ABSTRACT
Christian Langebartels, Martina Schraudner, Werner Heller, Dieter Ernst and Heinrich Sandermann Jr.
INTRODUCTION: AIR POLLUTANTS AND ELEVATED UV-B RADIATION AS FACTORS OF GLOBAL CLIMATE CHANGE
Apparent changes in the levels of air pollutants and of ultraviolet (UV) radiation in the UV-B range (280-315 nm) at the earth’s surface are components of the widely discussed “global changes”. Thinning of the stratospheric ozone layer is projected to increase UV radiation reaching the terrestrial surface (Kerr and McElroy, 1993; Madronich et al., 1998). On the other hand, tropospheric ozone increased over the past years because of the release of precursor substances such as NO2 and hydrocarbons by human activities (Stockwell et al., 1997; Kley et al., 1999). Recent models predict that ozone and UV-B radiation will simultaneously increase in the troposphere in the future (for a review, see Runeckles and Krupa 1994; Kley et al., 1999). At present, both stresses occur in combination at elevated sites, e.g. mountains of Central Europe and North America.
