The weather system formed by smog and why the visibility in suburbs is lower than that in the city center.

Test answer: 1. B2。 B3。 D test analysis: test analysis: 1. Looking at the map, we can see that the peak of PM 2.5 appears at 8 o'clock and 19 o'clock respectively, which are the peak hours of commuting in the morning and evening. During this time, there were many cars driving on the road and many wastes emitted by cars, which led to the peak of PM 2.5. 2. The wind is small, the atmosphere is relatively stable, the air mobility is poor, and the tiny particles in the air gather and float in the air, forming haze weather. When the air pressure is low, the updraft prevails in the center, and the polluted air is easy to spread; When the front crosses the border, the pressure gradient on both sides is relatively large, and the wind force is relatively large, so the polluted air is easy to spread. When the front is affected by low pressure, there is more rainfall and less dust in the air after rain, so it is not easy to form haze weather, so ① ③ it is not easy to form haze weather when it is affected; When the anticyclone is controlled, the downward flow prevails in the center, and the dust is not easy to spread. When the temperature increases with the height, it is not conducive to the convective movement of air, and the polluted air is not easy to spread. The weather they control is sunny, so the weather system is prone to smog weather. 3. During the foggy day, the solar radiation weakens and the maximum temperature decreases; At night, the atmospheric inverse radiation increases, the minimum temperature rises, and the temperature difference between day and night in cities decreases; In foggy weather, the temperature difference between day and night becomes smaller, the temperature difference between up and down becomes smaller, and even the inversion phenomenon appears, and the thermal circulation weakens; The time described in b and d is early morning, and the fog mentioned in the composite material is related to the relative humidity of the air. Compared with the urban area, the temperature in the suburbs is lower, the air can hold less water vapor and the relative humidity is higher, so the water vapor is easy to condense, there will be more fog and the visibility is low. Test center: This topic examines the road to sustainable development, atmospheric heating process, common weather systems and other knowledge points.