Typical air vs. spike days
- Annual average PM2.5 (8.01 µg/m³) reflects usual daily exposure.
- Worst-day peak PM2.5 (21.10 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 Woodstock without contradicting EPA-aligned thresholds.
Local Allergen Load
The local landscape contributes a heavy load of biological particulates that are not always captured in PM2.5 data. Pollen from local oak and pine trees is a major factor in Cherokee County, often coating surfaces in a visible layer of yellow dust. Proximity to areas like Olde Rope Mill Park means higher exposure to seasonal mold spores and plant debris. These large particles are the primary cause of filter loading, where the filter becomes physically blocked, forcing the HVAC fan to work harder. In the humid Georgia climate, these organic materials trapped in a filter can also become a site for microbial growth if not replaced regularly.
Technician's Filter Recommendations
Based on the 0.074 ppm ozone peaks and the 21.1 µg/m³ PM2.5 spikes, I recommend a MERV 11 or MERV 13 filter for the city homes. A MERV 11 is sufficient for most, but if you have respiratory issues, the MERV 13 provides better capture of fine particles.
- Carbon Filtration: Look for a filter with an activated carbon layer; this is specifically designed to trap ozone and other gaseous odors.
- Maintenance: Change your filters every 60 to 90 days, but during the peak of spring pollen, check them every 30 days.
- System Health: A dirty filter reduces airflow, which can cause your AC coils to freeze or your blower motor to burn out.