Which among the following has the highest concentration of PAN ?

The photochemical smog result from the action of sunlight on unsaturated hydrocarbon and nitrogen oxides produced by automobiles and large manufacturing factories.

Photochemical smog has high concentration of oxidising agents and therefore called as oxidising smog.

Peroxxyacetyl nitrate $\left(\mathrm{PAN}\right)$ is formed by hydrocarbon in the polluted air it is the example of oxidising smog.