Trans-boundary transport of ozone from the Eastern Mediterranean Coast

As part of an ongoing USAID MERC research program investigating the transport of pollutants in the Eastern Mediterranean region, a joint coordinated campaign involving scientists from Jordan and Israel took place for a three-week period in June 2009. The study was aimed at examining previous modeling results that indicated the presence of elevated ozone levels occurring in Northern Jordan, due to emissions originating in coastal Northern Israel that were transported distances of more than 100 km. In the present investigation, ozone and other pollutants were monitored at five sites in Israel and two in Jordan. The sites were located along the prevailing wind direction that tends to move air-masses eastward from the Mediterranean coast, over the Israel Valley toward the Jordan Valley, and then into Northern Jordan. Analysis of the measurements showed that air masses arriving in Jordan passed over the Israeli metropolitan coastal region, entrapping large amounts of pollutant precursors before transporting them towards Jordan under the predominately westerly wind flows causing peak maximum ozone levels of around 100 ppbv. The present findings confirmed the previous modeling results that indicated higher NOx background levels for the inland stations, peak O3 values at later hours depending on wind speed and distance from the Mediterranean coast and maximum O3 levels over northern Jordan.

► Inland areas of Israel and Jordan are strongly affected by elevated O3 levels. ► Emissions from Israel contribute significantly to photochemical pollution in Jordan. ► Maximum O3 levels observed over northern Jordan validated previous model results.