M. Krautstrunk et al., An experimental study on the planetary boundary layer transport of air pollutants over East Germany, ATMOS ENVIR, 34(8), 2000, pp. 1247-1266
The transport of atmospheric pollutants in the planetary boundary layer ove
r East Germany was studied during the SADE-94 experiment using airborne and
ground-based observations of meteorological and chemical parameters. Stron
g jump-like changes of the SO2 and NOx mixing ratios measured at Melpitz, a
rural site about 50 km northeast and 90 km west of two major lignite-coal
mining and industrial areas, demonstrate the influence of high emissions an
d mesoscale transport on the air quality at a rural location. Data of two d
ays with prevailing winds from east and southwest, respectively, were used
to determine the origin of plumes from their characteristic species or thei
r specific trace gas concentration ratios. An attempt has been made to esta
blish emitter-receptor relationships between the emittants and the measured
plumes of SO2 and NOx. It is shown that not only in complex terrain, where
trace gas dispersion is guided in many cases by the terrain structure but
also over flat country sites the trace gases of single-point sources are tr
aceable over distances of more than 100 km in the PBL. Furthermore 75 km do
wnstream the source area surface concentrations of air pollutants caused by
downdrafts are measured, which exceed 25% of the value registered direct i
n the lee of the source. Data of a third day describe the mixing ratio of a
ir pollutants in the convective boundary layer at Melpitz. NOx and SO2 are
used to depict bottom-up and top-down mixing processes mainly in the entrai
nment zone. Under low-wind conditions, neutral or stable PBL and a capping
inversion single air pollution plumes are detectable over long ranges in ti
me (>6 h) and space (>100 km) over flat terrain. The characteristic feature
s of the plumes keep unchanged during transport. So high stacks only displa
ce the problem of near-surface air pollution from the source region to area
s far downstream. (C) 2000 Elsevier Science Ltd. All rights reserved.