Units still without MERV-13 smoke filtration after Phase 1

Installed filter rating when assessors left, among the 68,250 units with readable filter data; each square represents 1%

Left below MERV-13 (49% — 33,554 units) MERV-13 or better installed (51% — 34,696 units)

Source: CalSHAPE assessment data; data reflect conditions at time of assessment, 2021–2024. During Phase 1 maintenance, assessors installed the best filter each unit could support. Shares reflect the installed ("as-left") MERV rating: MERV Installed Rating (V1 protocol) or as-left filter MERV (V2 protocol); 2,894 units without a readable rating are excluded.