind their kitchen sink. IMG_6165.JPG

The kitchen and living room (where the original tests were conducted) are in one continuous space without impediments to air flow.

On April 15th Dan Beavers returned to the residence to conduct an efficacy sample, a little over a month after instillation. Similar to the first test, the front door was open 8-10 inches.

Humidity: un-assessed. 90% is our contraindication, which is uncomfortable for indoor conditions and unlikely that we reached that level.
Temperature: 78 F


The kitchen and living room (where the original tests were conducted) are in one continuous space without impediments to air flow.

Reading on DIY kit: 15 ppb visual read out, with a temperature corrected final reading of 12 ppb. IMG_6167.JPG

While this field test does indicate a 40% reduction in formaldehyde levels after instillation of the plant air filter. This is by no means conclusive. We will need a much larger sample size in order to make more definitive conclusions. The testing method itself was previously validated in a peer review paper (here-pay wall), so it is unsurprising that the DIY technique is within 5ppb of the $1,000 device.

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@danbeavers do you know the duty cycle of the AC when you did the follow up testing?

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I did not think about measuring the AC duty cycle. I think the most influential observation was the front door being open 8 to 10 inches. By the way, the plant was not moved over the kitchen sink. It is across the room from the kitchen. Facing the kitchen from the living room it is on the right side of the trailer.

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Hi Dan and Nick - is there a complete setup available for photography and testing in the NOLA area? I'll be in town next week working on documentation for the project, and was hoping not to bring my whole setup down if possible.

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Warren: I don't have the complete setup here that Nick has been using. I have 1 unused and one used tube and the rest of the equipment shown in my pictures less the flow meter that was mailed back to Nick. Of course my pump is not the model Nick is using.

My schedule is clear next week.

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