Volatile Organic Compounds
The term “organic compounds” covers all chemicals containing carbon and hydrogen. Volatile organic compounds are those organic compounds that have boiling points roughly in the range of 50-250oC. There are probably several thousand chemicals, synthetic and natural, that can be called VOCs. Of these, over 900 have been identified in indoor air, with over 250 recorded at concentrations higher than 1 ppb. Sources of VOC’s in a typical home include cigarette smoke, household products like air fresheners, furnishings, vehicle exhaust and building materials such as paint, varnish and glues.
Source: Health Canada
Typically, house paint is made up of pigment, binders and solvents. It’s the solvents that thin the paint and make it stick to a wall. It also is responsible for the most VOC’s. As the solvents evaporate, they off-gas fumes which we breathe in. This affects health.
Solvents are oil based or water based. The oil-based paints have more VOC’s.
Pigments and binders as well as mold-inhibitors and preservatives also can contain VOC’s in paint.
Low Odor/Low-VOC Paints
According to the US EPA, standards for low VOC latex paints are 250 g/l and 380 g/l for oil-based paints. However, look for the Green Seal and you’ll see the standard for latex paint is 50 g/l. Most LOW-VOC paints will have around this level, not the EPA level of 250 g/l.
These levels apply to the base paint only. If a manufacturer adds pigment, preservatives or pesticides, the VOC content will be higher. Until recently, many water-based paints added mercury as a preservative. The Green Seal means no toxic chemicals were added.
Even paint that is marketed as NO-VOC can contain VOC’s as soon as pigment is added. At under 10 g/l, this is a good option but it is not likely to be VOC-Free unless you get a plain white paint with no additives.
Natural Paints or Non-Toxic Paints contain ingredients from natural sources. Some sensitive people might react to terpines and citrus oils in these paints. They emit naturally occuring VOC’s. Remember, VOC’s can come from natural sources, too. However, these paints don’t come with the same toxic chemicals as regular paint. That also means they may need to be applied differently. Read the directions and follow them. Some new paints do give as good coverage as traditional paints, without the toxins. Do your homework. Industry seems to be listening to people and more and more manufacturers are creating alternatives. Back in the day, many chemically sensitive had to buy or make their own milk paint.
More on Paints and VOC’s found at these sites:
How Stuff Works
About.com Home Repair
Health Canada’s Indoor Air Quality Painting Checklist for Schools but is good for all