The influence of different seasonal monsoon seasons on airborne and marine microplastics at selected stations on the west coast of Peninsular Malaysia

Microplastic (MP) pollution poses a significant environmental threat, particularly as it enters both the atmosphere and the oceans, especially in coastal environments. This is the first study to determine the concentration of MPs in two environmental compartments, the atmosphere and the marine environment on the west coast of Peninsular Malaysia (Port Dickson and Port Klang), across different monsoon seasons. The MPs were extracted using KOH digestion and density separation using ZnCl₂. The quantification of the particles was performed using Nile Red Solution. The results showed the concentrations of MPs in the atmosphere and seawater ranged from 7.16 to 7.62 particles m⁻³ and 156.24 to 221.90 particles L⁻¹, respectively. A significant difference in MP concentrations between sites was observed only in seawater samples, with Port Klang exhibiting higher values. Additionally, airborne samples exhibited significant seasonal variation, with higher MP concentrations recorded during the Northeast monsoon. The observed MPs morphology consisted mostly of fragments (up to 60 %) and fibres (up to 52 %) in the airborne and marine samples, respectively. Additionally, differences in rainfall precipitation and temperature across monsoon seasons significantly impact MP concentrations in marine and airborne samples. The findings highlight the importance of monsoons and coastal activities in influencing MP inputs into the coastal environment, which provides critical insights into MP pollution in the coastal environment.