The increasing focus on the environment has had a major impact upon the paint industry. Given the recent changes in this area, an informational primer (pun intended) that compares and contrasts conventional paints with the new, more environmentally friendly paint products seems warranted.
Conventional oil-based and latex paints contain higher amounts of volatile organic compounds (VOCs) than their more green counterparts. These volatile ingredients can contaminate indoor air, both during and after application. Most common VOCs are solvents used to maintain the paint in its liquid form and coalescing aids that facilitate film formation after paint has been applied.
VOCs off-gas, or evaporate, as paint dries. Both the solvents used to maintain the liquid properties of paint while in the container and the drying agents that help it dry once it's on the painted surface are released into the air. VOCs can be absorbed by the wallboard or other painted material and can then be released into the air over an extended period of time.
Because they use petroleum-based VOCs and resins rather than water to maintain their liquid state, oil-based paints generally contain a much higher concentration of VOCs than latex paints. The alkyd resins in oil-based paints interact with sun and heat, creating ground-level ozone pollution. In states such as California, New York, and many others, sale of oil-based paints has become highly regulated and/or restricted.
Biocides are common additives in paints that prevent bacteria build-up and spoilage. Biocides evaporate as paint dries and can remain present for years, well after the paint has dried. Biocides often incorporate pesticides, poisonous heavy metals, and/or various preservatives that prevent paints from going bad. Many can also be effective as preventatives against mildew and mold.
Some manufacturers offer paints and stains that do not contain solvents, pesticides, poisons, or that contain only minute amounts of VOCs or biocides. The EarthEasy website provides a list of natural, low VOC, and zero VOC paints. It is important to note that adding colorants to paints listed as 'No VOC' or 'Low VOC' will generally increase the concentration of VOCs by a significant margin. And low VOC and no VOC paints may still contain biocides or fungicides that will evaporate as paint dries.
Although there has often been a general level of dissatisfaction with latex paint vs. oil paint in terms of coverage, sheen, consistency and durability, product manufacturers have continued to improve the performance of latex-based low or no VOC paints. Designers and clients generally support efforts to protect the environment and improve indoor air quality.
A Paint and Coatings Industry article points out that product claims, labeling, and actual use and performance must be kept in mind when evaluating the total environmental advantages of ecologically friendly paints. As one example, an energy-efficient paint coating may contain more VOCs, but it may also help the painted home or other structure save energy and thus reduce greenhouse gas emissions at the power plant.
Many paint manufacturers claim their product is low or zero VOC, but these products may simply be within the standard now that government standards for acceptable levels of VOC have recently been lowered. Paints that don't perform well and thus require frequent reapplication may actually be worse alternatives both economically and environmentally. For example, three coats of a low VOC paint will emit roughly three times more VOCs than a product with the same VOC content that requires a single application over the same time period.
Solvents needed for clean-up, recycling of paints and paint containers, proper storage of paints, and proper ventilation during application are all important considerations when assessing the environmental impact of any particular paint type.
Green Seal, a nonprofit environmental organization that certifies products as eco-friendly, has published updated standards for paints and coatings and also maintains a list of products that meet Green Seal's standards. It is one of the many websites dedicated to promoting environmentally responsible products and services.
Resources:
The Promise of Green Paint, New York Times article by Sarah Kershaw.
Supply of Oil-Based Paint Thins as New Rule Takes Effect: Sale Restrictions Aim to Curb Ozone Pollution, Washington Post article by Margaret Webb Pressler that discusses restrictions on oil-based paints in the Mid-Atlantic states.
Green Seal Environmental Standard for Paints and Coatings, 2008 compliancy standard that defines conditions for Green Seal certification (PDF file).
Green Seal Report: Wood Finishes and Stains, 2005 Green Seal report on wood finishes and stains (PDF).