Microplastics in the atmosphere: a review

Microplastics (MPs) are ubiquitous environmental contaminants of considerable persistence and have been a global concern for the past decade. Recently, atmospheric MPs have gained attention. The presence of MPs in the air has been reported from different regions and in air masses over water bodies, demonstrating MPs’ capability of long-range transport and wide spatial distribution away from their source of origin. This review of atmospheric MPs raises questions about the validity and legitimacy of approaches adopted for assessing MP in indoor and outdoor aerosols. The review also provides insight into active and passive sampling techniques and draws attention to the use of the data produced. MP abundance in the atmosphere varies widely among studies due to the disparities in methods employed and the heterogeneity in reporting, making comparisons across spatio-temporal domains infructuous. This review also highlights the paucity of data on atmospheric MPs, and the eminent need to harmonize the methodology for generating a useful comparable dataset that can be used for human health risk assessments.