[recycled sixtie]

Your wife has a legitimate concern about air quality. About 5 years ago we had mould in our basement caused by using the humidifier in the basement too much especially in the winter. Also the panelling was basically just fibreboard with some insulation behind it which had fallen down over time. I removed all the old panelling(I used an air breather filter mask) and treated the walls with a special mould spray and removed all the mould. Apparently this job is supposed to be done by professionals but I must have done a good job because there is no more mould.

To get back to your question my wife says that she thinks that u can get an air quality test kit which would be a lot cheaper than getting somebody in to professionally test it. Do what u have to do to get clean air in your house. Other risks are: you may have radon(?) gas, asbestos tiles, mould, dust etc. I find that we feel better in the summer because the furnace is not running(forced air gas furnace). In the winter the furnace blows who knows what(we change the furnace filter regularly). Is the prof. air quality tester a scam? Definitely not.
But perhaps you can do it yourself. There is nothing worse than allergy problems/breathing problems.