In recent years, smog weather has frequently appeared in China, and the air quality problem has aroused great concern of the whole society. The following figure shows four vertical temperature distrib

In recent years, smog weather has frequently appeared in China, and the air quality problem has aroused great concern of the whole society. The following figure shows four vertical temperature distributions. C

Analysis of test questions: One of the conditions for smog formation is inversion weather, which makes atmospheric convection weak and pollutant concentration high. In the figure, ① ② ③ ④ indicates the process from no inversion to inversion generation (② to ③ inversion enhancement) and then inversion disappears. So choose C.