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 Marrero without contradicting EPA-aligned thresholds.
Regional Environmental Loads
The geography of the area, situated near the Mississippi River and expansive wetlands, contributes to a high seasonal load of mold spores and pollen. Humidity levels remain high year-round, which prevents dust and allergens from dispersing quickly. This creates a thick 'air load' that your HVAC filter must constantly process. Local vegetation, including heavy-pollen producers like oak and grass, peaks in the spring and fall. In local homes, this often results in filters that look 'gray' or 'fuzzy' much faster than the manufacturer's rating suggests, necessitating more frequent inspections.
Technician's Filter Recommendations
Given the PM2.5 peaks of 32.5 µg/m³, I recommend a MERV 13 pleated filter. This rating is specifically designed to capture the fine particles that make up those spikes. Because ozone levels also reach 0.0706 ppm, residents should consider a filter with an activated carbon or charcoal layer. Carbon is one of the few effective ways to reduce ozone concentrations inside the home. In this climate, do not rely on the '6-month' or '1-year' filters often marketed; the high humidity and biological load from the river environment mean filters should be swapped every 60 to 90 days. If you notice a musty smell when the AC kicks on, it is a sign that your filter is overdue for a change or that the humidity is allowing organic growth on the filter media itself.