Typical air vs. spike days
- Annual average PM2.5 (9.11 µg/m³) reflects usual daily exposure.
- Worst-day peak PM2.5 (38.18 µg/m³) is what filtration must handle during bad-air events.
Sections below reference one or both metrics on purpose — that is how HVAC vs. portable guidance differs for Florissant without contradicting EPA-aligned thresholds.
Local Allergen Loads
Seasonal shifts in Missouri bring a heavy load of ragweed, oak, and mold spores. In Florissant, the proximity to various parks and greenways means your HVAC system acts as a giant vacuum for outdoor allergens. These larger particles don't always show up in PM2.5 data, but they are the primary cause of filter 'blinding,' where the mesh becomes completely coated. This increases the pressure drop across your system, forcing the fan to work harder and potentially shortening the lifespan of your blower motor.
HVAC Filter Recommendations
Based on the peak PM2.5 of 38.18 µg/m³, I recommend a MERV 13 pleated filter for local homes. This rating is necessary to trap the fine combustion particles and allergens that a MERV 8 or 10 will miss. Consider these technical tips:
- Ozone Mitigation: Since ozone peaks are elevated, a filter with an integrated carbon layer is a smart upgrade to help strip gases from the air.
- Inspection Schedule: Filters should be inspected monthly and replaced every 60 to 90 days.
- Pet Owners: If you have pets or high foot traffic, stick to a strict 60-day schedule to prevent dust buildup on your HVAC coils.