Air Transport Calculators for PEF

Using the Chemical Transport PEF Tool

PEF - Particulate Emission Factor Wind Driven
PEF_sc - Particulate Emission Factor Mechanically Driven - Unpaved Road Traffic
PEF^'_sc Particulate Emission Factor - Other Construction Activities
PEF_off - Mechanical Particulate Emission Factor for Off-site Receptors (Standard Vehicle Traffic)
PEF^'_off Mechanical Particulate Emission Factor for Off-site Receptors (Other Construction Activities)

Transport Concentrations

Nonradionuclide Equation

Radionuclide Equation

Enter Beginning Soil Concentration

C_s (Nonradionuclide concentration in soil at source) mg/kg

C_s (Radionuclide concentration in soil at source) pCi/g

Resulting Air Concentration - PEF Wind Driven

C_a (Nonradionuclide concentration in air in center of source) mg/m³

C_a (Radionuclide concentration in air in center of source) pCi/m³

Resulting Air Concentration - Mechanical PEF_off for Off-site Receptors (Standard Vehicle Traffic)

C_a (Nonradionuclide concentration in air in center of source) mg/m³

C_a (Radionuclide concentration in air in center of source) pCi/m³

Resulting Air Concentration - PEF_sc Mechanically Driven - Unpaved Road Traffic

C_a (Nonradionuclide concentration in air in center of source) mg/m³

C_a (Radionuclide concentration in air in center of source) pCi/m³

Resulting Air Concentration - PEF`_sc - Other Construction Activities

C_a (Nonradionuclide concentration in air in center of source) mg/m³

C_a (Radionuclide concentration in air in center of source) pCi/m³

Resulting Air Concentration - Mechanical PEF`_off for Off-site Receptors (Other Construction Activity)

C_a (Nonradionuclide concentration in air in center of source) mg/m³

C_a (Radionuclide concentration in air in center of source) pCi/m³

Particulate Emission Factor Wind Driven

City (Climatic Zone) - Selection based on most likely climatic conditions for the site
A_s (acres)
U_m (mean annual wind speed) m/s

U_t (equivalent threshold value)
V (fraction of vegetative cover) unitless

A (PEF Dispersion Constant)
B (PEF Dispersion Constant)
C (PEF Dispersion Constant)

F(x) (function dependent on U_m/U_t) unitless
PEF (particulate emission factor) m³/kg
Q/C_wind (inverse of the ratio of the geometric mean air concentration to the
emission flux at the center of a square source) g/m²-s per kg/m³

NOTES:

The Q/C_wind equation and the dispersion constants A, B and C were taken from Exhibit D-2 of the Supplemental Soil Screening Guidance.
A, B, C = PEF region-specific dispersion constants (unitless)
F(x) values for each city are taken from the Soil Screening Guidance Technical Background Document Appendix D Table 2.

Time Spent on Site

DW_cw (days worked - construction worker) day/wk
EW_cw (weeks worked - construction worker) wk/yr
F_D Unitless Dispersion Correction Factor
ED_cw (exposure duration - construction worker) yr

EF_cw (exposure frequency - construction worker) day/yr
ET_cw (exposure time - construction worker) hr
t_c (overall duration of construction) hours
T_t (overall duration of traffic) s

NOTES:

t_c = ED * EW * 7 days/week * 24 hours/day
T_t = ED * EF * ET * 3600 s/hour
F_D = 0.1852 + (5.3537/t_c) + (-9.6318/t_c²)

Subchronic Particulate Emission Factor Mechanically Driven - Unpaved Road Traffic

PEF_sc Equation

W_R (width of road segment) ft
M_dry (road surface material moisture content under dry, uncontrolled conditions) %
number of cars
number of trucks
tons/car

tons/truck
p (days per year with at least .01" of precipitation) days/year
s (road surface silt content) %
A_s (acres)

L_R (length of road segment) ft
A (Dispersion Constant)
A_R (surface area of contaminated road segment) m²
B (Dispersion Constant)
C (Dispersion Constant)
total number of vehicles

ΣVKT (sum of fleet vehicle km traveled) km
W (mean vehicle weight) tons
distance (road length) km/day
PEF_sc (subchronic particulate emission factor) m³/kg
Q/C_sr (inverse of the ratio of the geometric mean air concentration to the
emission flux along a straight road segment bisecting a square site) g/m²-s per kg/m³

NOTES:

Contact your regional risk assessor for assistance.
When calculating ΣVKT, distance (road length) is calculated by assuming the contaminated area of surface soil (A_s) is a square and that the road divides the square evenly. For example, if A_s is 0.5 acres (A_surf = 2,024 m²), the road length would be the square root of 2,024, or .045 km.
The Q/C_sr equation and dispersion constants A, B and C were taken from Equation E-19 of the Supplemental Soil Screening Guidance.
The PEF equation is Equation E-18 in the Supplemental Soil Screening Guidance.

Subchronic Particulate Emission Factor - Other Construction Activities

PEF`_sc Equation

A_c (acres)
A_c-doz (areal extent of dozing) acres
A_excav (area of excavation site) m²
A_c-grade (areal extent of grading) acres
A_c-till (areal extent of tilling) acres
B_l-doz (dozing blade length) m
B_l-grade (grading blade length) m
M_m-doz (Gravimetric soil moisture content) %
M_m-excav (Gravimetric soil moisture content) %
N_A-dump (number of times soil is dumped)
N_A-till (number of times soil is tilled)

N_A-doz (number of times site was dozed)
N_A-grade (number of times site was graded)
S_doz (dozing speed) kph
S_grade (grading speed) kph
d_excav (average depth of excavation site) m
ρ_soil (In situ soil density) g/cm³ - chemical-specific
s_doz (soil silt content) %
s_till (soil silt content) %
U_m (mean annual wind speed) m/s
U_t (equivalent threshold value) m/s
V (fraction of vegetative cover)

A (Dispersion Constant)
A_surf (areal extent of site) m²
B (Dispersion Constant)
C (Dispersion Constant)
J`_T (g/m²s)
M_doz (dust emitted from dozing operations) g
M_excav (dust emitted from excavation soil dumping) g
M_grade (dust emitted from grading operations) g

M_till (dust emitted from tilling operations) g
M_wind (dust emitted by wind erosion) g
ΣVKT_doz (sum of fleet vehicle km traveled) km
ΣVKT_grade (sum of fleet vehicle km traveled) km
F(x) (function dependant on U_m/U_t derived using Cowherd et al. (1985))
PEF`_sc (subchronic particulate emission factor) m³/kg
Q/C_sa (inverse of the ratio of the geometric mean air concentration to the
emission flux at the center of a square source) g/m²-s per kg/m³

NOTES:

Contact your regional risk assessor for assistance.
The Q/C_sa equation and the dispersion constants A, B and C were taken from Equation E-15 of the Supplemental Soil Screening Guidance.
The PEF equation is from Equation E-26 in the Supplemental Soil Screening Guidance.

Mechanical Particulate Emission Factor for Off-site Receptors (Standard Vehicle Traffic)

number of cars
number of trucks
tons/car
tons/truck
City (Climatic Zone) - Selection based on most likely climatic conditions for the site

p (days per year with at least .01" of precipitation) days/year
A_s (acres)
U_m (mean annual wind speed) m/s
U_t (equivalent threshold value)
V (fraction of vegetative cover) unitless

A (PEF Dispersion Constant)
A_surf (areal extent of site) m²
B (PEF Dispersion Constant)
C (PEF Dispersion Constant)
J_T (g/m²s)
M_road (dust emitted by road traffic) g
M_wind (dust emitted by wind erosion) g

total number of vehicles
ΣVKT (sum of fleet vehicle km traveled) km
W (mean vehicle weight) tons
distance (road length) km/day
F(x) (function dependant on U_m/U_t) unitless
PEF_off (particulate emission factor) m³/kg
Q/C_off (inverse of the ratio of the geometric mean air concentration to the
emission flux at the center of a square source) g/m²-s per kg/m³

NOTES:

The Q/C_off equation and the dispersion constants A, B and C were taken from Exhibit E-5 of the Supplemental Soil Screening Guidance.
The PEF equation is from Equation E-29 in the Supplemental Soil Screening Guidance.

Mechanical Particulate Emission Factor for Off-site Receptors (Other Construction Activities)

A_c (acres)
A_c-doz (areal extent of dozing) acres
A_excav (area of excavation site) m²
A_c-grade (areal extent of grading) acres
A_c-till (areal extent of tilling) acres
B_l-doz (dozing blade length) m
B_l-grade (grading blade length) m
M_m-doz (Gravimetric soil moisture content) %
M_m-excav (Gravimetric soil moisture content) %
N_A-dump (number of times soil is dumped)
N_A-till (number of times soil is tilled)

N_A-doz (number of times site was dozed)
N_A-grade (number of times site was graded)
S_doz (dozing speed) kph
S_grade (grading speed) kph
d_excav (average depth of excavation site) m
ρ_soil (In situ soil density) g/cm³ - chemical-specific
s_doz (soil silt content) %
s_till (soil silt content) %
U_m (mean annual wind speed) m/s
U_t (equivalent threshold value) m/s
V (fraction of vegetative cover)

A (PEF Dispersion Constant)
A_surf (areal extent of site) m²
B (PEF Dispersion Constant)
C (PEF Dispersion Constant)
J`_T (g/m²s)
M_doz (dust emitted from dozing operations) g
M_excav (dust emitted from excavation soil dumping) g
M_grade (dust emitted from grading operations) g

M_till (dust emitted from tilling operations) g
M_wind (dust emitted by wind erosion) g
ΣVKT_doz (sum of fleet vehicle km traveled) km
ΣVKT_grade (sum of fleet vehicle km traveled) km
F(x) (function dependant on U_m/U_t derived using Cowherd et al. (1985))
PEF`_off (particulate emission factor) m³/kg
Q/C_off (inverse of the ratio of the geometric mean air concentration to the
emission flux at the center of a square source) g/m²-s per kg/m³

NOTES:

The Q/C_off equation is from Equation E-29 and the dispersion constants A, B and C were taken from Exhibit E-5 of the Supplemental Soil Screening Guidance.
The PEF equation is from Equation E-25 in the Supplemental Soil Screening Guidance.

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