| Title | Kia Manawaroa- NgÄ Ä€kina Te Ao TÅ«roa Kounga Rangi - the Influence of Geothermal Emissions on Airborne Particulate Matter Composition |
|---|---|
| Authors | James WARBRICK, Perry DAVY, Agnes MAZOT, Bill TROMPETTER, Andreas MARKWITZ, Diane BRADSHAW |
| Year | 2020 |
| Conference | World Geothermal Congress |
| Keywords | MÄori, geothermal emissions, cultural activities, tourism, air pollution sources, Whakarewarewa, Rotorua |
| Abstract | Airborne particulate matter is of worldwide interest due to the potential for human health effects and climate forcing impacts. This paper presents the results from four years of air particulate matter sampling at Whakarewarewa, an active geothermal area in Rotorua, New Zealand. Whakarewarewa is an iconic centre of MÄori culture that recognises the importance of te ao MÄori (MÄori world view) – a holistic understanding of our environment that benefits all New Zealanders. Research developed in recent years has sought to articulate MÄori cultural values to better understand the immediate and chronic health effects caused by air pollution events. The work also formed part of the New Zealand-led International Atomic Energy Agency programme RAS2079, Assessing the Impact of Urban Air Particulate Matter on Air Quality. This paper combines indigenous knowledge and western science in the fields of volcanology and environmental science, in particular air pollution. Samples of air particulate matter were collected at the Whakarewarewa village and compositional analysis was used to identify sources of air particulate matter pollution (APM) at the geothermal location with an aim to provide information on air pollution in a place where geochemistry may play a vital role in altering the composition of air particulate matter. We apportion the sources and link them with local emission sources and meteorological observations to elucidate mechanisms for air pollution transport. For this work, two size fractions of particulate matter (PM2.5 and PM10-2.5) were sampled simultaneously and collected on polycarbonate filter media. Nuclear analytical techniques (Ion Beam Analysis and X-ray fluorescence) were used to analyse the elemental composition (Na to U) of the samples while light reflectance was used to determine black carbon concentrations. Information on the sources contributing to the airborne aerosol was extracted from the data using multivariate factor analysis (positive matrix factorisation). The elemental composition results show that sulphur species were a major component of the fine fraction of particulate matter (PM2.5) while chlorine and silicon were primary components of the coarse fraction (PM10-2.5). Source apportionment analysis revealed that geothermal emissions provide a significant contribution to airborne particulate matter at the site, as both secondary sulphate (from gas-to-particle atmospheric reaction processes) along with sulphur and metal-rich crustal matter aerosol species were identified. Other sources of aerosol include anthropogenic biomass combustion (during winter) used for domestic space heating, motor vehicle emissions and natural sea salt. By coupling the results with meteorological data, the origins of the contributing sources were inferred. |