Composition and source contributions of air particulate matter pollution in a New Zealand suburban town

Wainuiomata, a suburban town located at the southern end of the North Island of New Zealand, is subject to air particulate matter pollution episodes during the winter. The results of fine (PM2.5) and coarse (PM2.5–10) particulate matter monitoring in Wainuiomata from July 2006–September 2008 are presented. Receptor modeling was used to determine the sources contributing to particulate matter pollution and mass contributions to ambient particle concentrations from emission sources were estimated. PM10 concentrations displayed a seasonal pattern, with peak concentrations occurring during the winter. The results demonstrate that marine aerosol and crustal matter sources were the primary contributors to the coarse particle fraction, while the fine particle fraction was dominated by biomass burning with smaller contributions from marine aerosol and secondary sulfate particles. Arsenic was found to be present in the fine particle fraction and was associated with biomass burning, suggesting the use of copper chrome arsenate treated timber for domestic heating. Analysis of seasonal differences revealed that biomass burning was largely responsible for fine particle pollution episodes during the winter. Marine aerosol featured significantly as a PM10 source all year due to New Zealand’s remote oceanic location.