cabin air systems

Source: How It Works

APEX Insight: EasyJet is taking action to improve cabin air quality.

The news of easyJet’s plans to outfit its Airbus A320 aircraft with PUREair advanced cabin air filters last September reignited debate on a mysterious condition some believe affects frequent flyers. Aerotoxic syndrome isn’t medically recognized, but since the publication of a scientific paper on the subject in 2000, it’s been the unofficial diagnosis for a catalog of symptoms affecting some air travelers and flight crew: blurred vision, fatigue, nausea, dyspnea, seizures, vomiting, diarrhea and more. These symptoms are generic, so it’s difficult to blame poor cabin air quality directly. However, there could be more to the story.

At the 2017 Cabin Air Conference, Peter Childs, head of the Dyson School of Design Engineering, Imperial College London, presented several ways toxic substances might leak into a cabin’s air supply. Normally, hot bleed air circulates into the aircraft through the jet engines. It then enters the engine compressor for cooling before being recirculated into the air conditioner, where it’s cycled through HEPA (high-efficiency particulate air) filters many times over to cleanse it of impurities before it’s fed into the cabin. Childs says that if this compressor-bleed system is compromised at some stage, it could impact cabin air quality. One concern is the possibility of oil leaking from faulty seals that could pool in different parts of the airplane, like the outer casing, increasing the risk for off-gassing.

Some gases may originate in the cabin itself – from varnish on wood paneling or carpet glue, for example. “However, the majority of these scenarios could be wholly or partially mitigated by use of filtration within a cabin circulation system,” Childs says.

EasyJet’s PUREair filters, manufactured by Pall Aerospace, are built to eliminate odors and VOCs (volatile organic compounds) like organophosphates given off by jet fuel. However, easyJet says the filters are being introduced to “reduce incidents of unusual smell and fumes in the cabin,” which can lead to delayed flights and, on rare occasions, short-term symptoms experienced by passengers on board. Aerotoxic syndrome, it maintains, “remains an area of scientific uncertainty.”

The aerospace industry has been in denial about contaminated cabin air, says Tristan Loraine, a former British Airways captain, who claims toxic cabin air forced him into early retirement in 2006, leading him to start the Global Cabin Air Quality Executive. But easyJet’s acknowledgement of cabin air concerns is a “massive step forward,” he adds.

“Something in the Air” was originally published in the 8.2 April/May issue of APEX Experience magazine.

Fergus Baird is a freelance writer and editor currently living in Montreal. Follow his oddball alter ego on Twitter and Instagram for observations on weird life in the city and beyond.