Source Apportionment of Atmospheric PM 10 in Makkah Saudi Arabia by Modelling Its Ion and Trace Element Contents with Positive Matrix Factorization and Generalised Additive Model.

In this paper, the emission sources of PM 10 are characterised by analysing its trace elements (TE) and ions contents. PM 10 samples were collected for a year (2019-2020) at five sites and analysed. PM 10 speciated data were analysed using graphical visualization, correlation analysis, generalised additive model (GAM), and positive matrix factorization (PMF). Annual average PM 10 concentrations (µg/m 3 ) were 304.68 ± 155.56 at Aziziyah, 219.59 ± 87.29 at Misfalah, 173.90 ± 103.08 at Abdeyah, 168.81 ± 82.50 at Askan, and 157.60 ± 80.10 at Sanaiyah in Makkah, which exceeded WHO (15 µg/m 3 ), USEPA (50 µg/m 3 ), and the Saudi Arabia national (80 µg/m 3 ) annual air quality standards. A GAM model was developed using PM 10 as a response and ions and TEs as predictors. Among the predictors Mg, Ca, Cr, Al, and Pb were highly significant ( p < 0.01), Se, Cl, and NO 2 were significant ( p < 0.05), and PO 4 and SO 4 were significant ( p < 0.1). The model showed R-squared (adj) 0.85 and deviance explained 88.1%. PMF identified four main emission sources of PM 10 in Makkah: (1) Road traffic emissions (explained 51% variance); (2) Industrial emissions and mineral dust (explained 27.5% variance); (3) Restaurant and dwelling emissions (explained 13.6% variance); and (4) Fossil fuel combustion (explained 7.9% variance).