Heavy Metals Contamination withi

Heavy Metals Contamination within Street Dusts

Differential Modeling Equation

A mathematical model was adapted from recent literature¹ that tries to approximate the amount of street dust that will collect within an with a wind blowing over it and a height difference. This model works very well for our study because we are interested in the street dust that collects within a street gutter that has an average height of six (6) inches.

The parameters of the model include the height difference of the depositional area and the area where the wind is blowing, the wind speed, dust concentration within the air, and a constant. Therefore, running this model with local dust concentration data, we can measure the actual amounts being found within the street gutters and make the following assumption:

If the material found within the gutter is more than what is predicted in the model, we can assume that the excess material is coming from other sources such as storm water runoff, and mechanical breakdown on vehicular parts.

The model is shown below with all values being converted into SI units and using air born particulate dust concentrations from the TECQ. The model can also be accessed in MS Excel in order to change the values by Clicking Here.

Simulation Model for Street Dust Deposition

F- Dust Deposition Flux
K- Constant
u*- Friction Velocity
C- Concentration
z-Height

F=ku*z(dC/dz)

El Paso Assumed Wind Speed- 268 cm/s


Assumed Parameters for PM(10)
		PM(10)	Street Dust Flux	0.004882896
k	0.4	PM(2.5)	Street Dust Flux	0.001152144
u*	18
z	0.5	Units- g/m²s
dz	15.24
dC	0.000089

Assumed Parameters for PM(2.5)
k	0.4
u*	18
z	0.5
dz	15.24
dC	0.000021

Model Equation and Parameters Adapted From:
1. GOOSSENS, DIRK , "Quantification of the dry aeolian deposition of dust on horizontal surfaces: an experimental comparison of theory and measurements." Sedimentology 52(2005): 859–873.