Development of biodegradable poly(lactic acid) (PLA) nanofibrous membranes (NFMs) signifies a promising approach to provide effective air purification, while evading the dilemma of plastic pollutions. It is unfortunately thwarted by the intrinsically low electroactivity and poor polarization capability of PLA, leading to insufficient electrostatic adsorption and PM capturing, especially in challenging circumstances of high humidity and high PM concentration. Herein, multiscale dual-function PLA NFMs featuring increased electroactivity coupling the triboelectric nanogenerator (TENG)-based self-powered mechanisms are demonstrated for efficient respiratory healthcare with enhanced humidity resistance, as well as wireless intelligent monitoring of physiological characters. To enhance the in situ electret and charge storage mechanisms for the PLA NFMs, we proposed a collaborative strategy of PLA stereocomplexation combined with heterostructure of increased dielectric properties, employing dual-needle electrospinning of electroactive nanofibers (around 790 nm). It facilitated the generation of electroactive phases, largely promoting the dielectric properties, surface potential (5.5 kV), and triboelectric output properties (nearly 16 V) for the PLA NFMs. Benefiting from the refined nanofibers and promoted dielectric properties, the PLA NFMs exhibited an excellent air filtration performance (99.4% removal of PM0.3–2.5, 85 L/min), while providing a desirable air resistance (only ∼200 Pa). This was accompanied by high-sensitivity in situ monitoring of respiratory characters such as coughing, breathing and speaking, essentially arising from the respiratory vibration-driven generation of electrical signals. Featuring remarkable filtering performance and antibacterial properties, the proposed biodegradable electroactive NFMs are highly appealing for respiratory healthcare and wireless monitoring in an ecofriendly manner.The MSDF-PLA NFMs featuring high dielectric properties and electroactivity were developed base on a dual-needle electrospinning technique, enabling excellent self-sterilization, efficient PM removal, increased humidity resistance, sensitive respiratory monitoring and full degradation.