Measurement-based modeling of bromine chemistry in the Dead Sea boundary layer – Part 2: The influence of NO2 on bromine chemistry at mid-latitude areas E. Tas1,2, M. Peleg1, D. U. Pedersen1, V. Matveev1, A. P. Biazar3, and M. Luria1 1Institute of Earth Sciences, Hebrew University of Jerusalem, Israel 2Atmospheric Chemistry Division, MPI for Chemistry, Mainz, Germany 3Earth System Science Center, University of Alabama in Huntsville, Huntsvile, AL 35899 USA
Abstract. Understanding the interaction between anthropogenic air pollution and
Reactive Halogen Species (RHS) activity has had only limited support from
direct field measurements, due to the fact that past field measurements of
RHS have been mainly performed in Polar Regions. The present paper
investigates the interaction between NO2 and Reactive Bromine Species
(RBS) activity by model simulations based on extensive field measurements
performed in the Dead Sea area, as described in a companion paper (Tas et
al., 2006). The Dead Sea is an excellent natural laboratory for this
investigation since elevated mixing ratios of BrO (up to more than 150 pptv)
are frequently observed, while the average levels of NO2 are around
several ppb. The results of the present study show that under the chemical
mechanisms that occur at the Dead Sea, higher levels of NO2 lead to
higher daily average mixing ratios of BrOx. This is the result of an
increase in the rate of the heterogeneous decomposition of BrONO2,
which in turn causes an increase in the rate of the "Bromine Explosion"
mechanism. However, above a certain threshold level of NO2 (daily
average mixing ratios of 0.2 ppbv during RBS activity), the daily average
mixing ratios of BrOx decrease for a further increase in the NO2
mixing ratios. This investigation shows that the influence of NO2 on
BrOx production clearly reflects an enhancement of RBS activity caused
by anthropogenic activity.
Citation: Tas, E., Peleg, M., Pedersen, D. U., Matveev, V., Biazar, A. P., and Luria, M.: Measurement-based modeling of bromine chemistry in the Dead Sea boundary layer – Part 2: The influence of NO2 on bromine chemistry at mid-latitude areas, Atmos. Chem. Phys., 8, 4811-4821, doi:10.5194/acp-8-4811-2008, 2008.