146
Air Pollution and Turbulence: Modeling and Applications
Reported below is a scheme based on the similarity theory and the micrometeorological variables proposed by Irwin (1983), which is included in several regulatory
models:
2 1/2
L
( )
( , )
y
y
v
v
TF T T
σ = ′
(5.20)
2 1/2
L
(
)
( , )
z
z
w
w
TF T T
σ = ′
(5.21)
with
−
⎡
⎤
= +
⎣
⎦
1
1/2
1 0.9( /1000)
y
F
T
(5.22)
−
⎡
⎤
= +
<
⎣
⎦
1
1/2
1 0.9( /500)
0
z
F
T
L
(5.23)
−
⎡
⎤
= +
>
⎣
⎦
1
0.806
1 0.945( /100)
0
z
F
T
L
(5.24)
TABLE 5.4
Briggs’s Sigma (1973) in the Open Country and
Urban Environment
Pasquill
s y (m)
s z (m)
Urban dispersion parameters* (for distances between 100 and
10,000 m)
A–B
0.32x(1 + 0.0004x) −0.5
0.24x(1 + 0.001x) 0.5
C
0.22x(1 + 0.0004x) −0.5
0.20x
D
0.16x(1 + 0.0004x) −0.5
0.14x(1 + 0.0003x) −0.5
E–F
0.11x(1 + 0.0004x) −0.5
0.08x(1 + 0.00015x) −0.5
Rural dispersion parameters (for distances between 100 and
10,000 m)
A
0.22x(1 + 0.0001x) −0.5
0.20x
B
0.16x(1 + 0.0001x) −0.5
0.12x
C
0.11x(1 + 0.0001x) −0.5
0.08x(1 + 0.0002x) −0.5
D
0.08x(1 + 0.0001x) −0.5
0.06x(1 + 0.0015x) −0.5
E
0.06x(1 + 0.0001x) −0.5
0.03x(1 + 0.0003x) −1.0
F
0.04x(1 + 0.0001x) −0.5
0.016x(1 + 0.0003x) −1.0
* Source: Briggs, G.A., Diffusion estimation for small emissions, in
environmental research laboratories, air resources atmospheric turbulence and diffusion laboratory, Annual report,
1973. USAEC Report ATDL-106, National Oceanic and
Atmospheric Administration, December 1974.
© 2010 by Taylor and Francis Group, LLC