A Novel Methodology for Determining the Efficacy of Interventions Targeting Urban Air Pollution Hotspots

Abstract Description: Globally, there is an increasing uptake on policy interventions aimed at reducing the burden of air pollution on human health. The use of traffic management interventions such as low or zero emissions zones to reduce exposure to traffic related air pollution are increasing in popularity around the world. However, quantifying the effects of such interventions is challenging, with results from previous studies lacking or presenting conflicting information. Here we present a novel methodology, using data collected from a micro-network of low-cost FilterMote PM10 samplers, located in the isolated Southern Hemispheric City of Auckland. The data were then analyzed with a combination of techniques (gravimetric mass, light-reflectance, x-ray fluorescence and Raman spectroscopy) to identify the composition of ambient particulate. PM10 concentrations from gravimetric estimates along with elemental and light-reflectance results were yielded similar results across the three sites. Mass reconstruction methods identified soil (Al, Si, Fe) and sea salt (Na, Cl) as being the most common constituents; trace levels of heavy metals (Cr, Fe, Co, Ni, As, Mo, Cd, Sn, Sb, Ba) were also identified. Raman spectroscopy successfully identified variations in the composition in soot, enabling links to diesel vehicles servicing the port. The airshed was well mixed across the locations with some notable impacts linked to urban design. A common tracer of shipping emissions (Ni, V) were not correlated; a significant finding due to the long history of correlated Ni/V across speciation samples. The novel combination of techniques was useful in highlighting information about the composition of ambient PM10 from Auckland. Further PM characterization studies are needed for source attribution, to develop more effective policy interventions and mitigation measures.