Answer to Question 1
C
Answer to Question 2
At night when a radiation inversion exists, pollutants are trapped in a smaller volume below the inversion. As the sun rises and the surface warms, the radiation inversion normally weakens and disappears before noon. By afternoon, the atmosphere is sufficiently unstable so that, with adequate winds, pollutants are able to disperse vertically. The changing atmospheric stability, from stable in the early morning to conditionally unstable in the afternoon, can have a profound effect on the daily concentrations of pollution in certain regions. Therefore, pollutant levels can be considerably higher in the early morning than in the early afternoon.