Can you purchase exterior low-VOC paint?

The good news is that there are now low-VOC products available for a surprising number of building and remodeling uses. The bad news is, they are still few and far between, even if they're gaining in number and variety every year.

For example, sealers and coatings for indoor/outdoor uses -- wood, stone and even carpet -- can be found in a variety of low-VOC, nontoxic formulations. This is a perfect solution if you already have, or are using, natural materials, since you're not adding toxins. But another important purpose of sealants is to prevent off-gassing, or chemical evaporation, from the things they're sealing and protecting.

Many of today's building materials are full of gross chemicals. Plywood, particle board and other not-quite-wood products are full of acetone and formaldehyde. While acetone is not technically a VOC, it's a serious toxin. Most polyurethane wood finishes have another toxin that slowly builds up inside your body, and much new carpeting even contains a number of narcotics. By applying a bio-safe sealant to these materials, you're not only protecting them, but also yourself: It's not just the paint or sealant you use, but what you're applying it to.

Now, even coatings labeled "environmentally friendly" or "zero-VOC" can still contain toxic ingredients, just not those that are prohibited by government regulations. You shouldn't go pouring house paint on your morning cereal just yet. When searching for the most eco-mindful paint, indoor or outdoor, check those cans and labels.

Next up, we'll look at a few more rules of thumb for choosing eco-friendly paint.

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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