Measurements of Outgassing from PM_2.5 Collected in Xi'an, China Through Soft X-Ray-Radiolysis

PM_2.5 is an important global air pollution issue. PM_2.5 causes various problems on the environment and human health. Even though PM_2.5 of the outdoor air is eliminated by particulate air filters, the chemicals adsorbed on the filtered PM_2.5 can be outgassed and introduced into the semiconductor manufacturing facilities and processes, thus causing defects on the semiconductor chips by producing particles and haze as airborne molecular contamination. Therefore, estimating the amount of the outgassing from PM_2.5 is a very important factor to control gaseous contaminants in the semiconductor industry. In this paper, the PM_2.5 samples at different PM_2.5 mass loadings were collected in Xi'an, China and evaluated using the soft X-ray radiolysis method for determining the relation between the outgassing and the PM_2.5 mass loading. The PM_2.5 samples were also analyzed by several methods for quantifying organic and elemental carbons, water soluble ions, and organic compounds in the PM_2.5 samples. The outgassing measured by the soft X-ray method increased linearly with the PM_2.5 mass loading, and the chemical analyses explained that the organic carbon (OC) was dominantly detected by the soft X-ray method in the current study. Moreover, the sampling location of the PM_2.5 affected on the organic compounds of the PM_2.5.