PM 10 was collected by a stacked filter air sampler. The elemental contents were analyzed by proton induced X-ray emission (PIXE). The PM 10 solution was instilled every other day to SD mouse’ s lung for one month. The sterile physiological saline was used as the control. One month later

histopathology of the lung tissue was studied and the elemental distributions were analyzed by Scanning Proton Microprobe (SPM). The particle instilled mouse’ s lungs showed measurable inflammation

and the contents of metal binding protein (albumin etc.) in BALF were significantly higher than those of controls. The Ca and Zn contents in tissues were significantly lower than those of controls

while Fe content of PM 10 instilled mice were significantly higher than that of controls. The increased Fe content in pneumonic tissue was duo to the unsoluble Fe compounds (from PM 10 ) remaining in lung tissue which were observed by SPM. The decreased Zn and Ca contents in pneumonic tissue were duo to the progress of pneumonia. The unsoluble Zn and Ca in lung tissue may be extracted by some enzymes and then changed to soluble in the progress of pneumonia. It is suggested that the Zn and Ca efflux from lung tissue may be a way of damaging lung.