Variation of selected air quality indicators over the city of Beirut, Lebanon: Assessment of emission sources

It is well established that the Mediterranean region experiences high pollution episodes as a result of its closed location and hot-humid long summers. However, few long-term field measurements have been conducted along the Eastern Mediterranean coast in general and in Arab countries, in particular. Hence, a six-month field study of major indicators like CO, SO2, PM10 and O3 were conducted in Beirut, Lebanon. Measurements on an upwind site showed that the monthly average concentrations of CO, SO2 and O3 were lower than the USEPA air quality standards while the monthly average concentrations of PM10 were higher. Diurnal variations showed that vehicle-induced emissions contribute significantly to CO levels while winter heaters constitute the major source of SO2. High diurnal and nocturnal levels of PM10 and O3 are the results of several local and long-range transport phenomena.