Yup I got a pm2.5 & AQI monitor a couple years ago and was so excited to have a fireplace in my new house, but trying it with the monitor showed me I really shouldn't. I am considering an enclosed fireplace to still be able to use it. I am now wondering if just emitting it into the air (out of the chimney) is acceptable.

EDIT: also it's been shocking to check on it while cooking, our vent hood is mediocre to bad so we end up keeping a door open most of the time we are cooking