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.
Collection of various Covid-19 face masks of different types and colours from an ocean and terrestrial environment in Hong Kong and Nigeria respectively. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)
Photo credit: OceansAsia (with permission) and Dr. Oluwatoyin Fadare.
