Preliminary Assessment of Morphology and Elemental Composition of Fine Particulates in Selected Urban Areas of Java Island

Abstract

Rapid urbanization and high population density in three major cities in Indonesia, Bandung, Jakarta, and Tangerang have led to significant air quality issues. Fine inhalable particles (PM2.5) with distinct morphologies and elemental compositions pose considerable health risks. This study evaluates the morphology and chemical composition of PM2.5 in these urban areas on Java Island. PM2.5 samples were collected for 24-hour periods using a Teflon filter with the Super Speciation-Air Sampling System (SuperSASS) following the EPA sampling schedule, from May to September 2022. The Teflon sample with the highest PM2.5 concentration, representative of both weekdays and weekends, was selected for morphological analysis using Scanning Electron Microscopy-Energy Dispersive X-ray (SEM-EDX) and elemental characterization using Energy-Dispersive X-ray Fluorescence (ED-XRF) Epsilon. SEM images revealed distinct morphological characteristics at each site. In Bandung, particles were irregularly shaped, agglomerated, and flaky, with sizes ranging from 1.1-1.6 µm on weekdays and 0.9-1.3 µm on weekends. Jakarta has particles with semi-crystalline, tabular, elongated, and puff-like morphology, with sizes predominantly from 0.5-0.8 µm on weekdays and 0.9-1.3 µm weekends. In Tangerang, particles were irregularly faceted and agglomerated, with sizes between 0.5-1.3 µm on weekdays and 0.9-1.4 µm on weekends. Teflon-derived minerals (C,F) were present across all sites. EDX spectra revealed Ca-rich particles in Bandung, while S-rich particles were observed in Jakarta and Tangerang. XRF analysis further proved the major and minor elements, reflecting local pollution sources. The combined use of SEM-EDX and XRF offers a comprehensive profile of PM2.5, highlighting specific pollution sources in each city.