Atmospheric Microplastics Emission Source Potentials and Deposition Patterns in Semi-Arid Croplands of Northern China

Abstract

Frequent wind erosion events in semi-arid regions can lead to significant atmospheric microplastic (MP) emissions from croplands. We examine observed and predicted characteristics of atmospheric MPs over cropland in Northern China. Measurements showed that fibers were the predominant morphology, accounting for 69% of the 198 observed MPs. The observed atmospheric MP abundance varied widely, averaging 0.088 # m⁻³ in the absence of air masses passing through near-surface croplands and increasing significantly to 0.26 # m⁻³ when such air masses were present. The predictions of deposition flux for atmospheric MPs over croplands indicated a spatial variation ranging from less than 0.5 g km⁻² day⁻¹ in the north to over 15 g km⁻² day⁻¹ in the south, corresponding to an average of approximately 13.3 g km⁻² day⁻¹. Our findings highlight the dual role of surface soil as both a potential source and sink of atmospheric MPs, underscoring the need for further research on the regional dynamics of wind-driven MP emissions and their associated ecosystem health risks in semi-arid croplands.