Zero-VOC paints are those that contain 5 grams (or less) of volatile organic compounds per liter. (EPA standards are sort of like FDA standards for food contaminants, in that zero percent usually doesn't mean what you think.) And even zero-VOC paints can still use ingredients with extra VOCs; for example, tinting a low-VOC paint with colorant can double that level to 10 grams per liter (which, as we'll see, is still very low) [source: Eartheasy].
Low-VOC paints are water based and contain low amounts of heavy metals and formaldehyde, or none at all. The EPA standard here is less than 200 grams per liter for paint (300 for varnishes), but most manufacturers stay at or below 50 grams per liter. If you see the "Green Seal" on a given paint, that means it meets a standard of lower than 50 grams per liter for flat-sheen paint and 150 grams per liter for higher-grade paint [source: Eartheasy].
But one of the most interesting recent trends is a new class of VOC-conscious paints that contain an ingredient that actually absorbs and traps VOCs. They're pretty specific in application so far, but they're an exciting development nonetheless.
MDF-passivating primer is a fairly new type of base coat used for plywood and MDF (medium-density fiberboard) products that off-gas formaldehyde and other non-VOC and VOC toxins. There's even a special paint used for radiators, which can off-gas formaldehyde sometimes for up to two years. Most exciting of all, a product called atmosphere-purifying paint is designed to suck the VOCs out of previous coats of paint and even from the atmosphere of a finished room. It's now used pretty commonly when other furnishings, equipment or carpeting are known to be off-gassing their own deadly chemicals.
While you may still have to go looking for a sensible low-VOC exterior solution, it's comforting to know that it's out there. And now that the paint industry has a reason to develop newer and better products to meet our consumer needs, these and other innovative new ideas mean that environmentally and health-conscious paints and finishes will continue to be refined, invented and developed. And that's good news for everyone!
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