Typical air vs. spike days
- Annual average PM2.5 (8.85 µg/m³) reflects usual daily exposure.
- Worst-day peak PM2.5 (27.91 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 Richardson without contradicting EPA-aligned thresholds.
Regional Pollen and Mold Loads
Pollen and mold are the constant, invisible loads on air filters in North Texas. Near the Spring Creek Nature Area, local flora releases heavy amounts of ragweed, oak, and cedar pollen depending on the season. These large biological particles are sticky and quickly clog standard fiberglass filters. Humidity levels in Dallas County also contribute to mold spore activity. Even when PM2.5 levels are low, the sheer volume of biological material in the air during a local pollen dump can restrict HVAC airflow within weeks. This puts unnecessary strain on your blower motor and reduces the efficiency of your cooling coils, making regular filter checks a mechanical necessity.
Technician's Filter Recommendations
Because PM2.5 peaks exceed 25 µg/m³, I recommend a MERV 13 pleated filter for most modern HVAC systems. A MERV 13 is dense enough to capture the fine soot and smoke particles that characterize peak days without overly restricting airflow, provided your system is rated for it. Given the ozone spikes near 0.080 ppm, look for filters that include a layer of activated carbon. Carbon is the only effective way to neutralize ozone gas as it passes through the return air. In this part of Texas, the combination of high pollen and humidity means you should check your filter every 30 days and replace it at least every 60 to 90 days. If the filter media is turning grey or black, it is successfully capturing the local dust load. Adding a standalone HEPA unit in high-traffic rooms is a smart secondary measure for those sensitive to the local 9.7% asthma rate.