Increasing the grade of media filter can help reduce the concentration of particulate matter (PM) in the indoor air by capturing more fine particles. According to Feature A12: Air Filtration of WELL v2, projects should use filters with a minimum efficiency reporting value (MERV) of 13 or higher, or equivalent, for mechanical ventilation systems that supply air to occupiable spaces. This can help meet the PM 2.5 threshold of 15 µg/m3 or lower for Feature A01: Air Quality.
References: = WELL v2 Feature A12: Air Filtration, WELL v2 Feature A01: Air Quality