Results from a previous USAID sponsored Israeli/Palestinian/US study indicated that emissions from the highly populated and industrialized Israel-Gaza coast are transported inland and lead to elevated levels of ozone over Jordan. In order to determine the magnitude and extent of this transboundary transport of pollutants, a follow-on study involving Jordanian, Israeli, and US scientists was undertaken. The first phase of this work sought to characterize the brown cloud observed over the Red Sea. During an intensive measurement study performed in November 2007, fixed ambient air quality stations measuring ozone and other trace gases, along with meteorological parameters, were located on the Jordanian side of the border in Aqaba and on the Israeli side of the border in Eilat. DOAS measurements of “true” NO2 and NO3 were also made between the two cities. Initial results indicate the pollution episodes are highly dependent on wind direction. Southerly winds carry local transportation (i.e., ship, trucks) and possibly some industrial emissions towards the north end of the Red Sea, while northerly winds are associated with the transport of regional ozone. Elevated NO levels due to local mobile sources were observed during rush hour periods. High NO levels also lead to a titration of NO3 and ozone. Future work will involve determination of pollutant fluxes, identifying important sinks and reactions of NO3, and extending the field measurements to other areas of Jordan and Israel.