GIven the tight envelope of our home, the avoidance of Volatile Organic Compounds, or VOCs, becomes even more important. Chemicals in paint, cabinets, carpets, and anything that is brought into the house can continue to emit from their source over time. Carpet absorbs these compounds and emits them over an even' longer period.
Paint chemistry is very mysterious, given the competition among manufacturers and their reluctance to share the ingredients of their "secret sauce". But given that paint occupies so much of the surface of our interiors, and given that we are exposed to the chemicals in paint both during its application and during months and even years afterwards, it is important to know what's in the paint.
Good luck: aside from the degree of VOCs in the paint, manufacturers aren't required to disclose anything on the paint can label. Claims about VOCs are tested before the maker can tout them, however, so that becomes an important way to gauge the "greenness" of the paint.
If you want to know more about what's in your paint or any other product, you can ask for the Materials Safety Data Sheet (MSDS) but you have to take the time to write to the company to get it. Some MSDSs are available onlilne.
For interior primer we are using Benjamin Moore's Eco-Spec brand, which is about as close to zero VOC that you can get. We switched to Pratt & Lambert's RedSeal Porcelain paint for the interior colors, because it's not as pricey but still very low VOC.
Treehugger has a good list of affordable low and no-VOC paints.