Photochemical smog is formed as a result of the reaction of sunlight with hydrocarbonds and nitrogen oxides. Ozone, nitric oxide, acrolein, formaldehyde, and peroxyacetyl nitrate (PAN) are common components of photochemical smog. The formation of photochemical smog can be summarized as follows:
Burining of fossil fuels lead to the emission of hydrocarbonds and nitrogen dioxide in the atmosphere. High concentration of these pollutants in air results in their interaction with sunlight as follows :
`{:(NO_(2(g)), overset(hv) rarr, NO_((g)),+O_((g))),("Nitrogen dioxide",,"Nitric oxide",):}`
`O_((g))+O_(2(g)) harr O_(3(g))`
`O_(3(g))+NO_((g)) rarr NO_(2(g)) +O_(2(g))`
While ozone is toxic in nature, both `NO_(2)` and `O_(3)` are oxidizing agents. They react with the unburnt hydrocarbons in air to produce fromaldehyde , PAN, and acrolein.
`3CH_(4)+2O_(3) rarr underset("Formaldehyde")(3CH_(3)=0)+3H_(2)O`
