Smog is a heterogeneous mixture.
Step-by-step explanation:
The mixtures are classified into two type depending upon their uniformity. When the mixture is uniformly distributed, it is called as a homogeneous mixture and when the mixture is spread in a uneven manner, it is called as an heterogeneous mixture. Smog is a chemical reaction which occurs when rays of light reacts with nitrogenous oxides. It is also a type of air pollution.