Typical air vs. spike days
- Annual average PM2.5 (8.14 µg/m³) reflects usual daily exposure.
- Worst-day peak PM2.5 (44.80 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 Vallejo without contradicting EPA-aligned thresholds.
Coastal Humidity and Pollen Load
Proximity to San Pablo Bay introduces specific air quality challenges, including higher humidity levels that can lead to mold spore accumulation in damp ductwork. Seasonal pollen from local grasses and trees also adds a heavy biological load to your HVAC system. These larger particles often act as carriers for smaller pollutants, making the overall air 'heavier' for your filtration system to process. Without a high-efficiency filter, these allergens settle into your carpets and upholstery, creating a persistent indoor irritant long after the outdoor season has peaked.
HVAC Technician Filter Strategy
Because Vallejo sees PM2.5 peaks well above 25 µg/m³, I strictly recommend a MERV 13 pleated filter. A MERV 8 or 11 will simply allow too many fine particulates to pass through. Given the ozone peaks of 0.0636 ppm, a filter with activated carbon or charcoal media is also highly recommended to help neutralize odors and gases. You should change these filters every 60 days. In this area, the combination of coastal moisture and particulate spikes can cause filters to 'cake' faster than in drier climates. If you notice your AC struggling to keep up or the air feeling 'stale,' check the filter immediately. A clean MERV 13 filter is the most cost-effective way to protect both your lungs and your HVAC equipment's blower motor.