Concentrations of many VOCs are consistently higher indoors — up to 10 times higher — than outdoors, which is the reason you are experiencing such reactions.
It takes a while for VOCs to off-gas — as long as two years for some products — and, of course, in a closed room, the effects on you and your family can be severe.
Some people react more than others to VOCs — usually those with existing health problems, such as asthma. “Adverse health effects in some sensitive populations,” as the EPA puts it.
There are, however, a lot of products in the marketplace that were once heavy on VOCs that are now billed as having low levels or none.