Chemistry Reference
In-Depth Information
Non-aromatic
HH
C
H
H
HHH
C
C
H
H
H
H
H
CCC
H
C
C
H
H
C
HHH
HH
Propane
Cyclohexane
Aromatic
Naphthalene
Benzo(
a
)pyrene
2
12
1
1
3
11
2
3
10
11
12
1
2
9
10
9
10
4
9
5
3
4
8
7
6
5
4
5
8
8
6
7
6
Te tracene
7
Chrysene
Pyrene
8
9
12
1
2
11
7
10
10
3
4
9
6
1
5
2
8
5
4
3
7
6
Fluoranthene
Coronene
fIgure 9.1
Structures of some hydrocarbons.
9.2 orIgInS and cHemIcaL ProPertIeS
The largest releases of polycyclic aromatic hydrocarbons (PAHs) are due to the
incomplete combustion of organic compounds during the course of industrial pro-
cesses and other human activities. Important sources include the combustion of coal,
crude oil, and natural gas for both industrial and domestic purposes, the use of such
materials in industrial processes (e.g., the smelting of iron ore), the operation of the
internal combustion engine, and the combustion of refuse (see Environmental Health
Criteria 202, 1998). The release of crude oil into the sea by the offshore oil industry
and the wreckage of oil tankers are important sources of PAH in certain areas. Forest
fires, which may or may not be the consequence of human activity, are a significant
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