By Alice Delia —
It’s all about the marketing. The surface coatings (paint, varnish, lacquer, etc.) industry has been very successful at convincing us we can act “green” by using a low-VOC (volatile organic compounds) or no-VOC paint. If you think about it, how is that possible? The VOCs serve a purpose so how is that purpose being fulfilled if there aren’t any VOCs? The only answer is that something else is being used to provide that function.
What replaced the VOCs?
VOCs. It sounds ridiculous, but the surface coatings industry replaced “traditional” paint VOCs with other VOCs. Here’s where it gets interesting. There are several definitions for VOCs and by selecting a specific definition a product can have “no VOCs” based on that definition.
40 CFR § 51.100 (s)† states:
Volatile organic compounds (VOC) means any compound of carbon, excluding carbon monoxide, carbon dioxide, carbonic acid, metallic carbides or carbonates, and ammonium carbonate, which participates in atmospheric photochemical reactions.
† Code of Federal Regulations – Protection of Environment – Air Programs
Atmospheric photochemical reactions refers to those chemical reactions that are powered by the sun’s energy to produce ozone or other components of ground level smog, which is relevant for outdoor VOCs but much less so for VOCs found indoors. The more inclusive definition is any chemical compound containing carbon and hydrogen with a boiling point range of approximately 50 °C to 250 °C (120 °F to 480 °F), i.e., chemical compounds that are primarily in the gas phase at room temperature. Hence the “volatile” = gas phase and “organic” = containing carbon, name.
Let’s go back to our chemistry class for a moment. All chemical compounds consist of 2 or more atoms arranged in a particular order or configuration. The properties of the atoms determine what that arrangement will be. One complete configuration or unit makes up one molecule and many, many molecules makes up a chemical substance or compound. So, when you see the concentration of something, let’s say 50 parts per billion (ppb) of formaldehyde which is a fairly typical value, that translates into
The big difference between these two definitions, at least in terms of surface coatings, is the hydrocarbons.
Hydrocarbons, chemical compounds that contain hydrogen and carbon, are by far the largest class of VOCs
Why do we even need VOCs in surface coatings?
VOCs involved in application and drying, forming a smooth and even coating. They are often part of the formulation.
Paint has 3 Primary Components
Pigment – Color can add 10 g/L of VOCs or more
Solvent – Controls evaporation rate, application in liquid form (highest VOCs)
Other possible toxins:
- Heavy metals like chromium and cadmium
- Ozone pollution – how VOCs produce ozone https://www.paint.org/voc-exempt/
Disadvantages of Low VOC
- Dry slower
- More frequent re-application
- Color – Sheen, luster?
Advantages of Low VOC
- Lower odor – However, this can be deceptive since the paint is still off gassing volatile constituents even though the occupants cannot smell anything different.
It has been the EPA’s policy since 1971 that certain organic compounds with a negligible level of reactivity should be excluded from the regulatory definition of VOC in order to focus VOC control efforts on compounds that significantly affect O3 concentrations.