Typical air vs. spike days
- Annual average PM2.5 (8.09 µg/m³) reflects usual daily exposure.
- Worst-day peak PM2.5 (35.27 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 New Berlin without contradicting EPA-aligned thresholds.
Seasonal Particulate Loads
Seasonal loads in this part of Waukesha County are driven by heavy tree pollen in the spring and ragweed in the fall. Green spaces and local parks contribute to a high biological particulate count that enters the home through open windows or door gaps. This organic matter, combined with indoor dust, creates a thick layer on HVAC filters. In the local climate, humidity can also lead to increased mold spore activity, which adds another layer of stress to your home's filtration system. These particles are often larger than PM2.5 but are equally important to filter out to prevent system wear.
Technician's Filter Recommendations
I suggest using a MERV 13 filter to handle the PM2.5 spikes that reach 35.27 µg/m³. A MERV 13 is efficient at trapping the fine particles that standard filters miss. Given the ozone peaks of 0.079 ppm, a filter with an integrated carbon layer can help neutralize odors and gaseous pollutants that often accompany high-ozone days.
- Replacement Schedule: Change your filters every 2 to 3 months.
- Visual Checks: If you notice the edges of the filter are turning dark or if there is visible dust buildup on your supply vents, you are waiting too long between changes.
- Baseline: For homes with respiratory sensitivities, a MERV 13 is the professional standard, while a MERV 11 should be the absolute minimum for any local system.