Wildfires, marine layer, and tight new construction — three reasons SoCal IAQ is worse than you think.
Three forces stacking against SoCal IAQ
Wildfire smoke leaves fine particulates that settle in HVAC systems for months. The marine layer drives chronic humidity. Newer Title-24-compliant homes are so airtight they trap whatever moisture and contaminants enter.
Where mold fits in
Mold spores are part of normal outdoor air — typically 1,000–10,000 spores/m³. Indoor counts should mirror or fall below outdoor counts. When indoor spores exceed outdoor by 2× or more, you have an active indoor source that air-purifiers alone cannot fix.
A practical IAQ baseline
Get one professional air-quality test annually. Keep humidity 30–55%. Replace HVAC filters every 90 days with MERV-13 or better. Add a standalone HEPA unit in the bedroom.