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Appendix 7
Potential to Create Ozone
Photochemically values relative to ethylene
Ground level ozone is a
precursor of tropospheric ozone. Ozone formation is implicated in respiratory problems and
ecological damage to plants.
Releases to air of
volatile organic compounds (VOC's) can be compared on the basis of their potential to
create ozone photochemically (POCP) relative to ethylene 1.
The potential impact for
a substance is tonne/year released, multiplied by its POCP. The units are tonne/y of
ethylene equivalent.
Substance |
POCP |
| Alkanes |
| methane |
3.4 |
| Ethane |
14.0 |
| Propane |
41.1 |
| n-Butane |
59.9 |
| i-Butane |
42.6 |
| n-Pentane |
62.4 |
| i-Pentane |
59.8 |
| n-Hexane |
64.8 |
| 2-Methylpentane |
77.8 |
| 3-Methylpentane |
66.1 |
| 2,2-Dimethylbutane |
32.1 |
| 2,3-Dimethylbutane |
94.3 |
| n-Heptane |
77.0 |
| 2-Methylhexane |
71.9 |
| 3-Methylhexane |
73.0 |
| n-Octane |
68.2 |
| 2-Methylheptane |
69.4 |
| n-Nonane |
69.3 |
| 2-Methyloctane |
70.6 |
| n-Decane |
68.0 |
| 2-Methylnonane |
65.7 |
| n-Undecane |
61.6 |
| n-Dodecane |
57.7 |
| Cyclohexane |
59.5 |
| Methyl cyclohexane |
73.2 |
| Alkenes |
| Ethylene |
100.0 |
| Propylene |
107.9 |
| 1-Butene |
113.2 |
| 2-Butene |
99.3 |
| 2-Pentene |
95.3 |
| 1-Pentene |
104.1 |
| 2-Methylbut-1-ene |
83.0 |
| 3-Methylbut-1-ene |
118.4 |
| 2-Methylbut-2-ene |
77.1 |
| Butylene |
70.3 |
| Isoprene |
117.8 |
| Styrene |
7.7 |
| Alkynes |
| Acetylene |
28.0 |
| Aromatics |
| Benzene |
33.4 |
| Toluene |
77.1 |
| o-Xylene |
83.1 |
| m-Xylene |
108.8 |
| p-Xylene |
94.8 |
| Ethylbenzene |
80.8 |
| n-Propylbenzene |
71.3 |
| i-Propylbenzene |
74.4 |
| 1,2,3-Trimethylbenzene |
124.5 |
| 1,2,4-Trimethylbenzene |
132.4 |
| 1,3,5-Trimethylbenzene |
129.9 |
| o-Ethyltoluene |
84.6 |
| m-Ethyltoluene |
98.5 |
| p-Ethyltoluene |
93.5 |
| 3,5-Dimethylethylbenzene |
124.2 |
| 3,5-Diethyltoluene |
119.5 |
| Aldehydes |
| Formaldehyde |
55.4 |
| Acetaldehyde |
65.0 |
| Propionaldehyde |
75.5 |
| Butyraldehyde |
77.0 |
| i-Butyraldehyde |
85.5 |
| Valeraldehyde |
88.7 |
| Benzaldehyde |
- 5.6 |
| Ketones |
| Acetone |
18.2 |
| Methylethylketone |
51.1 |
| Methyl-i-butylketone |
84.3 |
| Cyclohexanone |
52.9 |
| Alcohols |
| Methyl acohol |
20.5 |
| Ethyl alcohol |
44.6 |
| i-Propanol |
21.6 |
| n-Butanol |
62.8 |
| i-Butanol |
59.1 |
| s-Butanol |
46.8 |
| t-Butanol |
19.1 |
| Diacetone alcohol |
61.7 |
| Cyclohexanol |
62.2 |
| Esters |
| Methyl acetate |
4.6 |
| Ethyl acetate |
32.8 |
| n-Propyl acetate |
48.1 |
| i-Propyl acetate |
29.1 |
| n-Butyl acetate |
51.1 |
| s-Butyl acetate |
45.2 |
| Organic acids |
| Formic acid |
0.3 |
| Acetic acid |
15.6 |
| Propionic acid |
3.5 |
| Ethers |
| Butyl glycol |
62.9 |
| Propylene glycol methyl
ether |
51.8 |
| Dimethyl ether |
26.3 |
| Methyl-t-butyl ether |
26.8 |
| Halocarbons |
| Methyl chloride |
3.5 |
| Methylene chloride |
3.1 |
| Methylchloroform |
0.2 |
| Tetrachloroethylene |
3.5 |
| Trichloroethylene |
7.5 |
| Vinyl chloride |
27.2 |
| 1,1-Dichloroethylene |
23.2 |
| cis
1,2-Dichloroethylene |
17.2 |
| trans
1,2-Dichloroethylene |
10.1 |
| Other pollutants |
| Nitric oxide |
- 42.7 |
| Nitrogen dioxide |
2.8 |
| Sulphur dioxide |
4.8 |
| Carbon monoxide |
2.7 |
_________________________
- Derwent, R G, M E Jenkin
and S M Saunders; Photochemical ozone creation potentials for a large number of reactive
hydrocarbons under European conditions, Atmospheric Environment Vol 30 No 2, 181-199,
Elsevier Science Ltd (1996).
Revised data have been issued since. Reference : Derwent, R G, M E Jenkin, S M Saunders
and M J Pilling; Photochemical ozone creation potentials for organic compounds in
Northwest Europe calculated with a master chemical mechanism, Atmospheric Environment Vol
32 No 14/15, 2429-2441, Elsevier Science Ltd (1998).
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