Organisation that will identify house smell?

I noticed someone else on here asking for help re a smell. We have a problem with what I thought was a decorating smell in front part of the house. However it has gone on rather long. Tried the paper towel and foil test but neither helper nor I could pin it down. I think, for a fee, there is an organisation who will identify a smell source. I got a new microwave the other day and thought I smelled something similar in the packaging but it didn't linger. So perhaps a glue or insulation? With foil test walls and carpet checked so really at a loss. Does anyone know about the organisation or others who help?

I know paint and wallpaper smell lingers for years, glues used in building contain formaldehyde and the stink it never goes, the smell in plastic carpet never leaves. So betting its your renos that are causing your smell.

what ventilation do you have?
a simple fix is to rig up a fan to blow into the house, that tends to push the smell out.

one of the issues these days is "low voc" products. the amount of voc is the same, it just comes out at a lower rate. if you have a sensitive nose you might be able to notice it and unfortunately it will continue for years.
good household ventilation is your friend.

otherwise frankly your nose is the best instrument for the job. tho i would suggest putting some smoke, fog, steam?, into the air so you can see where the air is moving. if you smell it in one spot and see where the air is flowing from, you know where to smell next.

Is it a new build, Hessian? - Also, can you describe the smell, does it remind you of anything in particular?

I thought it was a decorating sort of smell and so does someone else. I ventilate a lot and it goes but builds up if the two rooms are shut. The whole house had new carpet (cheap I suspect) and a redecorate to sell. It had a clear meths test. I didnt notice it so much then at the end of summer. I also dont think it is as bad as it has been at its height but maybe I am used to it.
I know it is expensive to get outside help. Thirty years ago I had someone from Auckland to check smell in a room where new Cavalier Bremworth carpet installed. It was the carpet and Fair Go were prepared to back me after a rude letter from CEO but my husband refused to follow through. It was improperly cured carpet glue. This isnt as nasty.
I am just wondering if it is VOCs or something to do with insulation. However whole house was redecorated and the smell is only at the east facing front. Long forgotten firm name which unlikely to exist anyway now.