BTEX, Nitrogen oxides, Ammonia and Ozone Concentrations at Traffic Influenced and Background Urban Sites in an Arid Environment (poster)

Spatial distribution of key air pollutants were studied in Doha, Qatar in two monitoring campaigns. Time-weighted averages of BTEX components (benzene, toluene, ethyl-benzene, m/p-xylene and o-xylene), as well as NO, NO2, NH3 and O3 were measured from February 29 to March 31, 2016 in two periods at 15 locations. The average NOX concentration slightly exceeded the annual limit value (108 ?g m-3 vs. 100 ?g m-3) and the exceedances were significant at locations highly influenced by traffic emission. Opposite behavior was found for O3 concentration having the highest level at background locations (ranging from 36 to 71 ?g m-3) and the lowest at the most polluted sites (12-30 ?g m-3). The average BTEX concentration was 15.3 ?g m-3, peaking at 40.5 ?g m-3 at the most polluted location. Average concentrations of benzene, toluene, ethyl-benzene, (m+p)- xylene and o-xylene were 1.5, 4.7, 2.0, 5.0, and 2.3 ?g m-3 respectively. Results indicate the dominancy of vehicle emission in the formation of the city's air quality. Atmospheric modification of the components via photochemical reactions was found to be important.