California Air Resources Board

CARB is evaluating the health evidence and approaches for updating California's indoor air quality guidelines for NO₂ to protect public health. 

CARB hosted two previous workshops (May 16, 2023 and May 30, 2024) 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.

You're invited to participate in the next workshop, on November 19, 2025 to discuss CARB’s proposed guideline values and the rationale for the approach chosen. The presentation and materials will be made available.