According to research presented in a report by WM Air, the West Midlands Air Quality Improvement Programme at the University of Birmingham, charcoal filters, which cost between £10 and £20, can effectively remove NO2 from vehicle cabin air.
Cheap charcoal air filters offer improvements to in-vehicle air quality
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NO2 is a common air pollutant that can aggravate asthma and raise the risk of respiratory infections.
Because traffic emissions are a major source of NO2, road users inside vehicles are exposed as air circulates from outside through open windows and ventilation systems, as per ScienceDaily.
While ventilation systems currently filter air, it is usually through a pollen filter.
These keep tiny particles and pollen out of the vehicle, but they have little effect on gases like NO2.
In contrast, activated carbon filters remove NO2 through a process known as adsorption, in which NO2 reacts with the carbon and sticks to the surface area of the filter.
The carbon filter, like the pollen filter, loses effectiveness over time, so it should be replaced on a regular basis when the vehicle is serviced.
"Our findings clearly show that there are benefits to switching to activated carbon air filters, reducing exposure to NO2 and the risk of related adverse health effects," said lead researcher Dr. Vasileios Matthaios.
These filters are simple, effective, and inexpensive, and they should be considered, especially for people who spend a lot of time in cars, such as professional drivers.
The findings are summarized in a research paper published in Science of the Total Environment.
The researchers tested NO2 in ten different vehicles ranging in size and type for this study (petrol, diesel, hybrid and electric were all included).
Air quality measurements were taken inside the vehicles under various ventilation conditions (AC turned on or off and windows either closed or partially open).
Each vehicle was tested three times: once with its original air filter, once with a pollen filter, and finally with the activated charcoal filter
The researchers discovered that when the windows were closed and the ventilation system recirculated air, in-vehicle NO2 concentrations were 1.6 times lower than when the windows were open.
When new standard pollen filters were installed, NO2 concentrations remained nearly constant between closed windows and fresh air coming through the ventilation system, as well as when the windows were open.
In-vehicle NO2 levels were 14.3 times lower with closed windows and recirculated air when activated carbon filters were installed.
Even with the ventilation system providing fresh air, NO2 levels were 6.6 times lower than when the windows were open.
Maintaining proper ventilation is also important for avoiding drowsiness.
Particulate filters are effective at cleaning cabin air, but activated charcoal filters outperform them.
Activated charcoal filters not only trap dust and debris, but they also absorb fumes and odors, as per Premium Guard.
The charcoal found in cabin filters isn't the kind you'd use on a grill. It is treated with heat and chemicals to control odors.
Adsorption holds gases on the surface of the activated charcoal filter. Activated charcoal is extremely effective due to its porous nature.
Some of the gases that activated charcoal cabin filters control can be extremely hazardous.
Charcoal cabin filters, for example, absorb carbon monoxide and nitrogen oxide, both of which are harmful to one's health.
Activated charcoal cabin air filters may also be coated with an anti-bacterial material.
This keeps harmful bacteria out of the cabin.
Activated charcoal cabin air filters require more frequent replacement than traditional filters.
Replacement of charcoal filters is recommended once a year or every 15,000 miles.
Particulate filters, on the other hand, are typically replaced every 30,000 miles.
Both types of filters should be changed more frequently in vehicles driven in dirty, dusty, or polluted areas.
Charcoal-activated cabin filters, like all cabin filters, are simple to replace. Any do-it-yourselfer can complete the task, and in most cases, no tools are required.
The cabin filter is often found directly behind the glove box in many vehicles. To remove the glovebox, simply push the glovebox tabs inward.
Then, remove the filter cover by pushing a few more tabs. The cabin filter can now be accessed and replaced.
