Ozone measurement for n95 decontamination


I am working on an urgent project to develop decontamination equipment for n95 respirator/masks with colleagues at Stanford University, Harvard, MIT and elsewhere. We are testing using ultraviolet light germicidal lamps for this procedure which can also produce significant amounts of ozone. We need to measure ozone emission from these devices and are hoping you could supply us with some of your mq131 devices as soon as possible. (Or any other suitable devices for measuring ozone.)

We are trying to address an urgent need for decontamination equipment both in the US and other first world countries but especially in limited resource settings where low-cost DIY approaches may be the only option available. Needless to say, time is of the essence for this initiative.

Please contact me as soon as possible by email or by phone to discuss availability of these devices.


Dr. Thomas Baer
Stanford University

@tmbaer Dr. Baer,
I’m not a NCD employee, but I have a few thoughts.

“Hobby” Grade Ozone sensors are usually not very accurate and require a comprehensive calibration.
If your UV lights are indeed Germicidal, they should be coated for the (UV-C) wavelength.
Thus the UV-C light cant produce any Ozone.

Have you considered measuring the wavelength inside the proposed decon equipment to confirm 254nm light is produced and that no 185nm is being emitted?

That’s not a direct measurement of Ozone, but likely a much more accurate method without Lab Grade equipment for every unit you deploy.

A quick search revealed a cheap UV sensor that has a compatible output for confirming UV-C (@ 254nm):

Very interesting project.
Please let me know if I could help in any way.