Maybe you could vent the crawlspace using mechanical ventilation.
Regarding the levels of formaldehyde in your home, an Indoor Environmental Consultant should be able to take samples and have them sent to a lab.
- The only problem is that the results will only reflect specifically what you are testing for.
- What if the problem is something other than formaldehyde...did you test for that...see my point?
Rather than spend money on the tests, my advice would be to get to the source of the problem, which sounds like it is water-related...and fix it. That's because, even if you find high formaldehyde levels, what are you ultimately going to do about it?
- VOCs (volatile organic compounds) are greatly increased by high humidity.
- If you can decrease the humidity, you may be able to eliminate your issue altogether.
That's why I suggested venting the crawlspace with some form of mechanical ventilation.
Good luck, and I hope that helps!
For more information:
Read "Do I need an indoor air quality test? How much will it cost?" a Q&A answered by Evan Little.