Wildfire Smoke & Your Air Ducts: A Survival Guide
Why standard filters aren't enough when wildfire ash enters your Southern California home's ventilation system.
During the intense wildfire seasons in Southern California, the focus is often on immediate safety. However, once the smoke clears, a hidden danger remains: concentrated ash and particulate matter trapped inside your HVAC system.
1. The PM2.5 Problem
Wildfire smoke is composed of microscopic particles (PM2.5) that are small enough to bypass standard household air filters. These particles settle deep within your air ducts, where they are recirculated every time your AC kicks in.
The "Smoker's Duct" Effect
Even months after a fire, many LA residents report a lingering "campfire" smell. This is because the ash has adhered to the dust buildup inside the ducts, effectively creating a permanent source of odor and irritation.
2. Why Filter Replacement Isn't Enough
Replacing your air filter is a great first step, but it doesn't solve the issue of the ash already sitting in the distribution lines. Think of it like putting a new vacuum bag into a vacuum cleaner but never cleaning the hose—the suction is still pulling through the old debris.
3. When to Call a Professional
If you notice any of the following after a nearby fire, it's time for a professional air duct inspection:
- Gray or black soot around your supply registers.
- Increased sneezing or respiratory irritation when indoors.
- A persistent smoky odor that returns when the HVAC runs.