AIR FILTRATION TECHNOLOGIES FOR FINE PARTICULATE MATTER (PM2.5) MITIGATION

INTRODUCTION: Fine particulate matter (PM2.5) is the primary environmental risk factor for global morbidity and mortality, linked to cardiovascular, respiratory, and metabolic outcomes with no identified safe exposure threshold. Since a significant portion of exposure occurs indoors, air filtration technologies have been proposed as a complementary strategy to reduce individual exposure. AIMS: Objectives: To critically analyze the state of the art in air filtration technologies for PM2.5 mitigation by describing physicochemical capture mechanisms, characterizing advances in filter media synthesis methods, examining the regulatory framework for performance classification, and evaluating the methodological comparability of published data. MATERIALS AND METHODS: A narrative literature review was conducted between August 2025 and June 2026 using PubMed, Scopus, Web of Science, and Google Scholar, supplemented by direct consultation of regulatory documents from issuing bodies. Experimental articles, reviews, guidelines, and technical standards published in English or Portuguese were included. Extracted data were organized into four thematic axes corresponding to the specific objectives. RESULTS: Results: PM2.5 capture results from the interplay of five mechanisms with distinct parametric dependencies; this leads to an efficiency minimum between 0.1 and 0.3 micrometers, the position of which shifts according to the medium’s electrostatic charge and face velocity. Electrospinning enables the production of nanofibrous membranes with efficiencies exceeding 99% and lower pressure drops than conventional filters, albeit with productivity rates several orders of magnitude lower than those of industrially established technologies. Biodegradable polyesters and biopolymers demonstrate performance comparable to synthetic polymers, though unresolved gaps remain regarding stability under humid conditions and the safety of incorporated nanomaterials. The ISO 16890 standard replaced EN 779 by introducing classification based on health-relevant particle size fractions and incorporating efficiency testing after electrostatic discharge into the classification value. A cross-cutting finding was that the test conditions adopted in material studies are heterogeneous and largely unreported: among the seven studies synthesized, only two specified the challenge aerosol and none reported the charge state of the media, which precludes direct comparison of the published performance values. FINAL CONSIDERATIONS: Final Considerations: Indoor air filtration serves as a complementary measure to—rather than a substitute for—source emission control. Evidence regarding benefits for clinical outcomes remains of low certainty, although effects on cardiovascular biomarkers have been documented. The standardization of test conditions in material studies, the characterization of performance over the service life, and the generation of evidence in naturally ventilated buildings constitute the main identified gaps.

PALAVRAS-CHAVE: Material Particulado; Filtros de Ar; Poluição do Ar em Ambientes Fechados; Nanofibras; Saúde Ambiental.