Measuring – and mitigating – vehicle passenger exposure to air pollution
Air pollution is deadly. According to the World Health Organization(opens in new window), it is responsible for at least 4.2 million premature deaths every year – and maybe as many as 8.8 million. Even more concerning is that it is nearly impossible to escape being exposed to air pollution. Not only can it make its way into your home and office, it can also infiltrate your car. “As this polluted air from the outdoors undergoes an exchange with the air inside the vehicle cabin, occupants may suffer elevated exposure to air pollutants such as nitrogen dioxide, emitted from the exhausts of other vehicles,” says William Bloss, professor of Atmospheric Science at the University of Birmingham(opens in new window) in the United Kingdom. With the support of the EU-funded MMAP-VEX project, Bloss, together with Vasileios Matthaios, a Marie Skłodowska-Curie(opens in new window) researcher and now lecturer in Environmental Public Health at the University of Liverpool(opens in new window), set out to understand the extent of in-vehicle air pollution and how this risk can be mitigated. “The aim of the project was to investigate air quality inside vehicle cabins and examine practical and affordable mitigation measures that help reduce occupants’ exposure to air pollution and so improve their health,” adds Matthaios.
The benefits of carbon-activated filters
With a focus on nitrogen dioxide (NO2) gas, which in urban areas comes primarily from diesel traffic, and fine particles, the project researched exposure levels in a series of cars under real-world driving conditions. It also tested various mitigation measures, such as the use of different types of air cabin filters and indoor air purifiers. What they found was that, although most cars come with air filters, these filters are primarily designed to remove pollen, not NO2 and other toxic gases. However, when a carbon-activated filter is used, NO2 gases are also removed. In fact, a newly activated carbon air filter can reduce in-vehicle NO2 concentrations by as much as 93 %. However, like all filters, these filters have an expiry date. Because the performance of carbon air filters drops by about 7.6 % per month of use, researchers recommend replacing them every six to 12 months. “By choosing the appropriate ventilation settings and cabin air filters, drivers and passengers have the potential to significantly cut their exposure to NO2,” explains Bloss. “Even better, these carbon air filters are readily available and remarkably inexpensive.”
Raising awareness about in-vehicle air quality
Not only did the MMAP-VEX project succeed at providing simple and practical solutions for reducing the risk posed by air pollution to drivers and passengers, perhaps more importantly, it raised awareness about in-vehicle air quality. In addition to garnering substantial media coverage, researchers published several articles(opens in new window) in a high-impact factor, peer-reviewed journal(opens in new window) – with two additional papers in the works. The project also produced a video(opens in new window) to help the general public understand in-vehicle air quality and what they can do to reduce their risk. “As the first research initiative to provide evidence-based recommendations for cabin filtration media, our work put the spotlight on this important – yet often overlooked – aspect of air pollution,” concludes Matthaios. While the project provided a lot of novel insights for in-vehicle air quality and filtration, there’s still plenty of work to do. For instance, Bloss and Matthaios are currently looking at studying the toxicity of the fine particles and other organic compounds that can be found in vehicle cabins.
