A new coat of paint or stain can make a room feel fresh again, but it often has the opposite effect on the air quality in your home. According to the U.S. Environmental Protection Agency (EPA), paints, stains and other architectural coatings produce about 9 percent of the volatile organic compound (VOC) emissions from consumer and commercial products, making them the second-largest source of VOC emissions after automobiles.
VOCs are carbon compounds that evaporate at room temperature and react in sunlight to help form ground-level ozone, an integral component of photochemical smog. VOCs can cause respiratory, skin and eye irritation; headaches; nausea; muscle weakness; and more serious ailments and diseases, according to the EPA. Formaldehyde, a VOC commonly found in paint, is a probable carcinogen. The EPA has found that indoor concentrations of VOCs are regularly up to ten times as high as outdoor concentrations, and can climb up to a thousand times as high as outdoor concentrations when you are applying paint.
This overview covers the environmental and health impacts associated with most types of paint on the market. A good coat of paint should last years, so your choice is significant for your home, your health and the environment.
VOCs AND BEYOND
When considering the VOC content of any product, keep in mind that EPA and state and local rules are intended to reduce emissions of VOCs that cause smog, not to improve indoor air quality. These rules allow paints labeled “zero-VOC” or “no-VOC” to contain up to five grams of VOCs per liter (g/L) in addition to VOCs that have been exempted from the rules. The paint standard developed by the nonprofit organization Green Seal sets more comprehensive environmental requirements, but is considered easy to meet by manufacturers. Low- and no-VOC paints may also contain other compounds that affect air quality. While some of these are known and can be avoided, others are not. Manufacturers are not required to disclose all the chemicals used in their products; some ingredients are deemed proprietary information or are used in such small quantities that they do not have to be reported.
Beyond VOCs, many paints are made with toxic substances and chemicals that come from nonrenewable resources or are energy-intensive or polluting to produce, so even no-VOC paints and stains can affect the environment.
COMPOSITION OF PAINT
Paint has three main components: Pigment gives it color; the binder or resin makes the pigment stick when the paint is applied and forms a solid layer of paint; and the carrier or solvent keeps the paint in liquid form and evaporates once the paint is exposed to air. Other additives are sometimes used to thicken paint (such as chalk, which is nontoxic) or give it characteristics such as mold resistance (which requires toxic materials).
Pigment contributes to a paint’s emissions in a small but significant way. Much of the latex and oil paint sold in stores comes as white base paint, and colorants (composed of pigments in liquid form, soaps and sometimes solvents) are added to create the desired color at the time of purchase. Because pigments add some amount of VOCs and sometimes toxins to the base paint, actual VOC emissions will almost always be higher than those quoted on the base paint. The deeper the hue, the more pigment needed, and therefore the more VOCs the colored paint contains. If you must paint in deep, dark shades, consider purchasing paint from a no- or low-VOC line that includes no- or low-VOC pigments.
Toxic substances used in a pigment should be listed on its Material Safety Data Sheet (MSDS). Avoid cadmium, chromium, mercury and other heavy metals. Titanium dioxide, which gives white latex and oil paints their base color and accounts for about 25 percent of these paints by weight, is very energy intensive to produce, so paint containing it creates a certain amount of energy-related pollution before accounting for the binder and carrier.
We differentiate between types of paint based on their binders since the binders tend to dictate a paint’s characteristics and applications. Both the binder and the carrier, however, can contribute to a paint’s overall environmental and health impact.
LATEX PAINTS (acrylic and vinyl acetate binders)
Because they use water as the carrier rather than petroleum-based solvents, latex paints have lower VOC levels than oil-based paints. While they don’t cover stains as well as their oil-based counterparts, low- and no-VOC latex paints perform well for most household applications, and high-quality latex paint can be as durable as an oil paint. Latex paint actually contains no latex, so it won’t affect people with latex allergies.
Latex paint cleans up easily with water, so you don’t need harsh VOC-emitting solvents to work with it. It can also be “recycled” by combining leftovers; oil paints cannot be recycled in this way.
Using recycled latex paint avoids the manufacturing impact, but recycled paint may not be made of low-VOC paint, so it is best suited to well-ventilated areas like the interior of a garage or shed. Standards for recycled low-VOC paints are being developed. The Product Stewardship Institute hosts this list of recycled paint manufacturers.
We recommend using paints that are free of fungicides and biocides like formaldehyde. Although latex paints are biocide free to begin with, almost all manufacturers add synthetic biocides, or “can preservative,” to extend shelf life. Manufacturers are not required to list biocides on a paint’s MSDS because they are added in such small amounts, but some paints are labeled biocide- or fungicide-free. If you do not see this on the label and want to avoid biocides, call the manufacturer to determine if biocides are included in the formulation.
One hundred percent acrylic paint is more water resistant than vinyl acetate paint and is good for kitchen, bath and exterior applications. Vinyl acetate paint is adequate for most indoor applications and is less expensive. Look for solids content of over 30 percent to hide stains, cover in fewer coats, and cover more surface area per gallon. This information should appear on the paint’s label or Technical Data Sheet (TDS).
See GreenHomeGuide’s Latex Paint Directory for low- and no-VOC paints reviewed and approved by our subject editors.