How has COVID-19 medical face mask altered the dynamics of pollutants from incinerated wastes?

Abstract

The COVID-19 pandemic caused the disposal of an unprecedentedly huge amount of medical face masks, part of which were burnt or incinerated alongside other solid wastes. In this study, we investigated how the presence of the common medical masks may have altered the nature and quantities of pollutants normally associated with the burning of solid wastes. It was found that the addition of increasing amount of face masks (at 1.82%, 3.71% and 5.67% by mass) to solid wastes had no influence on the types of pyrogenic PAHs (polycylic aromatic hydrocarbons) present in the combustion residues. However, presence of the masks at 5.67% led to a drastic reduction in PAHs concentration (∑16PAHs = 0.83 ± 0.047 mg/kg, compared to the concentration measured when the face masks were not incorporated, ∑16PAHs = 4.65 ± 0.23 mg/kg). Mixtures containing 3.71% and 5.67% of masks caused increases in total suspended particulate matter (TPM) by 475.6% and 796.4%, respectively. Presence of the masks at 3.71% and 5.67% also led to emission of poisonous carbon (II) oxide gas above the environmental safe limit of 29 mg/m3. Furthermore, addition of face masks led to higher concentrations of highly toxic metals (As, Cd, Pb and Cu) in the combustion residues of the solid wastes. Overall, this study demonstrates that medical face masks are better incinerated separately, rather than combining them with regular solid wastes. The findings are invaluable for ongoing management of used face masks in health facilities around the world, and in event of any future global or regional pandemic.