Anybody using a fine mesh "bag" over PurpleAir monitors to keep out bugs/debris?

Per the title, has anybody used a fine mesh screen to keep out bugs and debris from the sensors? I wouldn’t want to interrupt the airflow, but I have also found that many of my sensors are getting bugs and other stuff in them, requiring frequent maintenance and sensor replacement. It dawned on me during a recent maintenance outing that a bag made of a fine metal or plastic mesh could potentially do wonders for keeping the device clean. That said, I wouldn’t want to meaningfully disrupt air flow (or filter out air pollution particles) to the device (causing lag or otherwise decreasing accuracy). Has anybody done any testing of something like this? Here’s the mesh I’m considering:

2 Packs 304 Stainless Steel Woven Wire 120 Mesh Fine Screen Mesh Steel Woven Mesh for Filter Mesh, Filtration Cloth, 11.8 x 39.3 Inch

Thanks for any input!

Always monitoring,

I queried Adrain of Purple Air about doing this as I had a bug problem too. He advised not to cover the opening with anything.

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Good to know. Thanks for sharing that advice!

Perhaps, a insect repellent might do the trick, which could be applied sporadically on the outer casing and reapplied as and when needed.

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Unless the repellent interferes with the data, in which case ignore my previous response.

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My sensors have always a lot of problems with small animals… they are too pry
often some comparisons between different sensors are invalidated because one of the sensors has started to monitor insect works rather than monitoring the air.

So all my sensors have a small protective net (a plastic mosquito net). PA-II also has one.



How did you attach the screen to the bottom of the device? I want to do this to my purple as it will be in a remote location and there be no one to clean out the bugs.

The monitor has a VOC sensor in it. Not sure how that might be affected by bug spray, but I’d imagine there are some VOC’s in bug spray.

The bugs I often see are even smaller than those holes. Little tiny tiny bugs. Smaller than mosquitos.

Anyone have any good ideas on how to attach the screen to the bottom of the purple?

I understand the desire to do this, but seems it would interfere with free flow of particulate matter (impacting ability to get accurate read).


sorry if i didn’t answer earlier, i had some health problems in my family.

if the piece of mosquito net has no folds it is simple.

  • I placed the sensor upside down stably (I used the packaging sponge).
  • I cut the mosquito net in a circle with the same diameter and then held it steady with a negligible weight but sufficient for the purpose (a metal pencil sharpener)
  • I dropped small drops of quick glue (attack or similar) as large as a single hole in the mosquito net.
  • My mosquito net was not perfectly straight so I had to use more fixing points because it always had some ripples that kept it up. I used about 12/14 very small glue points, but 8 would be enough.

I made the hole in the net to pass the power supply after using a small pointed scissor.

This solution does not solve the problem for any type of insect, but for 95% of the cases it does. If the sensor is on the roof or far from the garden, plants, trees, the chances of being visited are significantly reduced.
For me this solution was optimal, it is easily removable, the glue residues come off quickly with a cutter and then I will cut a new piece of mosquito net after the next maintenance.
I have several sensors, without this solution I was forced to do maintenance continuously or have sensors gone crazy and data unusable

For comparison I have installed other sensors of other brands. For some I would have had to use too invasive a solution and they forced me to put them in a box. PA, on the other hand, is ideal from this point of view.
For example, to not ruin this sensor and make it work optimally anyway, I had to insert it for 3/4 in a box with the same solution in a lot of holes


Thanks for posting an update. I ended up putting a screen door patch over the bottom and used a hose clamp to hold the screen in place. The screen door screen patch was baraly big enough to cover the bottom and go up the sides enough to be held in place with the hose clamp. Should work well enough to keep wasps and bees out of it.

My Purple is located at my rental hose in another state 8 hrs away. So pretty hard to get to it if bugs decided to make it home.