HECA: Taking school-bus-interior air-cleaning to whole new level

When it comes to mobile air-filtration technology in the school-bus operating environment, HECA could be the next big breakthrough. HECA is up to 88 percent effective when it comes to reducing exposure to pollutants in the air inside school buses, so says Kim Irwin in “On-board school bus filtration system reduces pollutants by 88 percent: UCLA-developed technology would protect children from harmful exposure,” a Mar. 2, 2015 University of California, Los Angeles news release.

The “on-board air filtration system developed specifically for school buses reduces exposure to vehicular pollutants by up to 88 percent, according to a study by researchers at the UCLA Fielding School of Public Health,” Irwin stated.

HECA – what is it?

320px-1970sMNschoolbuses[1]HECA being the acronym for “High Efficiency Cabin Air,” the “system could help protect the 25 million American children who commute on school buses nearly every day. Children are more susceptible to air pollution than adults because they breathe more quickly and their immune and cardiovascular systems are still developing, said Yifang Zhu, the study’s senior author and an associate professor in the department of environmental health sciences.”

As it relates, sitting in congested freeway traffic can result in motor-vehicle occupants being exposed to unusually high concentrations of air-pollutant emissions via vehicle exhaust pipes. It is little if any different regarding children riding school buses. Higher concentrations of said vehicle-exhaust-pollutant-emissions, incidentally, can be present at heavily-trafficked intersections as well.

As for just how well the HECA filtering system performed in terms of helping clean the air in the school bus interiors under test, in certain respects the filtering system performed better than expected, in fact.

Surprising to study researchers was that the greatest pollution reduction was achieved under freeway driving conditions, according to Irwin in the release. And, of particular note, “[t]he study found that the air inside buses with the HECA system was as clean as air near the beach in Santa Monica, California.”

Very relevant, especially taking into consideration the potential for students in urban settings riding school buses to be exposed to unhealthy levels of motor-vehicle-exhaust pollutants when traveling to and from school, and when on field trips and in getting to and from sporting events. Time spent riding school buses, is but another element in the whole pollutant-exposure equation.

“‘Studies have shown that exposure to high levels of vehicle pollution is associated with pulmonary and cardiovascular health risks, including oxidative stress, mitochondrial damage and acute pulmonary inflammation,’ [Zhu] said.” Moreover, there have been other studies that “have also found that children exposed to pollutants from vehicles tend to perform less well in school,” Irwin wrote.

In all, six school buses were tested sans students on board, under idling conditions, and in operating under conditions in which both freeway and major-arterial roadway driving was done – all in Los Angeles. Air was tested for “vehicle-emitted particulate matter, including black carbon and fine and ultrafine particles, down to a few nanometers in size,” inside as well as outside the school buses under test, Irwin reported.

Developed by study researchers was a prototype HECA filtering system specially designed for inside-the-school-bus cabin use and not one but two were placed at the back of each of the half-dozen school buses under evaluation. “Air was drawn in through diffusers on the sides of each unit and fed through the HECA filter,” Irwin wrote. “The filtered air was then delivered at a constant rate through air ducts.”

Brought out in the study also was information that, regarding a filtration system such as HECA, there is great potential to reduce the exposure risk to vehicle-exhaust-pollutant emissions of students riding school buses, according to Irwin.

“A long-term follow-up study will evaluate how much exposure can be reduced by operating the HECA filtration system in a large number of school buses with children aboard, Zhu said,” reported the news release writer.

Image above: David Rees, U.S. Environmental Protection Agency, held and cataloged by the U.S. National Archives and Records Administration

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