Car Air Purifiers: How Effective Are They, and Should You Buy One?

It’s that time of year again - everyone is coughing and sniffling, skies are grey, and air quality warnings are lighting up in red across large swathes of India. Urban areas are especially badly affected through much of the festive season and into the winter. Debates might rage about the causes – stubble burning, car pollution, construction, and changes in wind direction are commonly blamed – but we can all agree that such conditions make us miserable and compromise our long-term well-being.

Not everyone can stay cooped up indoors with the windows closed and an air purifier running all day. In fact, if you have to spend a lot of time on the road, you’re probably breathing in some of the worst fumes and suspended particulate matter. While a few cars in India do have integrated air filtration or purification systems, there’s a growing market for portable units that can simply be placed in any vehicle.

Various types of car air purifiers are available in India, ranging from under ₹1,500 to well over ₹15,000. Several major brands including Philips, Sharp, Honeywell, Qubo and Ambrane offer multiple options, but you’ll also come across lots of smaller names if you’re shopping online.

Here are the various factors you should consider when shopping for a car air purifier.

Size and types of car air purifiers

There are two primary car air purifier types - smaller ones that fit into a cupholder, and larger ones that must be placed elsewhere. The larger ones are usually seen strapped to a seatback or armrest in order to keep them from sliding around and becoming a safety hazard. Some can be placed on the top of the dashboard using an anti-slip map or any form of adhesive. Larger ones tend to be more expensive and work more like home air purifiers.

While both types are suitable for most types of passenger cars, there are a few factors that play into deciding which one you should buy. First, check the power source - smaller cupholder units are usually powered by a car’s USB port, while larger ones need to be plugged into a 12V outlet. 

It’s also important to check what kind of filter each air purifier uses – reusable or disposable. The average lifespan, and easy availability of replacement filters should be considered. Smaller air purifiers might come with washable filters, but in that case you should check exactly what level of purification is promised, and what types of contaminants each model claims to capture.

Filtration quality and specifications of car air purifiers

Because a car cabin is a relatively small enclosed space, even small air purifiers should be highly effective. Ideally, you should be able to count on clean air within a few minutes of turning your air purifier on. Check for the total CADR (Clean Air Delivery Rate) which is measured in cubic metres per hour. This tells you how long the purifier will take to process the amount of air within the volume of your car cabin. You could see multiple specifications, aimed at filtering dust, car exhaust, fine particles, and commonly found domestic pollutants called VOCs (Volatile Organic Compounds). Airborne particulate matter can be categorised based on size, and you might come across separate ratings for PM2.5 and PM10 filtration, which refer to the diameters of each particle, measured in microns. 

Those who suffer from allergies to airborne triggers such as pollen and spores should also check specifically for filtration quality claims regarding these.

HEPA (High Efficiency Particulate Air) is the most commonly used filter type, and this implies adherence to certain standards such as 99.95 percent filtration of 0.3-micron particles, which include pollen and dust as well as certain microorganisms such as viruses and bacteria. These filters are typically need to be replaced once they are saturated. For car air purifiers, the useful life is measured in hundreds of hours, though some manufacturers might describe their life in terms of months, assuming a few hours’ use per day. 

A pre-filter can extend the life of an HEPA filter by catching large particles before they reach it, so check whether your chosen air purifier is equipped with one. These are generally made using activated carbon, and also help with absorbing odours and gases. 

Some air purifiers also claim to use UV light to sterilise your car’s cabin, claiming to be effective against viruses and bacteria.   

Features of car air purifiers

While filtration is of course the most important criteria, several car air purifiers offer extra features that might swing your decision. Some models can diffuse essential oils or scents of your choosing, acting as air fresheners. Some claim to eliminate odours, such as the smell of cigarettes.

Check for features like multiple fan speed settings, so you can choose between high-power air circulation and silent operation, or even an automatic setting so the unit can respond to real-time air quality changes as needed. The unit should be easy to control, with a screen that shows essential information including an air quality rating and alerts for things like filters needing to be replaced. Some models even have additional convenience features such as pass-through USB ports for charging other devices. 

Who should buy a car air purifier?

Anyone concerned about the quality of air they breathe should consider buying air purifiers for their home and anywhere else they spend a lot of time. If your commute takes over an hour each day and you’re often stuck in traffic, you might be breathing in quite a lot of pollution and other harmful particles. Moreover if you or anyone else you know smokes in your car, air quality can drop quite seriously. 

A car air purifier could help reduce the chances of catching or exacerbating respiratory conditions, and could also provide relief from allergens and irritants. Of course, to help it be more effective, you should keep the inside of your vehicle clean and use a vacuum cleaner to suck up dirt and debris that might be lying on the floor, hiding in crevices, or clinging to your upholstery.