Assessment of the capacity of vehicle cabin air inlet filters to reduce diesel exhaust-induced symptoms in human volunteers

Abstract

BackgroundExposure to particulate matter (PM) air pollution especially derived from traffic is associated with increases in cardiorespiratory morbidity and mortality. In this study, we evaluated the ability of novel vehicle cabin air inlet filters to reduce diesel exhaust (DE)-induced symptoms and markers of inflammation in human subjects.MethodsThirty healthy subjects participated in a randomized double-blind controlled crossover study where they were exposed to filtered air, unfiltered DE and DE filtered through two selected particle filters, one with and one without active charcoal. Exposures lasted for one hour. Symptoms were assessed before and during exposures and lung function was measured before and after each exposure, with inflammation assessed in peripheral blood five hours after exposures. In parallel, PM were collected from unfiltered and filtered DE and assessed for their capacity to drive damaging oxidation reactions in a cell-free model, or promote inflammation in A549 cells.ResultsThe standard particle filter employed in this study reduced PM10 mass concentrations within the exposure chamber by 46%, further reduced to 74% by the inclusion of an active charcoal component. In addition use of the active charcoal filter was associated by a 75% and 50% reduction in NO2 and hydrocarbon concentrations, respectively. As expected, subjects reported more subjective symptoms after exposure to unfiltered DE compared to filtered air, which was significantly reduced by the filter with an active charcoal component. There were no significant changes in lung function after exposures. Similarly diesel exhaust did not elicit significant increases in any of the inflammatory markers examined in the peripheral blood samples 5 hour post-exposure. Whilst the filters reduced chamber particle concentrations, the oxidative activity of the particles themselves, did not change following filtration with either filter. In contrast, diesel exhaust PM passed through the active charcoal combination filter appeared less inflammatory to A549 cells.ConclusionsA cabin air inlet particle filter including an active charcoal component was highly effective in reducing both DE particulate and gaseous components, with reduced exhaust-induced symptoms in healthy volunteers. These data demonstrate the effectiveness of cabin filters to protect subjects travelling in vehicles from diesel exhaust emissions.

Characterization of Airborne Particles Collected from Car Engine Air Filters Using SEM and EDX Techniques

“…These particles showed a diameter of between 16 and 0.7 µm, indicating that these filters are capable of retaining particles smaller than 2.5 µm. These results are comparable to published studies about vehicle cabin air inlet filters [29], somehow coinciding with the HEPA standards [15,26]. The design of automotive filters is based on their ability to filter particles, which is dependent on the mesh and the structure and composition of the fiber [30].…”

Decreased blood pressure associated with in-vehicle exposure to carbon monoxide in Korean volunteers

“…Individuals sensitive to such changes, including pregnant women and children, as well as healthy adults, also use the car. Hence, the pollutants flowing in from outside, such as CO, should be managed [ 39 , 40 ].…”

Understanding Air Pollution and Cardiovascular Diseases: Is It Preventable?

“…Another study documented that the use of exhaust particulate traps on diesel-powered vehicles is a highly efficient method of reducing particle exposure and providing beneficial effects on biomarkers of cardiovascular health [43••]. However, Muala et al reported that while exhaust-induced symptoms reported by subjects decreased, the use of cabin air inlet filters including activated charcoal did not show any significant changes in any inflammatory markers in the peripheral blood samples 5 h post exposure [44]. Overall, results suggest that cabin filters and/or diesel particle traps can reduce exposure to traffic-related air pollutants and can be effective in reducing associated adverse cardiovascular health changes.…”