The US and other industrialized countries have relatively good waste management systems. In contrast, trash in low-income countries often accumulates on the streets (which ends up washing to streams and rivers ending in the ocean), or is disposed of in illegal dumping sites (many times open-air), landfills, and open burning.
Of course, even where there are good waste management systems, people have to make use of those systems and dispose of their masks properly—in trash bins—and that doesn’t always happen. I have seen so many photos and videos of masks in rivers and oceans, and of course it’s not sustainable.
Those blue surgical masks are somewhat degradable, but they have a plastic layer. Gloves are plastic. So these things are not going anywhere for many, many years. Over time they just become smaller and smaller particles—and these microplastics were a problem even before the pandemic.
We’re not yet sure what exactly the dangers are of micro and nano-sized plastics in the environment, but high concentrations have been found in fish, water, sediments, soils, and air. Organisms, including humans, are consuming them in food and water, and breathing them in. This is an active area of research to elucidate potential consequences for the environment and humans.
The improper disposal of single-use personal protective equipment has been a big concern for environmental people. So has the overuse of PPE. We don’t need to wear gloves to go to the grocery store. It’s more efficient to just wash your hands with soap and water.