The California Air Resources Board (CARB) invites you to participate in our third public workshop discussing updates to the California indoor air quality guidelines for NO₂. CARB hosted two previous workshops in which international and state health agencies, health experts, and community-based organizations presented information on the importance and need for up-to-date indoor guidelines, approaches to consider, and potential challenges. This workshop will cover CARB’s proposed guideline values and the rationale for the approach chosen.