The correct statement(s) regarding photochemical smog is/are:

The reaction/s involved during the formation of photochemical smog are:

\(1. \space NO_2(g) \rightarrow NO(g) + \stackrel{\cdot}{O(g)}\)

\(2. \stackrel{\cdot}{O(g)} + O_2(g) \rightarrow O_3(g)\)

\(3.\space O_3(g) + NO(g) \rightarrow NO_2(g) + O_2(g)\)

4. All of the above