Atmospheric Deposition of Organic Pollutants: A Comprehensive Review of Sampling and Analytical Methodologies

Atmospheric deposition of organic pollutants plays a crucial role in the transport and fate of contaminants in the environment, with implications for ecosystem health and human exposure. Persistent organic pollutants (POPs), polycyclic aromatic hydrocarbons (PAHs) and microplastics are increasingly recognized as transboundary threats due to their long-range atmospheric transport and accumulation. Despite international regulatory efforts, such as the Stockholm Convention and the EU's new air quality directives, data on deposition fluxes remain sparse and highly variable due to methodological inconsistencies and analytical limitations. Key challenges arise from the trace levels of target analytes, the complexity of environmental matrices and the absence of standardized sampling and analytical protocols. Overcoming these limitations is crucial for establishing robust monitoring systems and supporting evidence-based risk assessments. This review highlights recent developments and methodological innovations in the study of bulk atmospheric deposition of organic pollutants. Key areas of focus include (1) a critical evaluation of sampling devices and strategies, with an emphasis on bottle-funnel and passive sampler designs that influence data quality, (2) advances in extraction and sample preparation techniques, including liquid-liquid and solid-phase extraction tailored to trace-level environmental contaminants, (3) identification of key analytical constraints and variability in recovery efficiencies across different compound classes and analytical workflows, (4) a synthesis of over 160 peer-reviewed studies offering a comparative framework for future monitoring campaigns and harmonization of analytical approaches.