Green Product Category: Paints & Coatings

Paints and coatings are applied as a fluid, and they dry or cure in place. During that process a carrier evaporates, leaving the active agents in place. For most products this carrier was traditionally a volatile organic solvent that turned into an airborne volatile organic compound (VOC) as it evaporated. As with caulks and adhesives, air quality regulations and health concerns have driven a shift toward waterborne products. Evaporating water isn’t a health concern, though other components of the coating or adhesive still generally release some VOCs.

Paints and coatings have their greatest effect on indoor air quality during and immediately after installation. The health hazard is particularly acute for installers. Most conventional products off-gas VOCs, and other chemicals that are added to enhance the performance or extend shelf life of the product. Little scientific data is available on the health effects of many of these chemicals—and even less on the effects of exposure to a combination of such chemicals that may occur in buildings. Quality substitutions, which are lower in toxicity or nontoxic, are available for all of these products.

Minimizing VOC exposure

Even so-called zero-VOC materials may still release small amounts of organic compounds. People with chemical sensitivities should always test these products before applying them on their projects, or having them applied by workers.

Alternatives to conventional paints made from plant-based solvents may also release significant amounts of VOCs, but many people find these compounds less objectionable than those derived from petrochemicals. Again, aside from warnings about solvents with well-known health effects (such as benzene, toluene, or xylene), the scientific community offers little guidance on the distinction between acceptable and problematic VOCs.

In certain categories, the GreenSpec criteria for “low-VOC” products is 50 grams per liter, which is well below even the most stringent VOC regulations in California.

While wet-applied products emit the most VOCs immediately after curing, some continue to off-gas such compounds for a long time. In addition, VOCs emitted during curing can become attached to other surfaces in the space, especially fabrics, and then be re-emitted over time. To reduce this problem, painting should be done with soft surfaces covered and direct ventilation provided until the coating is dry.

For wood-floor finishes, waterborne polyurethane is suggested. It contains no cross-linking agent—a type of chemical that adds hardness but is toxic. Waterborne finishes have been tested for durability, and many wear comparably to solvent-based ones. Installers often prefer waterborne finishing products because they dry quickly, allowing several coats to be applied in one day.

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