2024 Yes Indoor ozone: Concentrations and influencing factors https://onlinelibrary.wiley.com/doi/abs/10.1111/ina.12942 Nazaroff, William Multiple Countries Observational Epidemiological Ozone (O3) Chemistry Offices Residences School Surface reactions Ventilation Analysis of ~2000 buildings found indoor ozone levels average 4-6 ppb, ~25% of outdoor levels. Air exchange rates and surface reactivity drive variability. Activated carbon filters offer effective mitigation, especially in densely occupied schools. 2021