Charcoal filters can boost air quality in cars

Charcoal filters can boost air quality in cars

There’s a fast, affordable way to boost the air quality inside your car: Grab a charcoal filter.

Scientists at the University of Birmingham in England have found that a charcoal-enhanced cabin air filter can reduce nitrogen dioxide levels by up to 90% compared with outside air. Vehicle emissions are a prime source of nitrogen dioxide, which is often drawn in through ventilation systems or open windows.

And here’s why your typical cabin air filter won’t help: Most of them are built to filter pollen and other particulates but have little effect on air pollutants  like nitrogen dioxide.

Bring on the activated charcoal filter, which is also known as an activated carbon filter. It removes nitrogen dioxide through a process called adsorption [ăd-sôrp′shən]. The carbon grabs onto the nitrogen dioxide molecules, making them stick to the filter’s surface so they can’t pass into the car’s interior.

In their study, the researchers tested nitrogen dioxide levels in 10 types of vehicles. The group included gas, diesel, hybrid and electric cars in a range of sizes. Air-quality measurements were taken in a variety of ventilation conditions, including while using vents and air-conditioning or with open windows. Each vehicle underwent a trio of tests using its original cabin air filter, a pollen filter and an activated carbon filter.

On average, standard pollen filters produced almost no significant improvement in nitrogen dioxide levels.

And then there was the carbon filter: Nitrogen dioxide levels were 6.6 times lower than with open windows. With closed windows and recirculated air, nitrogen dioxide levels were more than 14 times lower.

Indeed, the road to breathing easier behind the wheel could be as simple as a cabin filter change.

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