Air Quality and Health Effects Associated with the Operation of BAe 146-200 Aircraft

Abstract

Poor air quality and health complaints from flight crews operating BAe-146 aircraft, requiring admission to emergency departments on several occasions, led to an investigation into the source of these problems. Health complaints could be classified as those consistent with exposure to carbon monoxide, respiratory irritants, and possible neurological agents. Cabin air is bled off from the engine's combustion air, passes through a catalytic converter to clean the air from oil contaminants, is cooled from 550° to 50°C, and enters the cabin after it passes through an airpack unit which conditions the air as appropriate. Excessive oil leakage from oil seals overloaded the catalytic converter, allowing smoke and lubricating oil components to enter the cabin. A complaint aircraft air, during a test flight, was found to contain oil contaminants including siloxane lubricating oils, as well as methylated propane and butane ester derivatives. Tricresyl phosphates, known to be neurotoxic, were identified in bulk oil samples, but could not be demonstrated in the cabin air. Air quality measurements in a problem aircraft tested on the tarmac indicated carbon monoxide at 3 ppm and carbon dioxide at 900 ppm. Air quality measurements during normal commercial flights of three noncomplaint aircraft (two BAe-146s and one de Haviland Dash 8-100) showed no detectable levels of carbon monoxide, 800 to 2700 ppm for carbon dioxide, and 19.6 to 21.9 percent for oxygen. Carbon dioxide and oxygen levels would change predictably during takeoff and landing for the former and pressurization and depressurization for the latter. Carboxyhemoglobin levels in four individuals admitted to emergency departments ranged from 0.7 to 2.0 percent. Since no direct carbon monoxide measurements were available during these incidents, it was recommended that potential problem aircraft be equipped with datalogging carbon monoxide monitors to identify or eliminate carbon monoxide exposure as a problem.