Environmental Pollution Characteristics of Heavy Metal Elements of PM_(2.5) in Yinchuan

For Yinchuan city,the distribution character and the enrichment factor of 9 heavy metal elements of PM_(2.5) are analyzed during 3 periods of the year,i.e,spring sandstorm season,no-house heating season and house heating season.The heavy metal mass concentrations are different in the 3 periods,for details,the Cu,Ni,Mn,Cr,Fe and Cd mass concentration are the highest in spring sandstorm season;the Zn,Pb and Co mass concentration are the highest in the house heating season.It is severely polluted in these two periods of the year.Heavy metal mass concentration sharply changed with particle diameters,it is noticeable that the poisonous heavy metal was absorbed mainly in PM_(2.5);Zn and Cd mainly came from the source of human activity,and enriched obviously;Pb mainly produced and enriched by coal-burning in the house-heating season.It is obviously that coal-burning made a big contribution for Pb pollution in the atmosphere.