Typical air vs. spike days
- Annual average PM2.5 (8.42 µg/m³) reflects usual daily exposure.
- Worst-day peak PM2.5 (37.94 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 San Antonio without contradicting EPA-aligned thresholds.
Pollen and Dust Load
San Antonio residents face a relentless cycle of allergens that put a heavy physical load on HVAC filters. From the intense Mountain Cedar season in winter to the heavy Oak and Ragweed seasons, biological particulates are a constant presence. The humidity near the San Antonio River and local creek beds also contributes to mold spore counts. These aren't just health irritants; they are physical debris that clogs filter media, reduces system airflow, and can lead to expensive blower motor repairs if the filter isn't swapped regularly.
Technician's Filter Recommendation
Given the peak PM2.5 levels of 37.94 µg/m³ and the high ozone max of 0.08 ppm, a standard fiberglass filter is insufficient. I recommend the following for local homes:
- Filter Grade: Upgrade to a MERV 13 pleated filter. This is the minimum grade required to effectively capture the fine particulates seen during the city's worst-day spikes.
- Ozone Control: Use a filter with activated carbon. This is the only effective way to reduce the 0.08 ppm ozone peaks as air circulates through your HVAC system.
- Maintenance: Change your filter every 60 days during peak summer and winter months. The combination of high run-times and heavy pollen/dust in the city will saturate filters quickly.
- Pro Tip: Ensure your filter rack has a tight seal; even a MERV 13 won't help if air is leaking around the edges of the frame.