Excuse me, which floor of 3 1 is the grey building? My son has asthma, and air quality is very important. Please help me. Thank you! (Xiaogan, Hubei)

The existence of smoke layer means: "Due to the influence of airflow and building microenvironment, the dust concentration in some buildings is high in a certain height range." But it is not necessarily the 9 to 1 1 floor of a high-rise building, because "its specific height is influenced by many factors, and it is different in different regions, cities, urban areas and even different communities, and it is related to dust density, surrounding building height and airflow turbulence characteristics". This means that the "fly ash layer" of different buildings is different and cannot be generalized. At the same time, because there are too many scientific factors that need to be integrated, the people are also confused. Physics experts pointed out that the statement that 10 layer is a "dust layer" does not conform to the common sense of atmospheric physics. Because at a height of 30 to 40 meters above the ground, the dust will not stop. Dust will not stop in the stratosphere from the ground 10 km to 52 km. In other words, there is no such thing as lime layer in ordinary high-rise buildings. Lime layer is just a statement, which has not been scientifically determined. Under normal circumstances, pollutants in the air are constantly settling and flowing with the airflow. When there is no pollution source in the air, the higher the floor, the cleaner the air. The so-called "dirty air pause" may refer to the so-called "inversion layer" phenomenon. The higher the height of the atmosphere, the lower the temperature, and the air is easy to convection, so that pollutants can spread. However, in autumn and winter and under special climatic conditions, the temperature may increase with the increase of height, and an "inversion layer" will appear in the atmosphere. The thickness of inversion layer varies from tens of meters to hundreds of meters, like a thick quilt covering the city, which hinders the spread of urban pollutants. However, the height of inversion layer changes, and the distribution of pollutants under inversion layer conditions also changes, and will not stay at a fixed height. Therefore, it is not accurate to judge the "grey layer" only by height.