Radical-induced autoxidation dominates squalene oxidative aging under environmental conditions.

Radical-induced autoxidation, not ozone, dominates squalene aging in indoor environments, with a 1st-order decay driven by reactive oxygen species formation.

• Why it matters: Understanding the primary oxidation pathways of skin oils under realistic indoor conditions is crucial for assessing skin aging and related health effects, as current views focus mainly on ozone.
• What they did: The study used squalene exposure experiments in laboratory flow reactors and indoor air to compare oxidation pathways, measuring decay rates, ROS, VOCs, and oxidation products, including highly oxidized hydroperoxides.
• The result: Findings show that radical autoxidation, rather than ozone alone, governs squalene aging indoors, producing higher ROS yields and oxidized products, which challenges the ozone-centric paradigm.