Typical air vs. spike days
- Annual average PM2.5 (8.03 µg/m³) reflects usual daily exposure.
- Worst-day peak PM2.5 (33.48 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 Dacula without contradicting EPA-aligned thresholds.
Local Dust and Pollen Load
In Gwinnett County, the air quality isn't just about regulated pollutants. Seasonal pollen from heavy oak and pine canopies creates a massive physical load on air filters. Mold spores also thrive in the humid Georgia climate, especially near local spots like Little Mulberry Park. These biological particles are much larger than PM2.5, but they clog filter media quickly. If you notice a fine yellow dust on your porch, that same material is being pulled into your return air vents. This seasonal surge requires a filter that can handle high volume without collapsing or restricting airflow to your blower motor.
Technician's Filter Recommendation
Given the PM2.5 spikes exceeding 33 µg/m³, I recommend a MERV 13 pleated filter for most modern HVAC systems. MERV 13 is the entry point for capturing the fine combustion particles and smoke that make up PM2.5. However, because ozone peaks reach 0.072 ppm, adding a filter with an activated carbon layer is a smart move to help neutralize gaseous irritants. If your system is older and a MERV 13 causes too much static pressure, drop back to a MERV 11 and supplement with a standalone HEPA unit. In this part of Georgia, humidity and high pollen counts mean you cannot wait six months to change a filter. Inspect your filter every 30 days and replace it at least every 60 to 90 days. A gray or heavy filter is a sign your system is working too hard to pull air through a wall of dust.