Impact of road dust on local air pollution: a case study of Auckland, New Zealand

Urban air pollution is significantly influenced by road traffic, with recent research highlighting the growing significance of non-exhaust emissions (NEEs) such as road dust, brake wear, and tyre abrasion. While electric vehicles offer a pathway to reducing tailpipe emissions, their environmental benefits may be offset by increased NEEs, especially from heavier vehicle fleets. This study investigates the contribution of road dust to PM₁₀ concentrations in Auckland, New Zealand, using a 13-year panel dataset (2006-2019) from three strategically located air quality monitoring sites. PM₁₀ data were sourced from GNS Science and derived through receptor modelling, while traffic flow data were obtained from the New Zealand Transport Agency. Employing panel regression models with fixed effects, we quantify the influence of road dust, meteorological variables such as temperature and wind speed, and heavy vehicle traffic on PM₁₀ levels. Our findings demonstrate that road dust is a dominant and statistically significant contributor to PM₁₀, exceeding traditional tailpipe sources even in a relatively wet climate. The study offers robust empirical insights into the complex dynamics between NEEs, vehicle fleets, and meteorology, providing valuable guidance for policymakers seeking cost-effective and targeted strategies to improve urban air quality in the transition to sustainable transport systems.