This has to come, from what your place is made of or where it stands, as aritmo mentioned in his bad cleanup situation he found. In LV chances are it is various

This has to come, from what your place is made of or where it stands, as aritmo mentioned in his bad cleanup situation he found. In LV chances are it is various formaldehyde outgassers. The main ones are UFFI = Urea Formaldehyde Foam Insulation and numerous plastics made with phenol and formaldehyde. https://en.wikipedia.org/wiki/Urea-formaldehyde https://en.wikipedia.org/wiki/Urea-formaldehyde UFFI is a prolific outgasser of formaldehyde because of 3 reasons, 1 - a stoichiometric excess of formaldehyde to drive to extinction the remanent urea. 2 - badly employed people/equipment 3 - gradual decomposition of the foam over time. UFFI was touted as a good way to seal and retro insulate older houses via foam injection into hole drilled in residential wall gaps - often in the 1-2" range, but could be more. All worked well, people were told the stink of free formaldehyde was fade over time. This was true, but the time was long and the summer bakeout by sunlight on the walls returned. Many were sensitive to formaldehyde. Government here outlawed this government approved insulation and many people received grants to remove it - a very difficult process. it has largely faded as formaldehyde is volatile and this was years ago. https://www.csmonitor.com/1981/0917/091704.html https://www.csmonitor.com/1981/0917/091704.html Your levels are low, it may be something else in the air So was your place foamed years ago or is this a recent home job by the landlord with industrial foam not intended for houses? Search government web sites. and test web sites. https://www.canadianhomeinspection.com/home-reference-library/attic-roof-space/uffi/#:~:text=UFFI%20should%20be%20removed%20if,it%20a%20less%20effective%20insulator https://www.canadianhomeinspection.com/home-reference-librar....