Recent global viral outbreaks have highlighted the urgent need for protective face masks that combine high filtration performance with environmental sustainability. Herein, we developed a biodegradable, breathable, and antiviral nanofiber (NF) filter composed of quercetin (QU) and poly(ethylene oxide) (PEO) via a solution-blowing (SB) technique. The resulting QU/PEO NF filter exhibited a non-woven morphology with high porosity and excellent mechanical durability, showing a high yield strength of 30 MPa. It also demonstrated rapid biodegradation in soil, confirming its eco-friendly nature. Filtration tests showed a high particulate matter (PM) removal efficiency of up to 96.2% at an airflow rate of 20 L/min, with a low pressure drop, outperforming commercial mask filters. In addition, antiviral assays confirmed that the NF filter effectively reduced viral infectivity, while showing protective effects against oxidative stress and inflammation in skin cells. These results demonstrate the strong potential of the QU/PEO NF filter as a next-generation non-woven material for personal protective equipment, requiring effective viral protection, excellent breathability, skin compatibility, and environmental sustainability.