The Airliner Cabin Environment and the Health of Passengers and Crew (2002) / Chapter Skim
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5 Health Considerations Related to Chemical Contaminants and Physical Factors
5 Health Considerations Related to Chemical Contaminants and Physical Factors
Pages 182-222
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From page 182... ...
Among the many plausible explanations of the complaints are the flight environment (e.g., partial pressure of oxygen (PO2) and relative humidity)
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From page 183... ...
Specifically, the reduced ambient air pressure will cause the gas in body cavities (e.g., middle ear, sinuses, an gastrointestinal tract) to expand in volume by as much as 25%.
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From page 184... ...
For healthy adults at sea level, hemoglobin is 95-97°/O saturated. Even at an altitude of 8,000 ft (2,439 m)
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From page 185... ...
these conditions, hemoglobin saturation will be substantially lower than in healthy persons at sea level or in sedentary persons, respectively. For these people, lowering alveolar PO2 by lowering ambient air pressure may also decrease the arterial PO2 and substantially Tower the amount of O2 earned by the blood The ~986 NRC report on airliner cabin environment summarized the effects of altitude on PO2 and recommended that passengers with heart or Jung disease be educated about the risks posed by flight.
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From page 186... ...
Studies conducte during the ~ 940s suggested that the maximal acceptable degree of hypoxia in passenger aircraft corresponded to a cabin altitude of 8,000 ft. but it was recommended that under routine operating conditions cabin pressure altitude should not exceed 5,000-6,000 ft.
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From page 187... ...
Likewise, gas in the respiratory tract and gastrointestinal tract expands and contracts with decreasing and increasing cabin pressure. Although gas readily escapes from those parts ofthe body, minor stomach cramping or bloating might still occur.
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From page 188... ...
Source: Adapted from Delivona-Papadopoulos and Wagerle (1990~. no symptoms in healthy people because hemoglobin remains well saturated with O2 at altitude.
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From page 189... ...
Low relative humidity may cause drying ofthe skin, mucous membranes, and conjunctivae in the latter case adding a risk for conjunctivitis with its symptoms of tearing and pain, especially in those wearing contact lenses (Eng ~ 9791. Studies have indicated that passengers and cabin crews find the air in the aircraft cabin to be too dry and to lead to such symptoms as dry, itchy, or irntated eyes; dry or stuffy noses; and skin dryness or imtation (Lee et al.
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From page 190... ...
They concluded that a modest increase in the relative humidity in an aircraft cabin (e.g., from the current average of ~ 4- ~ 9% to about 22-24%) might have beneficial effects similar to those seen in building studies in which a ~ 0% increase in humidity alleviated many ofthe symptoms of"sick-building syndrome." Such humidities are belong the values that may affect the safety of an aircraft—that is, that might cause condensation in and corrosion of the aircraft sheller that would result in increased microbial growth.
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From page 191... ...
The airplane cabin ozone concentration during flight must be shown not to exceed: (1 ) 0.25 parts per million by volume, sea level equivalent, at any time above flight level 320, and (2)
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From page 192... ...
There were substantial limitations in the study, as discussed in Chapter 6. Engine Oils and Hydraulic Fluids Engine Lubricating oils end hydraulic fluids are complex mixtures of primariTy organic compounds (see Table 3-12 for major components)
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From page 193... ...
Engine lubricating oils contain TCP at 1-5% (typically 3%~. The commercial TCP found in engine oils end hydraulic fluids is actually a mixture of ary~phosphates, including the ortho, meta, end pare isomers and other o-cresol compounds.
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From page 194... ...
An acute oral S-g/kg dose of engine lubricating of] containing 3°/O TCP did not result in any clinical signs of delayed neurotoxicity in hens, the animals most sensitive to the neurotoxic action of TCP and related phosphate esters, after a 3-wk followup period; a repeat oral dose also produced no toxic or histopathological changes (Daughtrey et al 1990~.
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From page 195... ...
~ 965~. For intermittent exposures, groups of six chickens were exposed to hydraulic fluid mist containing ~ .5% TOCP at 25 or 50 mg/m3 for ~ in/d, 5 d/wk, for a total of 30 exposures.
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From page 196... ...
1999~. A recent risk assessment to estimate the potential of conventional and Towtoxicity jet engine oils containing TCP to cause OPIDN found that ingestion of jet engine of} containing 3°/O TCP at approximately 9-10 Ad would be a minimal toxic dose for a 70-kg person; for conventional jet engine oils, the minimal toxic dose was estimated to be 280 mg/kg per day (Mackerer et al.
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From page 197... ...
Skin contact may result in irritation. in summary, the presence of phosphate esters in engine lubricating oils and hydraulic fluids may constitute a potential neurotoxic hazard.
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From page 198... ...
. Measurementofthe airborne concentrations ofthese compounds ormodelingofpossible exposure scenarios in aircraft cabins, with objective demonstration of neurotoxicity in experimental animals exposed to these compounds by inhalation, is needed for a proper assessment of risk.
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From page 199... ...
Fatal COHb concentrations would probably tee Tower at higher altitudes, with reduced PO2, than at sea level. Although CO is known to have fetotoxic effects in laboratory animals, effects on human fetuses are less evident, although of concern.
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From page 200... ...
However, excessive concentrations could be found in aircraft cabins as a result of the thermal decomposition of engine oils or hydrauTic fluids or the reaction of O3 with cabin surfaces. Chapter 3 contains more information on the generation offormaldehyde in cabin air.
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From page 201... ...
human volunteers complained of upper respiratory tract irritation and occasionally of slight headache and low backache. Ethylene glyco]
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From page 202... ...
The disinsection practices of some countries are expected to result in the exposure of cabin crews and passengers to pesticides. Although pyrethroid pesticides have very low toxicity in humans, they can cause adverse effects in some people and are recognized as neurotoxicants at very high doses.
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From page 203... ...
, infants, and children can be more sensitive than healthy adults to the effects of permethrin (Neumann and McLachian ~ 999~. Phenothrin is used to control headlice in children end has been reported to have relatively few adverse health effects (Neumann and McLachian 1 9991.
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From page 204... ...
The synergism is an asset for insect control, but it can have potentially serious implications for humans in the rare event that a leak of engine oils or hydraulic fluids causes these compounds to enter the cabin and causes simultaneous exposure to carboxyesterase inhibitors. No incidents of such interactions have been documented in humans, but engine-oil seal failures and hydraulic-fluid leaks into the ECS of aircraft have been reported (Parliament of Commonwealth ofAustralia 2000; van Netten 2000; van Netten end Leung 2000, 200 ~ )
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From page 205... ...
Concentrations of aldehydes (and ketones) measured in aircraft cabins are "lower than those encountered in ground level buildings" (Nagda et al.
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From page 206... ...
and that limit appears to protect occupants from adverse effects of exposure to CO2. The highest CO2 concentrations measured in aircraft cabins and reported in the literature are below the limit (see Table ~ -2, Chapter ~ )
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From page 207... ...
~ ~m) are the products of combustion of materials such as fuels, engine oil, and hydrauTic and deicing fluids.
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From page 208... ...
Although that assessment may describe the experience of passengers undermost circumstances, problems do occur. Engine oil and hydraulic fluids, and their pyrolysis products, as noted in other chapters, may contaminate the cabin environment, releasing organic compounds, including cresy!
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From page 209... ...
Drying of the nasal mucosa during air travel (due to the low moisture content of the air) may result in nosebleeds =d is thought by some to increase susceptibility to respiratory infections, although this is uncertain (BRE 2001~.
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From page 210... ...
during flights at altitudes of 1,650-2,250 m (about 5,400-7,400 ft) in unpressurized aircraft cabins.
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From page 211... ...
diseases (such as those discussed above) , immune status, and abnormalities in the skin or respiratory tract that allow the entry of infectious agents (Macher and Rosenberg 1999~.
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From page 212... ...
Smokers typically have increased COHb and may have an adaptive response to elevated COHb (EPA 2000~. People with coronary arterial disease and reproducible exercise-induced angina have decreased exercise tolerance at COHb concentrations of 3-6% (EPA 2000~.
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From page 213... ...
· Although Tow relative humidity in the aircraft cabin can result in temporary discomfort as a result of the drying of mucous membranes and eye, nose, and respiratory tract irntation, symptoms are expected to subside after exposure is discontinued. There is no information on the potential forIong- or short-term adverse effects associated with exposure to low relative humidity.
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From page 214... ...
1997. Toxicological Profile for Ethylene Glycol and Propylene Glycol.
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From page 215... ...
2001. Study of Possible Effects on Health of Aircraft Cabin Environments- Stage 2.
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From page 216... ...
Evaluation of Thermal Degradation Products From Aircraft and Automobile Engine Oils, Aircraft Hydraulic Fluid, and Mineral Oil.
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From page 217... ...
1992. Subchronic rat inhalation study with Skydrol 500B-4 fire resistant hydraulic fluid.
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From page 218... ...
2001. Consultation on the Possible Effects on Health, Comfort and Safety on Aircraft Cabin Environments.
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From page 219... ...
2001. Low relative humidity and aircraft cabin air quality.
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From page 220... ...
Report by the Senate Rural and Regional Affairs and Transport References Committee, ParIiament House, Canberra. October 2000.
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From page 221... ...
2001. Hydraulic fluids and jet engine oil: Pyrolysis and aircraft air quality.
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From page 222... ...
1974. Inhalation of aerosolized ethylene glycol byman.
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