Fig. 6.
Scanning electron microscopy (SEM) images of the meltblown (a and b) and spunbond (c and d) mask layer after biodegradation in the presence of sewage sludge under room temperature for 4 weeks.
Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.