Do paints without VOCs perform as well?  In the past, many pros complained that low-VOC paints left brush streaks, required more coats and scuffed more easily. While these grumbles still come up, the technology has improved. Findings from a 2007 study conducted by Missouri University of Science and Technology's coatings institute showed many low-VOC paints had performance characteristics similar to and in many cases better than their higher-VOC counterparts, according to the South Coast AQMD. Consumer Reports just gave high performance marks to several low-VOC paints, including Aura, True Value's EasyCare and Glidden's Evermore. Still, surface preparation (getting rid of dirt and grease) is typically more critical with these paints.

Do these eco-paints cost more?  Generally a few more dollars per gallon. Lower-VOC paints range from about $20 to $55, depending on brand.

Can I get whatever color I want?  It depends on the brand and how low you want to keep the VOCs. Many colorants that dealers inject add VOCs. Usually, the darker the color, the more VOCs. However, several brands, including Freshaire, AFM, Mythic, Yolo Colorhouse and Aura, have special colorant systems without VOCs they recommend or require that dealers use. These brands offer anywhere from 55 hues (Yolo) to more than 1,000 (AFM and Mythic).

What's the difference between "low-VOC" and "zero-VOC" paint?  Low-VOC "flat" finish paints usually contain less than 50 g/L of VOCs before adding colorants. For paints with a sheen, look for less than 100 g/L. (Low VOCs are tougher to achieve with oil paints.) A paint marketed as zero-VOC should have 5 g/L or less. But even if you're super-sensitive to fumes, anything under 25 g/L should suffice. "We have an excellent exterior paint that is 17 VOC g/L," says Sam Goldberg, president of American Formulating & Manufacturing in San Diego, which makes Safecoat. "We could make it zero, but we will lose performance. At 17 g/L, there's not a heck of a lot that will bother anybody."

My walls were painted a few years ago and still look good. Should I repaint them with low-VOC paint?  Not unless you hate the color. Most VOCs are released in the first 30 days after application, disappearing as the new-paint smell fades, says David Johnston, co-author of the book "Green from the Ground Up." "Your nose is the most scientific device you have," he says.

Does anyone certify these paints?  Several entities put their seal of approval on paints that meet a variety of environmental and health standards, including lower VOCs. Three widely used groups are Green Seal, Greenguard Environmental Health Institute and Scientific Certification Systems.

So paints marketed as zero-VOC have no potentially toxic stuff inside?  Not always. Some makers still bolster these paints with components like formaldehyde, crystalline silica, acetone and ammonia to help preserve the paint or give it other properties, such as spatter-resistance. If amounts are minute enough, they don't have to be disclosed. Makers that don't use these ingredients, such as AFM, Yolo Colorhouse and Mythic, typically make that clear on labels, marketing materials or Web sites.

Why aren't all paints low-VOC?  Paint makers have a lot invested in traditional formulas. Reformulating products so they still perform well takes time and money. Ratcheting down VOCs doesn't necessarily give you a "greener" paint if it takes three coats to cover a wall or you end up needing to repaint in a year. "You've got to take a holistic view," says Steve Revnew, Sherwin-Williams' director of marketing and product development. Use the Internet to research comments about a brand's performance before heading to the stores.