Microplastics in Airborne Particulate Matter: A Comprehensive Review of Separation Techniques, In Vitro Toxicity and Health Impacts

Microplastics (MPs) are emerging airborne pollutants that can migrate through various environmental pathways, with air representing one of the most critical exposure routes. Their occurrence within suspended particulate matter (PM)—a major atmospheric pollutant associated with respiratory, cardiovascular, and neurological diseases—further amplifies the risks posed by air pollution. The main sources of airborne MPs include tire and road wear, degradation of larger plastic debris, and wind-driven resuspension from soil and landfills. This review provides a comprehensive synthesis of current knowledge on airborne MPs, integrating methodological and toxicological perspectives. It summarizes sampling and separation procedures (filtration, chemical digestion, density separation) and analytical techniques for qualitative and quantitative identification. Particular emphasis is placed on the toxicological implications of MPs, including oxidative stress, inflammatory responses, and potential carcinogenicity, as revealed by in vitro and mechanistic studies. In light of the absence of standardized methodologies, this work highlights the urgent need for harmonized protocols linking environmental monitoring with biological toxicity assessment. By combining information on analytical workflows and cellular responses, this review serves as a key reference for developing environmentally relevant experimental designs and evaluating health risks associated with airborne microplastics. It therefore bridges the gap between environmental analysis and toxicological research, outlining future priorities for methodological standardization and risk assessment.