Elemental Composition of Ambient Fine Particles in Urban Schools: Sources of Children’s Exposure

Leigh R Crilley,Eduard Stelcer,Lidia Morawska,Mandana Mazaheri,Godwin A Ayoko,David D Cohen

doi:10.4209/aaqr.2014.04.0077

Abstract

Currently, there is a limited understanding of the sources of ambient fine particles that contribute to the exposure of children at urban schools. Since the size and chemical composition of airborne particle are key parameters for determining the source as well as toxicity, PM1 particles (mass concentration of particles with an aerodynamic diameter less than 1 µm) were collected at 24 urban schools in Brisbane, Australia and their elemental compositions determined. Based on the elemental compositions four main sources were identified; secondary sulphates, biomass burning, vehicle and industrial emissions. While secondary sulphates were likely to be a large contributing source by mass, industrial emissions accounted for the most variation in trace metals in the PM1 that children were exposed to at the schools. PM1 concentrations at the schools were compared to the elemental composition of the PM2.5 particles (mass concentration of particles with an aerodynamic diameter less than 2.5 µm) from a previous study conducted at a suburban and roadside site in Brisbane. This comparison suggested that the more toxic heavy metals (V, Cr, Ni, Cu, Zn and Pb), mostly from vehicle and industrial emissions, were predominantly in the PM1 fraction. Thus, the results from this study points to PM1 as a potentially good particle size fraction for investigating the health effects of airborne particles. Further work is required to confirm this hypothesis.

Highlights

Long-term exposure to airborne particles in adults has been associated with a number of harmful effects to cardiovascular (Brook et al, 2010) and respiratory systems (Pope et al, 2002)
As the results from this study found that PM1 contains notably fewer contributions from crustal material and with these metals (V, Ni, Zn and Pb) found to be preferentially in the PM1 fraction, it suggests based on the size and chemical composition, the PM1 fraction may have greater detrimental health effects compared to PM2.5
The trace elemental composition of the PM1 was analysed at 24 urban schools to determine the sources of airborne particles that children are exposed to at urban schools

Summary

Introduction

Long-term exposure to airborne particles in adults has been associated with a number of harmful effects to cardiovascular (Brook et al, 2010) and respiratory systems (Pope et al, 2002). Due to their immature immune systems and faster breathing rates, children are more susceptible to these detrimental health effects (Zhang and Zhu, 2010; Rückerl et al, 2011). The size and chemical composition of ambient particles are important parameters in determining their toxicity (Heal et al, 2012). In urban environments it has been observed that the majority of the toxic metals, such as V, Ni, Cu, As, Cd and Pb are in the PM1 fraction (Cheng et al, 2009; Moreno et al, 2011)

Methods

Results

Conclusion