Righter than air: with the cost question ever before their eyes, North American OEMs have held back on offering cabin air filtration systems as standard equipment. Still, suppliers and overseas OEMs argue that with the proven health benefits to the driver and passengers, it's the right thing to do

Automotive Industries, March, 2005 by Carla Kalogeridis

Here's a short quiz: What percent of drivers would prefer clean air reside their vehicles, air that is free of pollutants, contaminants and odors? What percentage of passengers?

Obviously a trick question, you say. Everyone who spends time in a vehicle would prefer the cleanest cabin air possible--right? And yet, interestingly enough, although the technology exists to offer pollution- and odor-free vehicle interiors, only about 40 percent of Noah American vehicles contain cabin air filtration systems. Even more interesting are the results of a recent survey that reveals consumers are willing to pay extra for it.

The survey, conducted by The Dohring Co., one of North America's largest providers of market research to the retail automotive community, found that 95 percent of respondents are concerned about air pollutants within their vehicle. (The Dohring Co. conducted this consumer study online among a randomly selected sample of 1,000 Americans from its national member base. The margin of error for the sample is three percent.) Other results of the study include:

* 91 percent of respondents would like to see cabin air filters offered as a standard feature by vehicle manufacturers;

* 83 percent of respondents said they must have or would prefer that their next vehicle comes equipped with a cabin air filter;

* 85 percent of respondents are concerned about the health effects of exhaust gases and vapors while driving; and almost half of the respondents are concerned about pollens, allergens, germs, dust particles, odors and smog;

* 82 percent of the respondents said they would be willing to pay extra for the added value of having a cabin air filter.

"People are taking this issue seriously because it is serious," says Peter Adam, vice president and general manager, Freudenberg Nonwovens, North American Filtration Division, the company that sponsored the survey. "Contaminants inside a car can be up to 10 times more concentrated than outside," he explains, "due to the enclosed space and the 'tunnel effect.' Exhaust gases from the vehicles in front of you are sucked into your car as if you're driving inside a tunnel, which drastically increases the level of unfiltered pollutants inside the cabin."

All-in-all, there are about six to ten suppliers currently offering some type of cabin air filtration system to the automotive market. Today's cabin air filters clean the air entering the passenger cabin of a vehicle through the air conditioning system, reducing certain particulate contaminants that are associated with health concerns such as asthma, shortness of breath, lung tissue damage, cancer, bronchitis, emphysema and influenza.

The technology has come a long way since its earliest introductions in the late 1970s and early 1980s. Primary filters, which were made of unwoven fabric folded into a corrugated shape, had lower filtration efficiency, higher pressure loss and shorter life than today's state-of-the-art air filters. In addition, filtration efficiency was largely improved by adding electrostatic fibers to unwoven fabric.

Electrostatic fibers enabled the filter to remove smaller particles, including submicron diesel particulate matter, explains Shigeki Harada, senior manager overseeing development of air filters for DENSO Corporation. While keeping the high filtration efficiency, the surface structure and shape of fibers were improved to reduce pressure loss of air passing through the filter. The structure of the filter in the air flow direction also was improved to prevent particles from dogging in the filter, thereby lengthening filter life.

Another filter advancement, Harada says, involved adding active carbons to the unwoven fabric. The active carbons expand the filter function from only removing particulate substances to removal of particulate substances as well as harmful gaseous components such as volatile organic compounds (VOC) from the air. VOCs include odor-causing components in emissions and formaldehyde that can cause allergic reactions in some people. Benefits include relief to allergy sufferers by filtering contaminants which can trigger hay fever and other respiratory allergy problems as well as minimizing water-ingress into a vehicle's air conditioning system, which reduces the corrosion, bacterial growth and freezing on HVAC components.

The latest advancement in cabin air filtration are new photo catalytic filters that automatically destroy pollutant gases and microorganisms entering the vehicle. Although some cost and technological concerns remain before these can be adopted widely by the automotive industry, benefits include:

* Continuous protection against potentially harmful external/internal pollutants and discomforting odors;

* Extended service life of filters up to 2,000 hours, which is equivalent to approximately five years average vehicle use; and complete destruction of pollutants.

The reduction of particles and gases entering the vehicle interior is obviously important to maintain the health and safety of passengers, Freudenberg's Adam says. It becomes even more significant when 67 percent of respondents to our study indicated they either suffer from allergies and/or respiratory problems or live with someone who does.