Formation of Photochemical Smog

As we know, photochemical smog is composed primarily of ozone, NOx, and PAN. These species all interact with each other, for example, ozone comes about as a result of the reaction between NOx and VOC. The following schematic shows the relationship between the various species in smog. When looking at the schematic, take special note of the important role that radicals play in the different reactions.

At the bottom of the image, NO and hydrocarbons are released from burning fossil fuels. NO reacts with O3 or RO2 to form NO2, which then absorbs NO and O. The atomic oxygen produced then reacts with O2 to form tropospheric ozone, which continues the reactions with NOx. The following image aims to show a few (not all) of the major reactions involved in the formation of photochemical smog:

Now, lets try a runnable model for photochemical smog formation:

First, read the Background to the model

Next, go to the Runnable Model!!

Quick Quiz: Which of the following elements is not involved in ozone formation?
Carbon Monoxide
Nitrogen Oxide
Oxygen
Sulfur Dioxide

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