Contaminated aircraft cabin air

Michaelis, Susan

doi:10.4024/41111/11-4-abs1.jbpc.11.04

Cited by 16 publications

(11 citation statements)

References 36 publications

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“…The reported frequency of fume events varies widely including 2.1 events per 10,000 departures [6], oil fumes in 1% of flights [7] and seals leaking as a function of the design and operation of oil seals reliant upon compressed air [8] [9].…”

Section: Introductionmentioning

confidence: 99%

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Aircraft Clean Air Requirements Using Bleed Air Systems

Michaelis

2018

ENG

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There are certification and airworthiness requirements relevant to the provision of clean breathing air in the crew and passenger compartments. There have been continuing reports and studies over the years regarding oil fumes in aircraft, including impaired crew performance. Oil fumes are viewed in varying ways ranging from rare seal bearing failures, to low level leakage in normal flight. A Masters of Science (MSc) research degree was undertaken to assess whether there is any gap between the certification requirements for the provision of clean air in crew and passenger compartments, and the theoretical and practical implementation of the requirements using the bleed air system. A comprehensive literature search reviewed applicable certification standards, documented and theoretical understanding of oil leakage. Two types of interviews were conducted to address the research questions. Key aviation regulators were questioned about the process by which they certify and ensure compliance with the clean air requirements. Aerospace engineers and sealing professionals were interviewed about their understanding of how oil may leak past compressor oil bearing seals, and into the air supply under various flight conditions. The outcome of the research showed that there is a gap between the clean air certification requirements, and the theoretical and practical implementation of the requirements using the bleed air system. Low level oil leakage into the aircraft cabin in normal flight operations is a function of the design of the engine lubricating system and bleed air systems, both utilising pressurised air. The use of the bleed air system to supply the regulatory required air quality standards is not being met or being enforced as required.

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Section: Introductionmentioning

confidence: 99%

“…Despite recognised under-reporting, crew impairment has been recorded in around 30% of fume event reports [8] [10] [11].…”

Section: Introductionmentioning

confidence: 99%

Aircraft Clean Air Requirements Using Bleed Air Systems

Michaelis

2018

ENG

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“…Exposures of individuals aboard jet aircraft to aerosolized TAPs represent a serious health concern [1, 29, 38, 39]. Because pressurization is necessary for proper engine seal function, exposure to aircraft engine lubricants containing TAPs occurs during “fume events”, engine start-up/shut-down on the ground, and throughout “uneventful” flights during normal acceleration or deceleration [1-3].…”

Section: Discussionmentioning

confidence: 99%

“…Because pressurization is necessary for proper engine seal function, exposure to aircraft engine lubricants containing TAPs occurs during “fume events”, engine start-up/shut-down on the ground, and throughout “uneventful” flights during normal acceleration or deceleration [1-3]. Exposures to aerosolized jet engine lubricants are poorly documented and are often overlooked by airline industries [38].…”

Section: Discussionmentioning

confidence: 99%

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Identifying safer anti-wear triaryl phosphate additives for jet engine lubricants

Baker

Cole

Cartwright

et al. 2013

Chemico-Biological Interactions

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Individuals aboard jet aircraft may be exposed to potentially toxic triaryl organophosphate anti-wear lubricant additives (TAPs) that are converted by cytochromes P450 into toxic metabolites. Consequences of exposure could be reduced by using less toxic TAPs. Our goal was to determine whether an in vitro assay for inhibition of butyrylcholinesterase (BChE) by bioactivated TAPs would be predictive of inhibition of serine active-site enzymes in vivo. The in vitro assay involved TAP bioactivation with liver microsomes and NADPH, followed by incubation with human BChE and measurement of BChE activity. Of 19 TAPs tested, tert-butylated isomers produced the least BChE inhibition. To determine the relevance of these results in vivo, mice were exposed to Durad 125 (D125; a commercial mixture of TAP esters) or to TAPs demonstrating low or no BChE inhibition when assayed in vitro. Inhibition of BChE by bioactivated TAPs in vitro correlated well with inhibition of other serine active-site enzymes in vivo, with the exception of brain acetylcholinesterase and neuropathy target esterase (NTE), which were not inhibited by any TAP tested following single exposures. A recombinant catalytic domain of NTE (rNEST) exhibited classical kinetic properties of NTE. The metabolite of tri-(o-cresyl) phosphate (ToCP), 2-(o-cresyl)-4H-1,3,2-benzodioxaphosphoran-2-one (CBDP), inhibited rNEST in vitro, but with an IC50 value almost 6-times higher than for inhibition of BChE. Physiologically-relevant concentrations of the flavonoid, naringenin, dramatically reduced D125 bioconversion in vitro. The in vitro assay should provide a valuable tool for prescreening candidate TAP anti-wear additives, identifying safer additives and reducing the number of animals required for in vivo toxicity testing.

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Quantitation of ortho‐cresyl phosphate adducts to butyrylcholinesterase in human serum by immunomagnetic‐UHPLC‐MS/MS

et al. 2015

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Tri-ortho-cresyl phosphate (ToCP) is an anti-wear, flame retardant additive used in industrial lubricants, hydraulic fluids, and gasoline. The neurotoxic effects of ToCP arise from the liver-activated metabolite 2-(o-cresyl)-4H-1,3,2-benzodioxaphosphoran-2-one (cresyl saligenin phosphate or CBDP), which inhibits esterase enzymes including butyrylcholinesterase (BChE). Following BChE adduction, CBDP undergoes hydrolysis to form the aged adduct ortho-cresyl phosphoserine (oCP-BChE), thus providing a biomarker of CBDP exposure. Previous studies have identified ToCP in aircraft cabin and cockpit air, but assessing human exposure has been hampered by the lack of a laboratory assay to confirm exposure. This work presents the development of an immunomagnetic-UHPLC-MS/MS method for the quantitation of unadducted BChE and the long-term CBDP biomarker, oCP-BChE, in human serum. The method has a reportable range from 2.0 ng/mL to 150 ng/mL, which is consistent with the sensitivity of methods used to detect organophosphorus nerve agent protein adducts. The assay demonstrated high intraday and interday accuracy (≥ 85%) and precision (RSD ≤ 15%) across the calibration range. The method was developed for future analyses of potential human exposure to CBDP. Analysis of human serum inhibited in vitro with CBDP demonstrated that the oCP-BChE adduct was stable for at least 72 hours at 4, 22 and 37 °C. Compared to a previously reported assay, this method requires 75% less sample volume, reduces analysis time by a factor of 20, and demonstrates a 3-fold improvement in sensitivity.

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Contaminated aircraft cabin air

Cited by 16 publications

References 36 publications

Aircraft Clean Air Requirements Using Bleed Air Systems

Aircraft Clean Air Requirements Using Bleed Air Systems

Identifying safer anti-wear triaryl phosphate additives for jet engine lubricants

Quantitation of ortho‐cresyl phosphate adducts to butyrylcholinesterase in human serum by immunomagnetic‐UHPLC‐MS/MS

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