Fig. 5.
Population and total area covered by different annual PM2.5 ambient air quality standards worldwide
PM2.5: mass concentration of aerosol particles smaller than approximately 2.5 μm.
Source: World Population Review, 2019.7
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.