Microplastics in the atmospheric compartment: a comprehensive review on methods, results on their occurrence and determining factors

While microplastics (MPs) have been studied since the beginning of the century, their occurrence in the atmospheric compartment was only described recently. Based on 33 published papers, this work reviews the literature on microplastic pollution in the air and in atmospheric deposition. Methodologies are examined and compared, along with main results. Currently, the atmospheric compartment is sampled by an array of methods that target either atmospheric deposition or suspended particles in the air. Concentrations vary greatly between studies, due to differences in methodologies and types of targeted samples. The review concludes that while MP presence is confirmed in the atmospheric compartment, knowledge remains very limited at all levels. More work is required to determine factors affecting atmospheric MP concentrations and deposition, although precipitations and human presence are suspected. MPs are transported over long distances in the atmosphere. However, numerical models of this transport and definite assessment of sources are lacking.