Typical air vs. spike days
- Annual average PM2.5 (8.52 µg/m³) reflects usual daily exposure.
- Worst-day peak PM2.5 (39.15 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 Dickinson without contradicting EPA-aligned thresholds.
Local Allergen and Humidity Factors
In this part of Galveston County, the proximity to Dickinson Bayou and the coast creates a high-humidity environment that favors mold growth and heavy pollen cycles. These biological loads act as a constant physical weight on your HVAC filters. Unlike dry dust, local pollen and mold spores are often damp and sticky, which causes them to adhere to the filter media and the evaporator coils more aggressively. This reduces airflow and forces the blower motor to work harder. Residents should expect heavy seasonal surges in oak and ragweed pollen, which can quickly saturate a filter even if the outdoor PM2.5 levels appear low on a given day.
Technician's Filter Recommendations
Based on the PM2.5 peaks exceeding 39 µg/m³, I recommend using a MERV 13 pleated filter. This rating is high enough to capture the fine particulates seen during peak events without excessively restricting airflow in most modern systems. Because the max ozone levels reach 0.0806 ppm, look for a filter that includes an activated carbon layer. Carbon is the only effective way to neutralize the gas-phase pollutants and odors associated with high ozone days. In the Dickinson climate, filters should be changed every 60 to 90 days. The combination of high humidity and seasonal pollen creates a thick mat on the filter surface that can lead to coil freezing or compressor strain if left too long.