COVID-19 Face Masks as a Long-Term Source of Microplastics in Recycled Urban Green Waste

Abstract

Following the outbreak of the COVID-19 pandemic in March 2020, many governments recommended or mandated the wearing of fitted face masks to limit the transmission of the SARS-CoV-2 virus via aerosols. Concomitant with the extensive use of non-sterile, surgical-type single-use face masks (SUM) was an increase of such masks, either lost or discarded, in various environmental settings. With their low tensile strength, the spunbond and melt-blown fabrics of the SUM are prone to shredding into small pieces when impacted by lawn cutting equipment. Observations highlight the absence of smaller pieces, which are either wind-dispersed or collected by the mower’s leaf catcher and disposed together with the green waste and then enter the municipal waste stream. As proof-of-concept, experiments using a domestic lawn-mower with different height settings and different grass heights, show that 75% of all pieces of SUM fabric caught in the catcher belonged to sizes below 10 mm2, which under the influence of UV light will decay into microfibers. The implications of SUM generated microplastics are discussed.

Environmental Decay of Single Use Surgical Face Masks as an Agent of Plastic Micro-Fiber Pollution

“…Many of the masks encountered in urban greenspaces and roadside verges originated on curbside parking and would have been blown to the locations by the wind as well as by vehicular draught. While most masks discarded/lost on roads and in carparks would eventually be removed by street cleaners, masks deposited in greenspaces remained in situ unless they were caught during mowing operations [9]. Once in the environment, the masks underwent processes of environmental decay.…”

“…The majority of masks were encountered in carparks and at curbside parking locations where they were lost or discarded while entering or exiting parked vehicles. While the majority of these masks were removed during street cleaning operations, a significant quantity of masks was found in urban green spaces, in particular, on the verges of roads and footpaths, where they entered the green waste stream through mowing [9] or decayed in place. Decaying single use facemasks shed large amounts of microfibers into the environment as their bonds break.…”

Indirect effects of COVID-19 on the environment: How plastic contamination from disposable surgical masks affect early development of plants

“…Single use PP masks are usually made of three fabric layers: (a) the outer water-repellent layer (spun bound, non-woven fabric) that provides mechanical strength and protection; (b) middle layer (also a non-woven, melt-blown fabric with high porosity for breathability) that intercepts water droplets; (c) the inner layer (soft fibers by filament spinning and thermal bonding) that is similar to the outer one. The edges are made of heat-wielded seams with two elastic ear loops (Dutton 2008; Spennemann 2022 ; Fadare and Okoffo 2020 ).…”

“…A recent study showed that PP masks released into the urban environment are relatively easily fragmented into smaller pieces due to various physical effects ( e.g. lawn cutting equipment) ( Spennemann 2022 ). Since disposable PP masks are made of fibers ( Aragaw 2020 ), they release secondary MPs into the environment at a much higher rate than plastic boxes or bags due to heat or solar radiation ( Ma et al, 2021 , Shen et al, 2021 ).…”

“…In the environment, plastics are fragmented into macro (>2,5 cm), micro (<5 mm)- and nano-plastics (<100 nm or <1000 nm) via various physical, chemical, and biological processes ( Gigault et al, 2018 , Ng et al, 2018 ). Recently, the environmental hazards of these fragments (especially MPs) has been further amplified by the COVID-19 pandemic due to excessive usage of disposable surgical masks, which inevitably turns into an environmental pollutant ( Shen et al, 2021 , Spennemann, 2022 ). Investigating the microfiber emission from single-use tri-layer masks, Rathinamoorthy and Balasaraswathi (2022) revealed that (a) dry masks released a higher amount of microfibers than wet ones, (b) seawater degraded the masks at a higher rate than freshwater, and (c) weathered masks seem to shed more microfibers than new masks.…”