Ask the Expert Question-and-Answer Archive

by Ron Joseph

June, 2004

Solvent Evaporation from Archetectural Paint

Q. Architectural paints emit VOCs when applied. I have found plenty of information supporting the need for careful application. However, if a building is flushed out thoroughly after paint application, will the paint continue to emit pollutants over time? Can the VOC's emitted from the paint be sequestered in carpet and other finishes, thereby prolonging the indoor health effects of VOCs?

A. Thanks for your e-mail. I'm not an expert on indoor air quality but here is my opinion for what it's worth. The VOCs that are emitted from paints are predominantly solvents which are used during the paint formulation. After the paint has been applied the solvents evaporate, and the extent to which they leave the painted substrate depends on the air movement in the surrounding space, and the ambient temperature. For the most part we expect that the solvents evaporate during the first few hours after the paint has been applied.

With regard to architectural paint which is usually water based the VOC content is very low and therefore the extents of the emissions are also low. Most solvents are lighter than air but a few might settle to the ground. By looking at an MSDS of the coating you can determine which solvents you're dealing with and then refer to various references to determine which, if any are heavier than air.

If the space is well ventilated after painting then I would imagine that most of the solvents will evaporate fairly quickly. I assume from your question that you might be dealing with a client who is suffering from some form of chemical inhalation and is assuming that this might come from the paint. If that is the case it is possible to analyze some of the carpet or other furnishings to determine what comes off. Somehow, I do not believe that is due to the paints that can be confirmed analytically.

Paints also contain a small concentration of plasticizers and resins that have extremely low evaporation rates, and it is possible that these can partially evaporate over a prolonged period of time. I suppose that somebody who is extremely sensitive to small concentrations of chemicals might be affected, but generally this does not seem to be the case since millions of homeowners appear to be unaffected after painting has been performed.

Please do not hesitate to get back to me if I can be of further help.

Best wishes,

Ron Joseph