"Chemical" smell inside new A3

My car's 3 weeks old and I've (well, my girlfriend) just noticed in the last few days that there's a bit of a chemical, slightly acrid smell in the car sometimes. She first noticed it when I left her in the car to nip into Tesco for 10 minutes, engine off. Then again today I noticed it when she sat in the car for a moment while I nipped in to get a microfibre to remove some bird poo... she floated the idea that it seems to happen when she has the RNSe on without the engine, but that seemed far fetched.

I stopped noticing it after driving for a moment, but I'm not sure whether that's due to getting used to the smell, it being pumped out/filtered once the aircon starts working, or it going away. There's nothing in the car which has spilled as far as I'm aware - I had a few bottles of wax, polish etc in the boot, but they all look fine. The car is running fine, I can't see any problems, leaks etc under the bonnet.

I think it might just be that I've been cleaning the car more and had just used AutoGlym Car Glass Polish, so some polish or something may have gotten inside, or perhaps just the sun on new interior causing a smell, but I wanted to check whether there's anything more sinister to worry about before I spend 5 hours straight in the car over easter. Plus I'm paranoid

No warning lights, still drives perfectly and the engine is running fine as far as my fairly limited experience of it goes, so I wouldn't have thought it was that - although if it's potentially linked to things such as coil pack or boost, that's a concern.

tbh I'm less bothered about potential failures - the car is under a month old so very much under warranty. My concern is more about whether the smell means anything is leaking into the cabin and potentially a health hazard.

Thanks for the advice guys - I'll keep an eye on it for a few days and see what happens. I've not noticed it in the last couple of days, so it might have been a bit of adhesive doing strange things in the nice weather or something.