Keeping Your Home Safe from Volatile Organic Compounds
In response to the January 2025 fires in the greater Los Angeles region, Alex L. Sessions, Caltech’s Nico and Marilyn Van Wingen Professor of Geobiology, answers an audience-submitted question about food safety in homes affected by soot and ash.
For homes affected by soot and ash from the recent fires: Are foods kept in plastic bins protected from VOCs? What about materials in cabinets or closets?
Volatile organic chemicals (VOCs) are molecules that are small enough that they can easily be liquids or gases at room temperature. Not all are harmful: Gasoline (harmful) and perfume (not harmful) are both common examples. This property means the VOCs can travel either through the air (as gases) or on particles (as liquids stuck onto the particle surface). In a big fire, they probably do both.
Having your stuff stored inside of a closed cabinet or bin will definitely help prevent contact with VOCs, but unless they are airtight — like a sealed Tupperware — there is a chance that they could let some amount of gaseous VOCs in.
For food, anything that was in air-tight glass or metal should be fine; VOCs do not permeate those materials. Plastic is a tougher call since VOCs can slowly permeate some kinds of plastics. Thicker plastic materials are certainly better than thin ones; I would be cautious of anything stored in a thin plastic bag. For nonedible materials (woodwork, carpets, furniture), just try to take advantage of the fact that VOCs will evaporate on their own.
An analogy: Say you went away on vacation and forgot to take out the kitchen trash. When you return, the whole house smells. Everything you would do to get rid of those garbage smells will work for fire-derived VOCs too: open windows, tumble dry fabrics, set things outside in the sun, wipe down surfaces, etc.
—Alex L. Sessions, Nico and Marilyn Van Wingen Professor of Geobiology
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