Many studies have addressed Ambient Air Pollution (AAP) that arises from traffic, and its associated negative impacts on public health. However, less has been done to understand Indoor Air Quality (IAQ) despite the average person now spending more than 90% of their time indoors (Klepeis et al. 2001). Around one hour of this indoor exposure is spent inside vehicles (Müller et al. 2011), and is referred to as Vehicle Interior Air Quality (VIAQ). This exposure is important to understand given the immediate proximity to significant pollutant sources (other vehicles), plus, in urban areas, high AAP concentrations compared to other micro-environments.

To address this knowledge gap, two NAQTS V1000 Integrated Air Quality Monitors were used to simultaneously monitor inside-outside four vehicles for Particle Number (PN) and Carbon Dioxide (CO2). The vehicles were analysed to understand Ingress Ratio (how much ambient PN is getting into the vehicle cabin) and Stuffiness (how well the vehicle is ventilating CO2).