Mr.Anuwat Rumrod/Shutterstock A modern car will most likely have two types of air filters. They essentially do the same thing, but for different purposes. Under the hood is the engine air filter that prevents dirt and grit from damaging parts like turbochargers, valves, pistons, and cylinder liners. And then there's the cabin air filter, which cleans the air you breathe while inside the car. You can find a few different types of these filters, but choosing the right one matters for those suffering from allergies or cardiovascular problems. You can see why this is so important when looking at a 2023 Canadian study about in-vehicle cabin air filtration published at the National Library of Medicine. It said that traffic-related air pollution (TRAP) is linked to inflammation, autonomic dysfunction, and oxidative stress. The highest levels of TRAP exposure were reported to occur during daily commutes — particularly while sitting inside a car in rush hour traffic. Driving in Los Angeles, for instance, contributes anywhere from 33% to 45% of a person's ultrafine particle exposure for the entire day, making those aforementioned health issues worse. What's concerning is that driving only makes up 6% of an average person's day in Los Angeles (not counting Uber drivers, of course). The good news is that a cabin air filter can reduce that particulate exposure by about 30%. There are three main types of cabin air filters for cars, and of those types, the study found that high-quality electrostatic filters were most effective at cleaning the air. Other types are still effective in helping you breathe, but they don't provide quite as much overall protection. Even so, price is another matter to consider, especially since — unless you specifically get an air filter that can be cleaned — these filters will eventually need to be replaced. The types of cabin filters and what they can do Angela Feltes/Shutterstock The most common and most affordable cabin air filter is a particle filter. Typically made from pleated paper or synthetic polyester medium, it can remove as much as 99% of air particles too small to see. The next step up is a carbon air filter, which utilizes activated charcoal infused in the filtering media to trap smells, as well as harmful chemicals like nitrogen oxides and sulfur dioxide. Finally, electrostatic cabin filters – also referred to as High-Efficiency Particulate Air (HEPA) filters — feature electrostatically-charged filters. They're able to trap even smaller particles, covering things like cigarette smoke and brake dust. HEPA cabin filters are practically necessary for car owners with respiratory issues or those who desire the cleanest, purest air possible. The only downside to those higher-quality variants is that they typically cost more than a basic particulate filter. This isn't always a major concern, with some HEPA filters priced from $10 to $25. But certain vehicle models require specific filters that will ramp up the cost, possibly reaching $80 or more. If you're trying to find the right filter type for you, it's probably worth knowing how often to change the cabin filter in the first place. If you're facing dusty areas that force you to use a higher-quality filter, you'll probably need to swap it out sooner rather than later, giving you another reason to take cost into consideration. In some cars, replacing the cabin air filter is typically a quick DIY fix, but some can leave you pulling hairs, so consulting the owner's manual is highly necessary.