88
Fundamentals of Corrosion
TabLE 4.1
Characteristics of Selected Gaseous Air Constituents
Eq. Conc. (μΜ)
Deposition
Velocity (cm/s)
Deposition Rate
(ng/cm 2 )
Gas
Η
M/atm Outdoor
Indoor Outdoor Indoor Outdoor
Indoor
O 3
1.8
(−2)
2.3 (−4)
1.7 (−4)
0.05–1
0.036
5.8 (−3)
6.8 (−4)
H 2 O 2
2.4
(5)
4.2 (3)
1.2 (3)
—
0.07
—
5.0 (−4)
SO 2
1.4
—
1.1 (−2)
2.9 (−3)
0.1–1.2
0.05
7.5 (−3)
2.7 (−4)
H 2 S
1.5
(−1)
6.1 (−4)
4.0 (−5)
0.38
0.03
2.2 (−3)
1.1 (−5)
NO 2
7.0
(−3)
1.9 (−4)
3.8 (−5)
0.2–0.8
0.006
2.0 (−2)
6.2 (−5)
HNO 3
9.1
(4)
2.9 (2)
2.7 (2)
0.1–30
0.07
1.4 (−2)
5.5 (−4)
NH 3
1.0
(1)
1.1 (−1)
5.8 (−1)
0.3–2.6
0.05
6.6 (−3)
2.1 (−3)
HC1
2.0
(1)
1.5 (−2)
1.9 (−3)
—
0.04
—
5.8 (−6)
Cl 2
6.2
(−2)
1.2 (−6)
1.4 (−7)
1.8–2.1
—
1.1 (–4)
—
HCHO
1.4
(4)
1.1 (2)
1.4 (2)
—
0.005
—
6.3 (−5)
HCOOH
3.7
(3)
3.3 (1)
7.4 (1)
—
0.006
—
2.3 (−4)
Note: The equilibrium solution concentration and deposition rate values were based on correlations from Table 4.3, and using geometric mean values for the intervals, 1.8 (−2) means
1.8 10 −2 .
Source: From Reference 25.
TabLE 4.2
Concentration of Selected Gaseous
Air Constituents
Gas
Concentration (ppb)
Outdoor
Indoor
O 3
4–42
3–30
H 2 O 2
10–30
5
SO 2
1–65
0.3–14
H 2 S
0.7–24
0.1–0.7
NO 2
9–78
1–29
HNO 3
1–10
3
NH 3
7–16
13–259
HCl
0.18–3
0.05–0.18
Cl 2
<0.005–0.08 a
0.001–0.005
HCHO
4–15
10
HCOOH
4–20
20
a Corresponding to 5 wt% HCl.
Source: From Reference 24.