Maybe it's sand from Sahara @Barski

I have travelled on holiday to Northern Norway to Andøya.
There I met people who have talked about the beautiful sunsets that have been there in the last couple of evenings.
They have read and heard that there should be sand from the Sahara that has been transported with a southern wind all the way up here.
Then probably the explanation you have suggested is the reason for the amazing colours that are now.
They are the yellow and partly brownish colours that may be due to this sand from the Sahara
I think the beautiful red tones, which are the natural colours, are those made of the typical atmosphere.
So I think your explanation is the right one for these unique colours.
Many thanks @Barski