Intra-city particulate elemental characteristics and variabilities in Jakarta

Abstract

Jakarta has experienced a particulate pollution problem in the last few decades. Our study aimed to investigate particulate spatial variability and identify the associated sources in more detail by measuring their composition in Jakarta at three sites in a north–south transect. We collected the mass using the Dichotomous Gent SFU and analysed the elemental concentration with a Smoke Stain Reflectometer and ED-XRF. Principal Component Analysis (PCA), correlation, and Conditional Bivariate Probability Function (CBPF) techniques were used to reveal the element's source attribution probabilities and their directional strengths. Black carbon (BC) and sulphur (S) were the major contributors to PM2.5 but not always to coarse particles. Motor vehicle fuel was a significant source of sulphur in most areas. Multiple-site data analyses reveal that in the city centre, traffic congestion was the main source of BC, while in South Jakarta, BC primarily originated from open waste/biomass burning. However, in North Jakarta, CBPF also suggested industrial coal and vessel diesel oil from the direction of the port as probable sulphur sources. While local sources dominated, the fine and coarse particle CBPFs demonstrated that some elements arrived from out-of-border sources during higher wind speed events. Long-distance anthropogenic and natural sources might include industries in the neighbouring cities and fumarolic emissions from the volcanic terrains in southern Jakarta. These results showed diverse sources and composition of PM in Jakarta's north-to-south transect. The large proportion of calm wind underscores the contrasted local sources' contribution to each site, leading to the apparent spatial and source variability within sites.