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A breath of fresh air in vehicle technology

The quality of the air we breathe has come into sharp focus with the Coronavirus pandemic. Here we discover how car manufacturers are now installing advanced filtration systems to ensure the comfort and safety of occupants in the face of a wide range of pollutants.

While countryside air may be purer, people can be affected by allergies to trees, plants and pollen
While countryside air may be purer, people can be affected by allergies to trees, plants and pollen - Image: Volvo.

According to the World Health Organization, air pollution causes as many health risks as smoking and unhealthy diets. It estimates 99% of the world’s population live in places where air pollution levels exceed its guidelines with seven million people dying every year as a direct result.

Heart disease, asthma, strokes, cancer and more have all been linked to air pollution while the number of people with allergies to pollen, dust and mould for example is increasing every year.

But it is only relatively recently that the automotive industry has woken up to the fact that as we spend a considerable proportion of our time in vehicles, then it has a responsibility for limiting our exposure to pollution with air flowing into a vehicle at a volume of up to 540,000 litres per hour.

Martin Klein, vice president Engineering Filter Elements at filtration specialist Mann+Hummel, said: “People spend the majority of their time indoors. It doesn’t matter whether it’s at home, at school, at work or in vehicles.

“Fine dust, bacteria, harmful gases, pollen and allergens are present in buildings as well as in vehicles. The only difference is what type they are, whether they come from the outside or are present in or originate from the interior.”

Advanced filtration

Advanced filtration systems are now becoming standard features on many vehicles with manufacturers increasingly using them as a selling point.

For example, Tesla uses a high efficiency particulate air (HEPA) filtration system to effectively remove pollen, bacteria and pollution from the outside air before they enter the cabin. It then scrubs the air inside the cabin to eliminate any trace of particles.

The system is activated using a feature known as Bioweapon Defense Mode with Tesla claiming it is hundreds of times more efficient than standard automotive filters.

It was tested in a variety of realworld situations from rush hour freeways to pasture and marsh land as well as in a laboratory with a car put into a bubble contaminated with extreme levels of pollution registering 1,000 μg/m3 of PM2.5 (fine particulate matter) against the US Environmental Protection Agency’s ‘good’ level of 12 μg/m3.

In under two minutes, the HEPA filtration system scrubbed the air to a point where pollution levels were undetectable. Even the outside air was cleaned with PM2.5 levels reduced by 40%.

Air purification

Jaguar Land Rover has also developed a prototype cabin air purification system which it says reduces viruses and airborne bacteria by 97% following laboratory tests.

It uses Panasonic’s nanoe X technology which employs a high voltage to create trillions of Hydroxyl (OH) radicals enveloped in nano-sized water molecules. These denature the virus and bacteria proteins, helping inhibit their growth. They also deodorize and inhibit allergens within the cabin.

Significantly, it has been tested on the coronavirus by global research organization Texcell with results showing more than 99.995% of the virus was inhibited across a two-hour period.

Dr Steve Iley, chief medical officer at Jaguar Land Rover, said: “This technology is a great example of being able to harness the power of nature. Hydroxyl Radicals are one of the most important natural oxidants in chemistry and have been helping to clean our atmosphere for millennia, removing pollutants and other harmful substances. The creation of this technology and our advanced research is the first step in deploying this scientific phenomenon within vehicle cabins of the future.”

Meanwhile, Volvo’s Advanced Air Cleaner system has been certified by the Allergy Standards program to remove up to 99.9% of grass, tree and weed pollen allergens from incoming air. It combines a synthetic fibre-based filter and ionisation.

Electrostatic forces

Particles entering the filtration system are charged by ions emitted to the air flow. They are then trapped in the filter. The filtration force is mostly mechanical for particles > 1 μm whilst particles < 1 μm are removed with both mechanical and electrostatic forces.

As a result, 95% of all PM 2.5 particles are removed from the cabin along with more than 97% of airborne viruses and up to 95% of existing viruses in the vehicle.

Dr Maria Bernander, occupant health effects expert at Volvo, said: “By helping our customers improve the air quality inside their Volvo car, we will help reduce the adverse health effects associated with air pollution, allergens and fine particulates.

“In addition to personal health benefits, studies have shown cleaner air can also help boost concentration which can help you stay more focused during the drive.”

Volvo cars also produce live data showing outdoor pollen and air quality levels via an in-car app in the centre display allowing drivers to adjust if necessary. These include PM 2.5, PM 10, NO2, O3, SO2 and CO. Pollen levels are also indicated including grass, weed and various types of trees while a sensor also measures PM 2.5 levels inside the cabin.

The Advanced Air Cleaner has been tested against timothy grass, birch tree and ragweed pollens by ASL and against Phi6 and MS2 viruses by independent Austrian research and testing institute OFI.

Safer experience

Air quality inside a vehicle has also played a role in some manufacturers’ attempts to make journeys more relaxing, removing stress and anxiety and so creating a more enjoyable and safer experience.

In 2021, Ford developed a Mindfulness Concept Car incorporating a range of technologies and features including hygienic cabin air which is cleaned before the driver enters the car.

The system, Unlock Purge, is activated by the key fob or an app and provides a burst of clean and fresh cabin air via the climate control before the driver enters the vehicle. A premium filter helps remove almost all dust, odors, smog, allergens and bacteria-sized particles.

In addition, UV-C light diodes stop the reproduction of viruses and germs on smartphones, screens and surfaces, for a more hygienic cabin environment.

Clearly, this technology is advancing rapidly and it may not be long before we step inside our cars rather than outside a building for a breath of fresh air.

Pure air for passengers
Cabin air quality is an increasingly important factor in the design of the new generations of vehicles. By
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