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.
Quotient of UVVitD/UVEry (A) as a function of the solar zenith angle and (B) as a function of solar UVI data from 2007, at an ozone layer thickness of 250 Dobson units. (C) Solar UVI as a function of the solar zenith angle between January and July 2007. UVVitD, vitamin D UV irradiation; UVEry, erythemal UV irradiance; UVI, ultraviolet index.
