Experimental and modelling assessment of a novel automotive cabin PM_2.5 removal system

Poor air quality inside vehicles and its impact on human health is an issue requiring attention, with drivers and passengers facing levels of air pollution potentially greater than street-side outdoor air. This paper assesses the potential effectiveness of a car cabin filtration system to remove fine particulate matter PM_2.5 and improve air quality for car passengers. The study was conducted as a practical evaluation coupled to a model implementation. First, the effectiveness of PM_2.5 filter material was investigated in a chamber experiment under a range of environmental and loading conditions using a realistic automotive auxiliary scrubber. Second, implementation of such a system was evaluated in a full air flow 3D computational fluid dynamical (CFD) model configured for a realistic cabin and ventilation system, and related to the chamber results through a simple decay model. Additionally, performance of low-cost dust sensors were evalu- ated as potential cabin monitoring devices. The experiment and modelling support the feasibility of a robust system which could be integrated into automotive designs in a straightforward manner. Results suggest that an auxiliary scrubber in the rear of the cabin alone would provide sub-optimal performance, but that by incorporating a PM_2.5 filter into the main air handling system, cabin PM_2.5 concentrations could be reduced from 100 <i>µ</i>g m<i>⁻</i>³ to less than 25 <i>µ</i>g m<i>⁻</i>³ in 100 seconds and to 5 <i>µ</i>g m<i>⁻</i>³ in 250 seconds. A health impact assessment for hypothetical occupational driver populations using such technology long term showed considerable reductions in indicative PM_2.5 attributable mortality.