## 2 Materials and Methods
### Boundary-Layer Wind Tunnel Experiments: Resuspension Testing and Calculations  
Resuspension testing was performed at the Aeolian Simulation Laboratory, Benjamin University of the Negev, using a boundary-layer wind tunnel [13]. Untreated and treated soils were tested following either 2 weeks or 6 weeks beginning from the day of treatment. The different times were chosen to represent different periods of aging following an incident. Experiments were conducted under four wind velocities, 5.3, 6.8, 8.1, and 9.6 m s\({}^{-1}\), representing typical natural winds associated with dust emission in this region. PM\({}_{10}\) dust concentrations were recorded by light-scattering laser photometers DustTrak DRX 8534 (TSI Inc., Shoreview, MN, USA) placed 25 cm above the tunnel bed. Before placing the soil trays in the wind tunnel, PM\({}_{10}\) background levels of up to 20 ug m\({}^{-3}\) were recorded. Background levels were subtracted from the PM\({}_{10}\) measurements, which were taken at different wind velocities. Each sample was measured for a duration of 30 s, at 1 s intervals. This short duration is enough to determine the dust emission patterns in controlled experiments [3,5]. Mass flux values of PM\({}_{10}\) resuspended from the ground (g m\({}^{-2}\) s\({}^{-1}\)), expressed as F(PM\({}_{10}\)), were calculated according to the following [13]:  
\[\mathrm{F}(\mathrm{PM}_{10})=\frac{\mathrm{C}(\mathrm{PM}_{10})\times\mathrm{ Vt}}{\mathrm{Ap}\times\mathrm{t}} \tag{1}\]  
where C(PM\({}_{10}\)) is the recorded PM\({}_{10}\) concentration (ug m\({}^{-3}\)), Vt is the air volume in the wind tunnel (3.43 m\({}^{3}\)), Ap is the area of the experimental plot (0.25 m\({}^{2}\)) and t is time (in seconds).  
Mean mass flux values of PM\({}_{10}\) (\(\overline{\mathrm{F}}\)(PM\({}_{10}\))) were calculated by averaging all FPM\({}_{10}\) results per sample, i.e., 30 calculated flux values obtained over 30 s per wind velocity.  
Saltating particles associated with the initiation of the dust emission process from soils [4,5] were collected by traps placed 2.5 to 10.5 cm above the tunnel bed and along the wind direction. Collected particles were weighted at the end of each experiment. Mean mass flux values of saltating particles (g m\({}^{-2}\) s\({}^{-1}\)), expressed as \(\overline{\mathrm{F}}\)(saltation), were calculated according to the following:  
\[\overline{\mathrm{F}}(\mathrm{saltation})=\frac{\mathrm{m}(\mathrm{saltation })}{\mathrm{Ap}\times\mathrm{t}} \tag{2}\]  
where m(saltation) is the measured weight of the saltating particles (g), At is the cross-sectional area of the traps (0.02 m\({}^{-2}\)) and t is time (in seconds).  
Suppression efficiencies (SE) of PM\({}_{10}\) or saltating particles (in percentage) were calculated for each stabilizer and soil type at each wind velocity according to the following:  
\[\mathrm{SE}=\left(1-\frac{\overline{\mathrm{F}}}{\overline{\mathrm{F}}( \mathrm{control})}\right)\times 100 \tag{3}\]  
where \(\overline{\mathrm{F}}\) is the mean mass flux values of PM\({}_{10}\) or saltating particles (see above) and \(\overline{\mathrm{F}}\)(control) is the mean flux of the control sample (untreated) for the same wind velocity and soil type.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Soil** &
\begin{tabular}{c} **Non-Stabilized** \\ **Control (Untreated)** \\ \end{tabular} & **Tap Water** & \multicolumn{4}{c}{**Stabilization Material**} \\ \cline{3-5}  & & **CaCl\({}_{2}\)** & **MgCl\({}_{2}\)** & **Dead Sea Salt** \\ \hline Yamin & A & B & C & C & C \\ Ze\({}^{\prime}\)elim & A & B & C & C & C \\ \hline \hline \end{tabular}  
* Testing of untreated soils;
* Testing of soils 2 weeks post-treatment;
* Testing of soils 2 weeks and 6 weeks post-treatment.  
\end{table}
Table 2: Stabilization experimental matrix.