Typical air vs. spike days
- Annual average PM2.5 (8.10 µg/m³) reflects usual daily exposure.
- Worst-day peak PM2.5 (32.50 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 Gretna without contradicting EPA-aligned thresholds.
Regional Pollen and Humidity Factors
In Jefferson Parish, the primary load on your air filter isn't just industrial—it is biological. The proximity to the Mississippi River and local wetlands ensures high humidity levels that keep mold spores active for most of the year. Seasonal pollen from oak and pecan trees creates a heavy, sticky dust that enters the home through open doors and window seals. This organic material often binds with moisture in the air, creating a thick layer on HVAC coils. Regular filter changes are necessary to prevent this debris from restricting airflow and causing the system to freeze up during the peak of summer.
Technician's Filter Recommendations
Based on the peak PM2.5 levels exceeding 25 µg/m³, I recommend using a MERV 13 pleated filter for most residential systems. A MERV 13 is dense enough to capture the fine particulates that spike during the city's worst air quality days. If your HVAC system is older and has a weaker blower motor, a MERV 11 is a solid alternative that offers better airflow while still providing superior protection over standard fiberglass filters. In this climate, you should follow these maintenance rules:
- Change frequency: Every 60 to 90 days. If you have pets or high foot traffic, check it at 30 days.
- Seal check: Ensure the filter fits tightly in the rack; any gaps allow unfiltered air to bypass the media.
- Humidity control: Keep indoor humidity below 50% to prevent mold growth on the filter media itself.