Frequency and extent of bromine oxide formation over the Dead Sea

A study has been performed in an attempt to better understand and characterize BrO formation in the Dead Sea region. The DOAS technique was employed to quantify BrO levels at three sites along the Dead Sea representing three different Br^- and pH levels of the water. In order to characterize the spatial extent of BrO formation, measurements were performed at a site south of the Dead Sea itself and also at a site 400 m above the water level. Additionally, measurements were concurrently performed for ozone, nitrogen oxides and meteorological parameters at each of the campaign sites. The results showed that BrO was produced everywhere in the Dead Sea region up to maximum levels of around 200 ppt. The frequency and intensity of BrO production was more intense in the southern part of the Dead Sea corresponding to the increased acidity and bromide content of the water and increased solid salt depositions. Maximum BrO production during the winter was similar to that of BrO produced during summer. BrO was also observed at 4 km inland from the Dead Sea shores and at heights 400 m above the water. However, these levels were less than half the concentration measured at the water level. While it would appear that the Br^- content and pH of the Dead Sea water are the two major factors responsible for the elevated BrO levels observed at the Dead Sea, the presence of NO₂, up to levels of several parts per billion, might also play an important role in the BrO production. Additional factors influencing BrO production could be the extensive salt deposition at the Dead Sea as well as the high sulfate aerosol levels present in the region.