COVID lockdown significantly impacted microplastic bulk atmospheric deposition rates

Area of Science:

• Environmental Science
• Atmospheric Chemistry
• Polymer Science

Background:

• Microplastics are pervasive environmental contaminants.
• Atmospheric deposition is a key pathway for microplastic transport.
• Understanding human activity's impact on microplastic pollution is crucial.

Purpose of the Study:

• To compare atmospheric microplastic deposition rates before and during a national lockdown.
• To investigate the influence of reduced human activity on microplastic deposition.
• To identify dominant microplastic polymers in atmospheric deposition.

Main Methods:

• Bulk atmospheric deposition was collected from a vegetated roof in Greater Paris.
• Microplastics were analyzed using micro-Fourier-transform infrared (micro-FTIR) imaging.
• Deposition data from lockdown (spring 2020) was compared to a normal activity period (spring 2021).

Main Results:

• Overall microplastic deposition rates were significantly lower during lockdown (median 5.4 MP m⁻² d⁻¹) compared to normal activity (median 29.2 MP m⁻² d⁻¹).
• This reduction was not observed for the smallest microplastic size fraction.
• Polypropylene (PP), polyethylene (PE), and polystyrene (PS) were the dominant polymers identified.

Conclusions:

• Reduced human activity during lockdown directly correlates with decreased atmospheric microplastic deposition.
• Atmospheric microplastic deposition is highly sensitive to anthropogenic influences.
• This study offers novel insights into the immediate environmental impact of human activities on microplastics.