Air quality in aircraft cabins is monitored for levels of carbon monoxide, carbon dioxide, ozone, and airborne particulates for the health and safety of passengers and crew. Researchers from Turkey writing in the International Journal of Sustainable Aviation, point out that volatile organic compounds are not monitored despite the health and other problems that can arise through exposure to some of these substances. In general, however, organic hydrocarbons are not considered worthy of consideration in assessing the atmosphere to which passengers and crew are exposed as a matter of course in an aircraft.
Veli Gokhan Demir and Enver Yalcin of Balikesir University, Ziya Sogut of the Piri Reis University in Instanbul, and Hikmet Karakoc of Eskişehir Technical University have investigated the potential sources of VOCs in an aircraft and what factors might influence concentrations in the air within the passenger and crew areas. Aircraft that fly at high altitude, such as international passenger aeroplanes are pressurized compartments, often with high occupant density, the effects of any volatile pollutants present in the air in this confined, airtight space, could ultimately have a detrimental effect on frequent flyers whether passenger or crew.
One such source of pollutants discussed by the team is from “bleed air”. Air from outside the aircraft is pressurized by the engines and pumped into the interior and recirculated to help maintain an acceptable pressure within. Bleed air can often carry components from engine oil with it. In extreme cases a so-called fume event may occur where concentrations of substances carried in with this bleed air reach uncomfortable levels inside the aircraft. Other VOCs may be present due to reactions with ozone in the aircraft or from other mechanical equipment, such as air conditioning units. Cleaning agents and even cosmetics and perfumes used by occupants can all add to the recirculating load of volatile materials to which all passengers are ultimately exposed during a high-altitude flight.
The team suggests that carbon filtration should be adopted to scrub recirculating air within an aircraft. In addition, there should be dedicated intake vents for bleed air rather than it passing through engines. Given that the presence of ozone can exacerbate the problem of other pollutants because of its reactivity, scrubbers for this compound should also be put in place. An additional factor is to avoid the intake of bleed air during takeoff when ambient pollution from engines and exhaust and service vehicles would compromise air quality for the duration of the flight.
Demir, V.G., Yalcin, E., Sogut, M.Z. and Karakoc, T.H. (2020) ‘Volatile organic compounds in aircraft cabins’, Int. J. Sustainable Aviation, Vol. 6, No. 2, pp.87–111.