Existing particle counters typically cost thousands of dollars, generally aren’t designed for stockpiling or in-respirator wear, and have no manufacturing plan suited to a crisis ramp-up.
The cheapest ready-to-go option for DIY work today is probably the Temtop P600, which I see as $70. While I haven’t tried it, it’s a stripped-down version of the Temtop M2000 which is what I bought several years ago to use for DIY experiments.
Professional grade ones are better in various ways, but the big one is that they are calibrated. The cool thing is, for many kinds of experiments you don’t actually need that! You just need some number that is (at least within a known concentration) linearly proportional to pm2.5, which an uncalibrated meter can do. For example, if you’re trying to see how quickly something can clear smoke from a room you don’t need to generate a target amount of smoke or know exactly how much smoke you’ve generated: you can just measure the half life. This gives you relative efficacy directly, or CADR if you have a sealed room of known volume.
If you want to make something cheaper, you can get a PMS5003, which I see as $21, and connect it to a cheap SoC (~$10) or to an Android phone (adapters in the $15 range). At scale I think you could get this down below $15: a PMS5003 or clone at high volume would be ~$7, the phone adapter would be under $1 at this scale, then a box, assembly, and some QC.
But all this is for in-room measurement, good enough for measuring rooms. Measuring non-valved respirators is way harder, because you need to get the sensor inside the mask. State of the art for quantitative fit testing involves poking a hole in a mask, which means you can’t do it on an ongoing basis. I don’t know if wireless is practical with current tech: getting a particle counter sufficiently miniaturized seems super hard. Building respirators with a test port could also work? (For a valved respirator you can measure how clean the air coming out of the valve is.)
The cheapest ready-to-go option for DIY work today is probably the Temtop P600, which I see as $70. While I haven’t tried it, it’s a stripped-down version of the Temtop M2000 which is what I bought several years ago to use for DIY experiments.
Professional grade ones are better in various ways, but the big one is that they are calibrated. The cool thing is, for many kinds of experiments you don’t actually need that! You just need some number that is (at least within a known concentration) linearly proportional to pm2.5, which an uncalibrated meter can do. For example, if you’re trying to see how quickly something can clear smoke from a room you don’t need to generate a target amount of smoke or know exactly how much smoke you’ve generated: you can just measure the half life. This gives you relative efficacy directly, or CADR if you have a sealed room of known volume.
If you want to make something cheaper, you can get a PMS5003, which I see as $21, and connect it to a cheap SoC (~$10) or to an Android phone (adapters in the $15 range). At scale I think you could get this down below $15: a PMS5003 or clone at high volume would be ~$7, the phone adapter would be under $1 at this scale, then a box, assembly, and some QC.
But all this is for in-room measurement, good enough for measuring rooms. Measuring non-valved respirators is way harder, because you need to get the sensor inside the mask. State of the art for quantitative fit testing involves poking a hole in a mask, which means you can’t do it on an ongoing basis. I don’t know if wireless is practical with current tech: getting a particle counter sufficiently miniaturized seems super hard. Building respirators with a test port could also work? (For a valved respirator you can measure how clean the air coming out of the valve is.)