Fig. 6.
Top plots show the frequency distribution of observed wind direction. Bottom plots show box-and-whisker plots of the number concentration of 2.5–10 nm particles. Left: PB event days, right: regular days.
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.