# POCP: How many ozone molecules can be created by one ethene molecule?

One ethane molecule can create two molecules of ozone, one ethanol molecule can create one molecule of ozone:

In the following table the POCP is twice as high for ethene than for propane:

From this fact I expect four molecules of ozone from ethene, but in my own formulated reaction mechanism I get only three ozone molecules:

How many ozone molecules can be created by one ethene molecule and if my proposed mechanism is wrong what is the correct one?

I think this question cannot be answered so easily - your proposed reaction mechanism, however, looks good. A detailed explanation and "main reaction mechanism" can be found here, page 192 (just search for "ethene" in the book). As you already indicate ethene reacts with a hydroxyl radical, followed by the addition of oxygen. The reaction with NO generates the HOCH$_2$CH$_2$O radical which can either dissociate or react with another oxygen molecule.

Further reactions of the oxidized products occuring during this pathway can also be found in the above reference, see page 372 (unfortunately only some parts of the book are available for free).

• Thank you for your research you've done. So it makes sense to me that the values are some average values. (If maximally three mols ozone molecules can be created by one mol ethylene I expect to create in average 0.75 mol ozone by one mole ethanole.) – laminin Jun 26 '15 at 21:59
• You're welcome. They do mention that there are different models/mechanisms to estimate/simulate the amount of ozone that will be created on average, but I have never dealt with those (probably an atmospheric chemist needed for that). – snurden Jun 26 '15 at 22:04