Typical air vs. spike days
- Annual average PM2.5 (9.27 µg/m³) reflects usual daily exposure.
- Worst-day peak PM2.5 (34.66 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 South Lyon without contradicting EPA-aligned thresholds.
Local Pollen and Mold Loads
Seasonal loads in South Lyon are driven by the surrounding agricultural areas and local parks. Tree pollen in the spring and ragweed in the late summer provide a heavy biological load that settles on every surface. These larger particles don't just affect your breathing; they act as a physical abrasive inside your HVAC ductwork and on the blower fan. The proximity to the Huron River corridor can also lead to higher localized mold spore counts during wet periods. A filter's job is to trap these allergens before they reach your indoor living space, preventing the dust buildup common during seasonal transitions.
Technician Filter Recommendations
Given the PM2.5 peaks above 25 µg/m³, I recommend a MERV 13 filter for most South Lyon homes. This level of filtration is necessary to catch the fine particulates that spike during the worst air quality days. Because ozone also peaks above 0.070 ppm, a filter with an integrated carbon layer is highly effective at reducing gaseous irritants. Follow these technician tips:
- Change your filters every 90 days as a baseline.
- Move to a 60-day schedule during the peak of summer.
- Inspect the filter if you notice increased dust on your furniture.
If your HVAC system is older and struggles with the static pressure of a MERV 13, a high-quality MERV 11 is the minimum acceptable standard to handle the local pollen and dust load. Never use the cheap, see-through fiberglass filters; they offer zero protection against the 34.66 µg/m³ spikes recorded here.