Typical air vs. spike days
- Annual average PM2.5 (10.39 µg/m³) reflects usual daily exposure.
- Worst-day peak PM2.5 (39.23 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 Katy without contradicting EPA-aligned thresholds.
Seasonal Load and Filtration
Pollen and mold are the primary drivers of filter clogging in this region. The proximity to the Katy Prairie and local spots like Mary Jo Peckham Park means seasonal oak, ragweed, and grass pollens are heavy. High humidity levels also contribute to mold spore activity. These biological particles settle in ductwork and saturate filter media, reducing airflow and forcing the blower motor to work harder. In the city, the transition between seasons usually brings a visible layer of yellow dust that mirrors what is being pulled into your return air vents.
Technician's Filter Recommendation
Because PM2.5 levels exceed 39 µg/m³ during peak events, a MERV 13 filter is the professional recommendation for local homes. Standard fiberglass or low-MERV pleated filters will not capture the fine combustion particles or smoke that characterize these spikes. Additionally, since ozone peaks hit 0.0921 ppm, a filter with an activated carbon layer is highly effective at neutralizing odors and chemical vapors. In this climate, filters should be inspected monthly and replaced every 60 to 90 days. If you notice a gray or dark brown film on the pleats, the filter is at capacity and is restricting your system's efficiency. For those with high sensitivity, pairing a MERV 13 with a bedroom HEPA unit is the most effective strategy.