Urban Aerosol Particle Size Characterization in Eastern Mediterranean Conditions

Characterization of urban particle number size distribution (PNSD) has been rarely reported/performed in the Middle East. Therefore, we aimed at characterizing the PNSD (0.01-10 mu m) in Amman as an example for an urban Middle Eastern environment. The daily mean submicron particle number concentration (PNSub) was 6.5 x 10(3)-7.7 x 10(4) cm(-3) and the monthly mean coarse mode particle number concentration (PNCoarse) was 0.9-3.8 cm(-3) and both had distinguished seasonal variation. The PNSub also had a clear diurnal and weekly cycle with higher concentrations on workdays (Sunday-Thursday; over 3.3 x 10(4) cm(-3)) than on weekends (below 2.7 x 10(4) cm(-3)). The PNSub constitute of 93% ultrafine fraction (diameter