Spatial Variations of Particulate Matter in Mid-West Jordan

Abstract

We evaluated aerosol concentrations in the northwestern region of Jordan (Amman, Salt, Madaba, Tafila, and Karak) using a simple mobile aerosol measurement setup during April 2022. The submicron particle number (PN₁) concentration was highest in Amman (4.6×10⁴ m^–3) and lowest in Karak (2.0×10⁴ cm^–3). The main roads connecting these cities exhibited PN₁ between 1.5×10⁴ cm^–3 and 6.6×10³ cm^–3. The mean micron particle number (PM_10-1) concentration varied between 2 cm^–3 and 5 cm^–3 on roads and from 3 cm^–3 to 5 cm^–3 in cities. Micron particulate mass (PM_10-1) concentrations were higher in cities than on main roads, except for Amman-to-Karak road through Madaba, (~128 µg m^–3). Amman had the lowest PM_10-1 concentrations (~34 µg m^–3). The average concentrations of PM_2.5 decreased as we moved southward from Amman. The outcomes of this study suggest that traffic emissions are the main sources of aerosols in cities. The southernmost locations (i.e. Karak) were mainly affected by dust aerosols due to local sand re-suspension from desert areas. As a recommendation, long-term aerosol measurements at multiple sites throughout the country, along with more extensive and repeated mobile measurements, are needed.