analysis for ions,e.g., chloride,nitrate,ammonium, and sulfate in the pm10 sample filter was performed using lon chromatography (dionex, dx500 modle)equipped with an analytical column ionpac AS15,eluent source of EG40 with a flow rate of 0.5 ml/min, suppressed conductivity for detection, and an eluent suppressor (ASRS-ULTRA). A quarter of the 20.3 cm x25.5 cm sample filter was cut into small pieces,and then placed into 100 ml conical flask. twenty five milliliters of deionized water was added into the conical flask. the sample was ultrasonically extracted for at least 30 minutes at room temperature to dissolve the ionic comonents.then ,the sample was filtered and analyzed for the ionic content. similarly,the bank filter was subjected to the same experimental procedures. the final concentration of each of the ionic component was calculated taking into consideration of the total effective area 0f the sampled filter , and divided by the total air volumetric flow rate passing through the filter.