Typical air vs. spike days
- Annual average PM2.5 (9.56 µg/m³) reflects usual daily exposure.
- Worst-day peak PM2.5 (23.20 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 Edwardsville without contradicting EPA-aligned thresholds.
Regional Pollen and Mold Trends
Seasonal shifts in the Mississippi River valley bring heavy pollen and mold loads that often bypass standard low-grade filters. Spring tree pollen and late-summer ragweed are the primary culprits for residents. Humidity levels in the region also contribute to mold spore activity, which can settle in ductwork if not properly managed. These biological particles are larger than PM2.5 but are produced in massive quantities, physically clogging filters and reducing airflow if the media isn't swapped out regularly. Keeping a fresh filter during these transitions is the best way to protect your HVAC blower motor from unnecessary strain.
HVAC Filter Recommendations
For Edwardsville homes, a MERV 11 filter is the standard baseline. However, because ozone peaks reach 0.0732 ppm, I recommend a filter with an activated carbon layer to help neutralize gaseous pollutants. If you find your home gets dusty quickly or you are sensitive to the 23.2 µg/m³ PM2.5 spikes, upgrading to a MERV 13 is a smart move. These thicker filters have more surface area and can handle higher particulate loads without killing your blower motor. Change these filters every 60 to 90 days. If you have pets or high foot traffic, stick to the 60-day mark to prevent static pressure issues. Avoid cheap fiberglass filters, as they do almost nothing to stop the fine particulates and ozone-related irritants identified in local air data.