Atmospheric Dust Fall And Source Analysis In Hohhot

Ecological environment is fragile in arid and semi-arid areas of north China, where the soil is loose. So it is easy to have dust weather in the condition of windy weather and make the quality of air environment declining. Hohhot in the autonomous region of Inner Mongolia is located at the easy regions of happening sandstorm.The study area is mainly Hohhot in this paper. Set sampling points by the way of glass ball and wet and collect dust samples during 2005-2006 in Inner Mongolia Normal University and the Shengle campus in Helin county. Surface soil samples were collected by the Pacific shovel in the north foot of Yinshan Mountain and Mongolian. Road dust samples, coal dust samples and building dust samples were swept by brush in Hohhot. Mechanical composition, specific surface area, scanning electron microscopy and chemical elements and other physical and chemical experiments were did using the samples.The experimental data were analyzed and compared by the methods of using comparison analysis, discriminant function analysis, enrichment coefficient and so on. It shows that atmospheric dust fall concentrates in the spring in Hohhot, particularly in the windy weather; diameter range of dust fall particle in sand storm days is big in Hohhot and it is in the impact of the specific conditions, the stability of granularity distribution of dust fall is infirm; Dust fall has greater specific surface area, the average specific surface area is 5.65 m2/g in the condition of wet collection and 2.60 m²/g in the condition of glass ball collection; scanning electron microscope displays that the size of dust fall particles in wet collection is smaller with uniform granularity transition and the size of dust fall particles in glass ball collection is larger with big difference of granularity, and the proportion of big particles in dust fall with wet collection is smaller than that with glass ball collection.SiO₂ is the most important composition in all dust fall and its percentage is about 50% in quality, followed by the content of Al₂O₃, between 11% -14% in quality. The difference between the content of CaO and Fe₂O₃ is little and its percentage is about 5% -7% in quality. SiO₂ and Al₂O₃, Fe₂O₃ are the most important components in dust fall. In Hohhot individual components of dust fall in sand storm days are similar to dust fall in non sand storms days as for the chemical composition on the percentage of quality, but the overall difference is big. The relevance is good between the surface soil in the north foot of Yinshan Mountain and the dust fall in Hohhot. Overall, the source of dust fall in urban district of Hohhot is mainly surface soil in the north foot of Yinshan Mountain nearby and road dust in urban areas. The main source of dust fall added other rising substance on the transport path in the process of transmission.Through this research, the quality of dust fall and its main sources have been made clear during the spring and summer in Hohhot basically. And provide a scientific basis for the improvement of the quality of the atmospheric environment in urban.Road dust in urban is a combination of traffic dust, coal soot dust, construction dust and other mixture of a variety of sources. Due to the condition of actual sampling constraints, the composition of road dust may not be able to distinct in detail, but it can show that the representation of traffic dust is high from the having result of experiment. Because of quantitative restrictions of samples, source analysis of dust fall in Hohhot is unable to use the method of factor analysis and the relations between dust fall and surface soil in Mongolia was analyzed rough. It is truly the deficiency of the thesis.