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.
In-vehicle measurements of (A) PN concentrations (B) number-based particle size distributions, in freeways and urban areas in Los Angeles, CA. PIU, particle instrumentation unit, located at the southern California Supersite in downtown Los Angeles. Long Beach and Pasadena are two other urban areas in Los Angeles. Arrows indicate when the vehicle was off road at these three urban locations. From Westerdahl et al. (2005). Copyright 2005, with permission from Elsevier.
