What is a PM2.5 Air Filtration System in a Car?

HEPA filters. Advanced Air Cleaner. Bioweapon Defense Mode. Before COVID-19, these sorts of features in an automobile were perhaps nice to have for some people but unlikely to be on the top of anyone's request list for a new car. Now, though, we're all thinking about how airborne viruses spread from person to person, so we're learning new vocabulary.

Take, for example, the reference "PM2.5." This is shorthand for fine particulate matter (PM) in the air, specifically the tiny inhalable particles measuring 2.5 micrometers (also known as microns) in diameter. So, if a filter is rated to PM2.5, that means it traps any airborne item larger than 2.5 micrometers, which is incredibly tiny.

The U.S. Environmental Protection Agency says most fine particulate matter forms in the atmosphere because of chemical reactions between pollutants. The World Health Organization says exposure to pollution made up of tiny particulate matter causes an estimated 4.2 million premature deaths worldwide per year. If you live in the U.S., you can see the current air quality rating on the EPA's AirNow page.

Getting back to Advanced Air Cleaner and Bioweapon Defense Mode, the latter is what Tesla calls its in-car filtration system, and the former is the name for Volvo's new world-first premium air quality technology. Volvo's Advanced Air Cleaner (AAC) doesn't just ionize and filter "up to 95 percent of all PM2.5 particles," it also monitors PM2.5 levels in the cabin on equipped vehicles. This AAC system is available on the Volvo V90, Volvo V90 Cross Country, Volvo XC90, and all 60 Series Volvo models.

If you're wondering how PM2.5 filtration affects COVID-19 particles, which are smaller than 2.5 (they're around 0.1 microns in diameter), you're not alone. Automakers aren't saying that their PM2.5 filters will protect you from COVID, but they could still positively impact a person's health in relation to COVID. Harvard researchers found a link between higher air pollution levels and COVID mortality rates, but the data is limited since COVID-19 is a new disease.

It's worth noting that COVID particles don't float on their own and always bond to something larger. A PM2.5 filtration system can capture larger hosts measuring 2.5 microns or more, and with a significant degree of success.

While it's good that increasing numbers of vehicles can clean the air inside their cabins, the truth is that our transportation network is responsible for a lot of the ambient PM2.5 pollution in the air in the first place. Automobile exhaust, brake dust, tire abrasion, and road wear contribute to PM2.5 levels in the air. Cleaner vehicles create less pollution, so even if your car doesn't have a fancy new filter, the next time you see an EV on the road, thank the driver.