When you are sitting inside of your vehicle with the doors closed, it’s easy to assume you are sitting in an impervious bubble. One, where whatever happens to be going on outside, from mild smells to serious pollution cannot reach you.
Unfortunately, that’s not how things work. Instead, the air inside a car can contain higher concentrations of pollutants than the air immediately surrounding it.
A cabin filter is the only thing standing between the air that you and your passengers breathe in and everything the road throws at it. So, this makes it important to know how yours works, including when a replacement is due.
New to cabin filters and how they work? Or, want to ensure that the air in your vehicle is being filtered properly? This post is for you.
What Is Actually in the Air You Breathe While Driving?
Road environments are among the most polluted spaces most people regularly occupy.
Traffic exhaust produces nitrogen dioxide, carbon monoxide, particulate matter and volatile organic compounds (VOCs). In queuing traffic or road tunnels, these concentrations increase significantly because you are effectively sitting in the exhaust output of the vehicles directly ahead.
Beyond exhaust, cabin air can contain pollen, road dust, tyre and brake wear particles, fungal spores and bacteria.
During spring and summer, pollen counts on major roads can be considerably higher than in open countryside, partly because vehicles disturb and circulate settled pollen as they pass.
For most healthy adults, short-term exposure to these pollutants is an inconvenience rather than a serious risk.
For drivers or passengers with asthma, hay fever, rhinitis or other respiratory sensitivities, the cumulative effect of regular commuting in polluted conditions can be far worse.
How A Cabin Filter Helps
Cabin filters sit within your vehicle’s HVAC (heating, ventilation and cooling) system and filters all air drawn into the cabin before it reaches the occupants.
A standard particle filter captures dust, pollen, soot and larger particulates using a pleated filter medium, preventing them from circulating through the ventilation system and into the cabin air.
Activated carbon cabin filters go further. The carbon layer absorbs gases as well as particles, which means exhaust fumes, nitrogen dioxide, odours and VOCs are captured rather than passed through.
For drivers who spend significant time in urban traffic or on motorways, an activated carbon filter provides a noticeably better level of protection than a basic particle filter and is worth the modest additional cost.
Hay Fever And Driving
Hay fever is one of the most common reasons people become aware of their cabin filter. Pollen seasons in the UK typically run from late February through to September, with grass pollen season between May and August representing the peak period for most sufferers.
A well-maintained cabin filter with a pollen-rated medium significantly reduces the amount of airborne pollen entering the cabin. It’s not possible to completely eliminate exposure, as pollen can still enter the vehicle through open windows or be brought in on clothing. However, a cabin filter can help remove continuous background exposure.
Drivers with hay fever who find their symptoms significantly worse during commutes, or who notice sneezing and eye irritation worsening with the air conditioning on, should check the condition of their cabin filter. That’s because a blocked or degraded filter can actually worsen symptoms by harbouring trapped pollen and redistributing it into the cabin air rather than capturing it.
When A Dirty Cabin Filter Becomes A Health Issue
A cabin filter that has not been replaced within its service interval does not simply stop working. It progressively degrades in two ways: it becomes physically blocked, reducing airflow and HVAC efficiency and it accumulates biological contamination
When moisture accumulates in the filter medium (i.e. from humid air, condensation or damp conditions), this creates an environment where bacteria and mould can establish. An older, damp filter can actively introduce spores and odours into the cabin air rather than removing them. This is particularly relevant in vehicles that are used infrequently, stored in damp conditions, or where the air conditioning has not been used regularly.
If you notice a persistent musty or stale smell when the heating or air conditioning is running, a contaminated cabin filter is one of the most likely causes. Replacing the filter promptly is the correct response; air fresheners will mask the symptom without addressing the source.
How Often Should You Replace Your Cabin Filter?
Most manufacturers recommend replacing the cabin filter every 12 months or every 12,000 to 15,000 miles, whichever comes first. Drivers in urban areas, those who commute on heavily congested routes, or anyone who regularly drives in dusty or industrial environments should lean towards the shorter end of that interval.
The cost of a cabin filter replacement is low relative to most vehicle maintenance items and the impact of a blocked or contaminated filter on both air quality and HVAC performance makes regular replacement straightforward to justify.
Replace Your Cabin Filter – Shop Online At Filter Services UK
Filter Services stocks cabin filters for a wide range of cars, vans and commercial vehicles, including filters from leading brands.
You can order your chosen cabin filters on our website and we deliver right across the UK. Or, you can visit one of our branches in person.
If you are unsure which filter is correct for your vehicle, get in touch with the team for advice.
On our website, you can browse our full range of cabin filter makes and models to find the right filter for your vehicle.