Question about this Co2 meter - I have one in my preconditioning/plenum room that I’m dumping fresh air directly from outside with an 8” can fan. I have a “dust shroom” foam filter that the fresh air passes through to keep the bugs and dust out. I clean this reusable filter regularly.
Usually this setup can bring the PPMs down to 370-400 range pretty easily. Other times it’s a struggle to keep the PPM’s under 500 and this causes the exhaust fan in my fruiting room to run way longer than it should - drying out my shiitake blocks. I particularly notice this ppm spiking issue in the morning - and in the evening hours. Midday it has no problems maintaining 370-400ppm in said preconditioning room.
My question is can increased pollen production from the plant life outside affect the ppm reading? I’m located in NW Pennsylvania and over the last week goldenrod and ragweed pollen is making everyone’s allergies go crazy. Due to the high PPM’s in the plenum I’ve been struggling to balance the c02 in my grow. Does anyone have an idea of what could be making this happen? Here in North Western PA we’ve been having very cool temperatures in the morning  and warmer afternoons as fall is starting to kick in. This is making me crazy please help!