Journal of Earth Science & Climatic Change
Open Access

Abstract

One of the important properties of atmospheric aerosol particles is its density and its morphology. During the Metro Manila Air Quality Characterization Experiment in summer 2015 (MACE 2015), characterization of aerosol particle physical-chemical properties was conducted over the selected sites of Metro Manila. The focus of this study was the particle density and dynamic shape factor. An inversion algorithm for the particle number size distribution in terms of the volume equivalent diameter was used to combine measurements of a mobility and an aerodynamic particle size spectrometer. The merging algorithm was used to derive particle density and dynamic shape factor. This methodology was used to calculate effective densities from both roadside and background sites. The average derived particle density in the roadsides varied from 1.3 g/cm3 to 1.4 g/cm3 while at the background site it was approximately 1.6 g/cm3. In general, the derived dynamic shape factor at the roadside was higher compared to the background site. This suggests that, at the roadside, the dominant aerosol particles are soot agglomerates. At the background environment, particles are a mixture of freshly emitted and aged particles, as well as of secondary particle material. The estimated effective density in the two roadsides was between 1.04 g/cm3 and 0.82 g/cm3 which is lower compared to the background site with a value of 1.25 g/ cm3. This agreed well with previous studies, which showed that the effective density decreases with increasing agglomeration of soot particles. Estimated aerosol particle mass concentration, derived from merged SMPS and APS number size distribution was found to be higher than that measured with a gravimetric method during most of the sampling days. Reasons for this difference are discussed cursorily. These results will be used for mass closure at urban background and roadside sites.

Biography

G A Catipay is a Master of Science in Atmospheric Science in Ateneo de Manila University. She completed her Bachelor’s degree in Physics at Mindanao State University.

Email: grethylcatipay@gmail.com