Explanation:

- Statement 1: Smog is indeed produced by a set of complex photochemical reactions. These reactions typically involve sunlight acting on pollutants like nitrogen oxides and volatile organic compounds in the atmosphere. So, this statement is correct.

- Statement 2: Weather and geography do affect smog. Geographic features like mountains can trap air pollutants, and weather conditions like wind, temperature, and sunlight can influence its formation and dispersal. Therefore, this statement is incorrect.

- Option 1: 1 only is correct because only the first statement is true.

- Option 2, 2 only: Incorrect because the second statement is wrong.

- Option 3, Both: Incorrect due to the false second statement.

- Option 4, None: Incorrect because the first statement is true.

Option 1 - 1 only is the correct choice.