see is that nobody really knows a whole lot about it, but that doesn't mean don't be concerned. Most experts were saying "fix it" if it's above 0, as any breathing of radon is bad. The 2-4 was essentially chosen since most people would reject "anything above 0".

But the first step if you are around 4 is to do a long term test. Radon is cyclical and just because you were 4 on a 24-hr test doesn't necessarily mean you home is at that level on a long-term test. Same could be said if you scored a 1, you might actually be higher on a long term.

This is why I haven't "fixed" mine yet. But I ordered two new short-term kits (for different rooms) and 1 long-term kit.