Had a question emailed to me about “outgassing”? What does it mean?

Outgassing means that there are one or more toxic chemicals present in a substance or material which are volatile, that is, they evaporate out of the substance or material into the air where you can breathe them.

Outgassing refers to the fumes (which are gasses) coming out into the air.

One of my most vivid childhood memories happened in a grade school science class. A bottle of formaldehyde was left open on a counter (I don’t know why) and it evaporated completely over a period of hours. The bottle was full and then it was empty. That’s evaporation of gasses.

Outgassing can occur quickly or over time. Often you can smell the chemicals, but not always.

When you are putting gasoline in your car and can smell it, that’s outgassing. And when you spill some on your shoes and the odor goes away after half an hour, the gasoline has “gassed out.”

But chemicals can also be bound up so they are “time-release.” An example of this is the formaldehyde resins used on permanent-press fabrics. The formaldehyde is bonded into the resin so it releases slowly over time. Same thing with particleboard. Another resin containing formaldehyde that releases over time. Many, many plastics time-release their toxic chemicals.