中文摘要：

以南通某高校为采样点,采集3个校区教学楼不同楼层室内降尘,测试并分析样品的粒度、磁学特征、重金属污染的垂向分布规律,讨论重金属污染影响因素.研究发现,样品的粒度特征在垂向上呈明显波动变化,在人流量大的教学层,粒度特征受教学活动影响;在人流量小的办公层,粒度大小与楼层高度有关,即随楼层增加,粒度逐渐减小,如校区3教学楼1-3、7、9层粒度分别为35.4、29.0、28.8、27.3、23.2μm.室内降尘磁性矿物主要以亚铁磁性矿物和不完整反铁磁性矿物为主,χARM值垂向变化趋势与χlf基本一致,指示单畴颗粒对样品磁化率贡献较大.各校区教学楼不同楼层Cu、Zn、Pb、As元素富集因子（EF）值由10降至接近1,指示随楼层增加重金属元素污染程度从严重污染到无污染;校区3教学楼1—5楼重金属污染程度均相对较高（内梅罗指数平均为20.08）,6层及以上样品重金属污染程度较低（内梅罗指数平均为9.01）,说明随着楼层的增加,重金属污染总体呈降低趋势.小于20μm粒径颗粒对重金属元素As具有较好吸附作用,大于20μm颗粒对重金属元素吸附作用较弱.饱和等温剩磁（SIRM）与重金属元素As具较好的正相关关系（R^2=0.4351）,用SIRM可快速指示室内降尘重金属元素As的污染状况.

英文摘要：

In this study,three college campuses in Nantong,Jiangsu province were chosed as sampling sites. Indoor dust fall samples on different floors of teaching buildings were collected,and vertical distributions of grain size,magnetic properties,and heavy metal contents were analyzed.Then,the factors on heavy metal pollution were discussed. It was found that the grain size of the dust fall changed significantly in the vertical direction. On the teaching floors,where there were large flows of students,the grain size was influenced by the teaching activities. However,on the office floors the distribution of grain size was primarily dependent on the building height,which means the grain size decreased with the height. For example,In campuse 3,the samples＇ grain size on floor1—3,7,9 were respectively 35. 4 μm,29. 0 μm,28. 8 μm,27. 3 μm,23. 2 μm. The magnetic minerals of indoor dust mainly contained ferrimagnetic minerals and incomplete antiferromagnetic minerals. The minerals of single domain（ SD） particles contributed more to samples＇ magnetic susceptibilities than other magnetic minerals. EF values of element Cu,Zn,Pb,As decreased from10 to 1 with the height of floor,and the average Nemerow index value of 1—5 floor（ 20. 08） was higher than the one of 6—9（ 9.01）. These data indicated that heavy metal contents were relativelyhigh from first to fifth floor of the teaching buildings in each campus,and decreased from sixth floor and above. The particulates 20 μm had higher adsorption to the element arsenic than those20 μm. Magnetic properties of saturation isothermal remanent magnetization（ SIRM） had positive correlation with the content of arsenic（ R^2= 0. 4351）,and the parameter SIRM can be used conveniently to indicate the contamination situation of arsenic.