Hi @abth88 !
What you’re seeing is probably due to cross sensitvities. The formaldehyde sensor is sensitive and accurate, but like all gas sensors it’s not 100% selective. Frying food can release other aldehydes such as acetaldehyde, and sprays or deodorants often contain isopropanol or ethanol. These substances are chemically similar enough that the sensor can respond to them, which explains the short spikes alongside TVOCs.
The key is to focus on the long-term baseline. Brief peaks during cooking or spraying are expected and not a sign of harmful formaldehyde levels. Only if readings stay elevated for hours or days without an obvious source should they be taken as a more serious indication.
Best regards
Merlin