Ventilator mask anti-fog nano coatings use nano-TiO2 (anatase,5-15nm,photocatalytic superhydrophilicity->CA<5deg)/nano-SiO2(10-20nm,filling micro-defects reducing scatter) on transparent PC/PMMA substrates. Physics: exhaled warm moist breath (35-37C,>95%RH) condenses on cold mask (15-25C) as <50um micro-droplets causing Mie scattering compromising vision. Nano hydrophilic coating achieves CA<5deg — condensate spreads as <1um uniform water film — far below visible wavelength (380-780nm) — virtually zero scatter — completely transparent fog-free. Transmission>90% (GB/T 2410-2008). Durability: >500 wipes+EO/H2O2 plasma sterilization maintained. ISO 10993-5(cytotoxicity)/ISO 10993-10(skin irritation — mask contacts facial skin>30min/session — limited contact per ISO 10993-1 — endpoints: cytotoxicity+irritation+sensitization). ISO 80601-2-12:2020. AI-assisted respiratory monitoring demands zero-fog HD visibility. Global ventilator mask market ~$2.8B (2025), CAGR 7.2%.