Encyclopedia of Environmental Science and Engineering, Volume I and II

AIR POLLUTION METEOROLOGY 63

102

102

103

104

101

103 104

4 x 100

2 105

2

5

5

2

5

2

5

102

103

3 x 103

101

100

2

2

5

2

2

5

5

(^2525)
σ^1
, HORIZONTAL DISPERSION COEFFICIENT (m)
σ^2
, VERTICAL DISPERSION COEFFICIENT (m)
DISTANCE FROM SOURCE (m)
A - EXTREMELY UNSTABLE
B - MODERATELY UNSTABLE
C - SLIGHTLY UNSTABLE
D - NEUTRAL
E - SLIGHTLY STABLE
F - MODERATELY STABLE
A B C D E F
A - EXTREMELY UNSTABLE
B - MODERATELY UNSTABLE
C - SLIGHTLY UNSTABLE
D - NEUTRAL
E - SLIGHTLY STABLE
F - MODERATELY STABLE
A B C D E F
FIGURE 4 Pasquill–Gifford scheme for estimating vertical and lateral plume
width as function of downwind distance and meteorological conditions.
C001_005_r03.indd 63C001_005_r03.indd 63 11/18/2005 10:13:38 AM11/18/2005 10:13:38 AM