Receptor modeling studies for the characterization of air particulate lead pollution sources in Valenzuela sampling site (Philippines)

Valenzuela, an industrial district in the northwestern part of Metro Manila, Philippines, was found to have higher particulate and lead levels than in the other Metro Manila air sampling stations of the Philippine Nuclear Research Institute. Results in 2004–2009 show that while PM10 annual mean levels are in compliance with the long and short–term Philippine standards for PM10, PM2.5, annual mean levels are in exceedance of the long– term standard of the US EPA (15 µg m–3). Energy–dispersive x–ray fluorescence spectrometry, a non–destructive multi–element nuclear related analytical technique, was used to analyze the elemental components of the air particulates. Positive matrix factorization, a receptor modeling tool, was used to identify and apportion air pollution sources. This study has identified Pb sources in both the coarse (PM2.5-10) and the fine (PM2.5) fractions. The conditional probability function analysis plots of 2008 Pb levels in both the coarse and the fine fractions show patterns for probable sources in the 2008 data similar to that in the 2005 data indicating that Pb sources in 2005 were the same Pb sources in 2008. Further studies to locate possible sources of lead are needed to validate the results of this finding.