Improved Source Apportionment of Black Carbon-Containing Particles in a Complex Tropical Urban Environment: Insight from a Soot Particle Aerosol Mass Spectrometer

Mutian Ma, Laura-Helena Rivellini, ALEX K.Y. LEE, Environment and Climate Change Canada

     Abstract Number: 376
     Working Group: Source Apportionment

Abstract
Positive matrix factorization (PMF) analysis of aerosol mass spectrometry measurements has been extensively used for source apportionment of ambient organic aerosol (OA), but the interpretation of specific OA sources remains challenging. Due to the unique capability of a soot particle aerosol mass spectrometer (SP-AMS) that can detect black carbon (BC), OA, metals and inorganic aerosol (IA) simultaneously, this work utilizes all these chemical information in the PMF analysis in order to advance our understanding on emission and atmospheric aging of BC-containing particles in Singapore, a highly complex urban environment under the influence of various local and regional anthropogenic emissions.

The PMF analysis of BC and OA coating can identify two primary OA (POA) with large differences in BC content that were dominated by local traffic-related emissions, and two secondary OA (SOA) impacted by local chemistry and/or regional transport. By including metal signals in the PMF analysis, an industrial-influenced OA factor that was strongly associated with Na, V, and Ni can be separated from local traffic emissions. In addition, two biomass burning-influenced OA (BBOA) factors with different degree of oxygenation were clearly identified. While K and Rb were largely associated with the two BBOA-related factors, the more oxidized/aged BBOA component accounted for over 95% of potassium sulfate signals that were likely produced via heterogeneous aging during regional transport. Lastly, the integration of IA into the PMF analysis can further provide insight into how SOA formation might be associated with inorganic nitrate and sulfate formation chemistry.