| Summary: | 碩士 === 國立中興大學 === 環境工程學系 === 92 === Abstract
The purpose of this work is to apply a CMB receptor model and the mass reconstruction empirical formulas to estimate the source contributions to ambient aerosol particles. The particles were sampled during the episodic events at NCHU sampling station at Taichung from January 2002 to April 2003. The episodic events were grouped into three categories: biomass burning episodes (N=2), Asian dust storm events (N=10) and a general PM10 episode (N=1). In these events, PM2.5 and PM2.5-10 were collected during daytime and nighttime by using Dichotomous samplers. The samples were further analyzed for water soluble ions, elemental carbon, organic carbon and the metallic elements.
The results obtained from CMB receptor modeling showed that the pollution sources of PM2.5 during the biomass burning event included biomass burning (48.6%), vehicle exhaust (35.6%), nitrate (8.4%), ammonium sulfate (5.1%), marine spray (0.5%) and power plant (0.1%). However, during the non-biomass burning periods (N=8), the sources were vehicle exhaust (48.8%), ammonium sulfate (26.7%), biomass burning (22%), nitrate (6.9%) and power plant (0.9%). It clearly showed that the contribution from the biomass burning was the most significant pollution source during the event. The sources of PM2.5-10 during Asian dust storm events were geological material (44.8%), vehicle exhaust (29.8%), nitrate (7.9%), marine spray (5.8%) and ammonium sulfate (4.1%). Furthermore, there were approximately 83% of the geological material contributing from the dust-storm. The source apportionments of PM2.5-10 during the general PM10 episode were vehicle exhaust (42.3%), nitrate (19.2%), marine spray (15.9%), geological material (14.4%), and ammonium sulfate (12.6%). But the sources for PM2.5 were different, which included vehicle exhaust (36.3%), ammonium sulfate (28.7%), nitrate (16.2%) and power plant (0.5%). The results also showed that the secondary aerosol and the marine spray were the major sources for the general PM10 episodic event.
An additional method of mass reconstruction was used to estimate the source contributions from the geological material (Al, Si, Ca, Ti, Fe, Mg, N and K), marine spray (Na+), ammonium sulfate (SO42-) and nitrate (NO3-). The results showed that a good correlation (R2 = 0.85~0.99) was found between the estimation by using the Chan’s empirical formula and the result obtained from the CMB modeling. Therefore it is reasonable to conclude that the source contributions of the ambient aerosol particles sampled at Taichung can be estimated by using the mass reconstruction method.
|
|---|
