An official website of the United States government
Here's how you know
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.
Comparisons between simulated and observed air concentrations at several stations in Europe. A black rectangle shows the activity observed and the red rectangle the simulated air concentration for the observation period. The red dash represents the simulated hourly concentration.