Characterization and health risk assessment of airborne microplastics in Delhi NCR

Exposure to airborne microplastics (MPs) is an emerging environmental and public health concern due to their widespread presence and potential toxicity. This study presents the first comprehensive characterization of airborne MPs in Delhi, India, focusing on their seasonal distribution, morphology, chemical composition, and associated health risks. Particulate matter (PM₁₀, PM₂.₅, and PM₁) was collected using active samplers at Lodhi Road during winter (January-March) and summer (April-June) of 2024. Average(± SD) concentrations of MPs were 1.87 ± 0.5 MPs/m³ for PM₁₀, 0.51 ± 0.2 MPs/m³ for PM₂.₅, and 0.49 ± 0.2 MPs/m³ for PM₁, with notable seasonal variation. Fragments (66%) and fibers (32%) were the dominant morphologies, primarily white/transparent and blue in color, ranging from 1-1000 µm in size. Weathering features were observed across particles, chemical analysis identified polyethylene terephthalate (PET) and polyethylene (PE) as the predominant polymers, with trace elements like zinc (Zn), silicon (Si) and aluminium (Al) adsorbed onto their surfaces. Wind rose analysis indicated predominant MP transport from the northwest, highlighting regional source influence. Considering their capacity to carry harmful pollutants, MPs may pose inhalation related health risks. This study underscores the need to integrate MPs into air quality frameworks and advocates for long-term, multi-site monitoring to evaluate their broader public health impacts.