The Airliner Cabin Environment and the Health of Passengers and Crew (2002) / Chapter Skim
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3 Chemical Contaminants and Their Sources
3 Chemical Contaminants and Their Sources
Pages 73-130
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From page 73... ...
CONTAMINANTS WITH EXTERNAL SOURCES Ventilation air provided to the cabin by the ECS is drawn from ambient air around the aircraft. Any pollutants in this air can be introduced into the passenger cabin.
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From page 74... ...
Some of the information is summarized in the following paragraphs, but it does not appear to have been used to investigate the effect of emissions at airports on air quality in passenger cabins of aircraft. During the middle 1 980s, the Emissions and Dispersion Modeling System (EDMS)
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From page 75... ...
With respect to pollutant exposure in passenger aircraft cabins at the airport, a key factor is the duration oftime on board while the aircraft is on the ground. Flight attendants have higher potential exposures because they board
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From page 76... ...
Delays on the ground after boarding because of traffic, inclement weather, or equipment malfunction would also be associated with potentially greater exposures. Pollution During Ascent and Descent Ambient air pollution varies markedly with altitude.
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From page 77... ...
. The following subsections review various aspects of O3: atmospheric concentrations that might be encountered on flights, reactivity and possible reactions of O3 with materials present in the passenger cabin, methods of controlling O3 concentrations in passenger aircraft cabins, and studies that have measured O3 concentrations in passenger aircraft cabins.
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From page 78... ...
In the lower troposphere, outdoor air contains only trace amounts of O3 2 The mole fraction is defined as the ratio of the number of moles of a constituent to the total number of moles of air in a given parcel. Therefore, a mole fraction of 1 ppm implies that there is 1 mole of O3 in each million moles of air.
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From page 79... ...
The greater air-exchange rate in an aircraft limits the consequences of homogeneous O3 chemistry. However, the potentially high O3 concentrations in aircraft cabins compared with ordinary buildings somewhat offset the effect of faster air exchange.
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From page 80... ...
The table indicates that the reactions of O3 with a7-limonene and a-pinene are fast enough to compete with cabin air exchange under conditions of high cabin O3. Although the high ventilation rates on aircraft limit the time available for gas-phase (homogeneous)
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From page 81... ...
Therefore, although the increased ventilation rates favor the formation of reaction products, the greater production rate is offset by a greater dilution rate. Higher ventilation rates can lead to the accumulation of semivolatile products of heterogeneous O3 chemistry on surfaces depending on their vapor pressure and rate of volatilization.
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From page 82... ...
82 The Airliner Cabin Environment and the Health of Passengers and Crew
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From page 83... ...
Two regulations introduced in ~ 980 established O3 concentration limits for aircraft cabins (FAR 25.832 and FAR 121 .5784. The regulations are discussed in Chapter I, and the regulatory language is in Appendix C
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From page 84... ...
. As discussed in Chapter 2, the use of O3 converters is the only active treatment technology commonly used for reducing O3 concentrations in aircraft passenger cabins.
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From page 85... ...
Chemical Contaminants and Their Sources 85
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From page 86... ...
Of particular concern is the potential for fouling caused by an air-quality incident. For example, any sizable exposure ofthe breed-air system to engine Lubricating oil, hydraulic fluid, orevenjet exhaust could contribute to fouling that would degrade the performance (de
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From page 87... ...
A lower destruction efficiency could lead to exceeding the regulatory limit. Specifically, a 95°/O O3 destruction efficiency appears to be sufficient to maintain cabin O3 below regulatory limits, but a 50% destruction efficiency would not suffice (see Box 3-3~.
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From page 88... ...
photometric and chemiTuminescence instruments have sufficient sensitivity and accuracy to measure O3 reliably and accurately in the concentration range of interest. Furthermore, only UV photometric instruments are acceptable aboard aircraft because chemiTuminescence instruments use a combustible consumable (ethyI
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From page 89... ...
~ ppm. Although the study suggests that average~O3 in aircraft cabins is Tow, the committee has several concerns regarding the study and believes that general 3The investigators did not report-whether the difference between the smoking and nonsmoking~flights was statistically significant.
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From page 90... ...
The authors of the DOT study concluded, on the basis of their O3 measurements, that "all values were consistently below flight, occupational, and environmental standards by the Federal government.... This and current scientific knowledge leads to the conclusion that ozone does not pose a health hazard to cabin crew members or passengers."
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From page 91... ...
Measure- ~ meets in aircraft passenger cabins were made on four flight segments in 1996. Integrated average O3 concentrations were "consistently below the limit of detection for the method used (i.e., 1.8 to 9.8 ppb)
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From page 92... ...
The reported maximum of 3 times that suggests a converter efficiency of approximately 85%. Finally, a substantial study of air quality in aircraft cabins is in its late stages.
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From page 93... ...
Therefore, the potential for high O3 in aircraft cabins remains a concern. A program of regular monitoring of cabin 03, particularly on highaltitude, high-latitude flights, is necessary to document the effectiveness of control measures.
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From page 94... ...
Bioeffluent emission rates are presented in Table 3-5 for several common compounds as prepared by the NRC Subcommittee on Guidelines for Developing Spacecraft Maximum Allowable Concentrations (SMACs) for Space Station Contaminants (NRC 992~.
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From page 95... ...
Miscellaneous Hydrogen Ammonia Carbon monoxide Carbon dioxide 1.42 4.00 1.20 1.33 0.08 0.83 600.00 0.13 0.83 0.83 0.83 208.30 0.83 9.17 25.00 25.00 50.00 250.00 33.30 8.8 x 105 b a IUPAC or accepted name is provided with common name in parentheses, where relevant. b Estimate based on generation rate of 0.31 L/min, which was used by ASHRAE to determine ventilation standards (ASlIRAE 1999~.
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From page 96... ...
96 o cn 4 o a' U
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From page 97... ...
97 _ ~ _ oo 1 1 1 1 1 1 1 ~ ~ ~ ~ ~ 0 ~ _ ~ _ ~t 1 1 1 1 ~ 0 ~ ~ ° ~ t— t— _ ~ _ _ ~ _ ~ _ ~ ~ q _ ~ ~ ~ ~ ~ In ~ 0 ~ ~ 0 ~ _ c%1 — ~ ~ ~ - , ~ ~ oo ~ ~ _ 1 1 1 1 1 1 1 1 1 1 1 _ 0 ~ ~ 0 _ _ oo 0 1 1 1 1 ~ 0 ~ 0 1 1 1 1 0 0 ~ ~ 0 ~ ~ ~ ~ ~ :S ° ~ 2 & ~ c =0 , ~ O — ~ ~ Aft ~: ~ a ~ ,,, .
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From page 98... ...
Fabric seat and floor coverings, like other commercial materials, may be treated with stainresistant and antifungal-antibacterial chemicals. Although the potential for exposure to these coating materials exists, no published data were available to determine the extent or degree of exposure of passengers and crew to these materials.
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From page 99... ...
Although the experimental conditions used by Fang and co-workers do not extend to the Tow humidity range experienced on commercial aircraft, their results suggest why passengers and crew may be able to distinguish specific odors in the dry air of aircraft that cause them concern regarding air quality. Cleaning Materials and Dust The interiors of aircraft are cleaned between flights.
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From page 100... ...
65 75 FIGUR=. 3 Acceptability of air samples with different pollutant loadings versus clean air as function of enthalpy.
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From page 101... ...
The disinfectant category TABLE 3-7 Components or Constituents of Cleaning Agents Component or Constituent Examples ., Volatile Substances Fragrance Solvent Biocide (disinfectant) Plasticizer (softener)
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From page 102... ...
, or Corrosive (C) and Content of CRANa Substances in Selected Danish Cleaning Agents Number of Products Classified Classified as Number of CRAN Products Substances in Product Category (%)
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From page 103... ...
In addition, airplane dust can include residues from cleaning agents and pesticides (see discussion below)
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From page 104... ...
The indoor airborne-particle concentrations were lower by more than 20 ~g/m3 in the intervention group.
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From page 105... ...
In airport malaria, a person contracts malaria from an infected mosquito transported on an aircraft from a malarious region; in runway malaria, a person contracts malaria during a stopover in a region where malaria
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From page 106... ...
South Africa (areas of malaria or yellow fever) Madagascar Jamaica (residual treatment)
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From page 107... ...
Chemical Cor~taminar~ts and Their Sources ~ 07 TABLE 3-10 Countries in Which Confirmed or Probable Cases of Airport Malaria Have Been Reported, 1969-August ~ 999 l Period Country 1969-77 1978-86 1987-95 1996-98 1999 Total France 9 3 11 3 — 26 Belgium 0 9 7 1 17 Switzerland 3 0 5 1 ~ 9 United Kingdom 4 3 0 7 14 Italy 0 1 3 0 4 USA 0 0 3 1 4 Luxembourg 2 3 5 O 0 2 1 1 4 0 2 0 0 — 2 Spain 0 1 1 0 2a Israel 0 0 0 1 1 Australia 0 0 0 1 1 Total _ a Original table mistakenly reported zero. Source: Gratzet al.
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From page 108... ...
WHO ( l 995) commented that "Member States should limit any routine requirement for disinsection of aircraft cabins and flight decks with an aerosol, while passengers are onboard, to aircraft operations originating in, or operating via, temtories that they consider to pose a threat to their public health, agnculture or environment." Residual treatment and pre-embarkation spraying are similar in that no passengers are on board while the spraying is conducted.
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From page 109... ...
The preflight application often used in conjunction with the procedures noted is typically a 2% permethrin formulation. For residual treatment, a 2% aqueous emulsion of permethrin is typically applied at 10 mL/m2 and aimed to deliver permethrin at a rate of 0.2 g/m2, a higher application rate maybe required for carpets.
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From page 110... ...
The stages at which air is bled from the system depend on the aircraft and the flight segment. Bleed air can also be supplied by the APU,
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From page 111... ...
Chemical Contaminants and Their Sources ~ ~ ~
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From page 112... ...
~ ~ 2 The Airliner Cabin Environment and the Health of Passengers and Crew leaks do occur is supported by information provided in the Boeing 737 maintenance manual, which describes how air can become contaminated and how to purge contaminants from the system (Boeing ~ 998~. Specifically, the manual indicates that "smoke or fumes" may enter "the passenger cabin or the flight compartment through the air distribution system during flight." The problems
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From page 113... ...
Although information on the composition of engine lubricating oils and hydraulic fluids is useful, it does not positivelyidentify components that would be present in bleed air as a result of equipment failures. Laboratory experiments have been conducted to determine constituents that might be generated when engine lubricating oils and hydraulic fluids are exposed to high temperatures (i.e., 525°C)
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From page 114... ...
CAS No. Engine lubricating oils Mobil jet oil 254 Tricresyl phosphate (1 -5%)
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From page 115... ...
The foregoing discussion focused on potential contaminants in bleed air during an air-quality incident. Another issue to address is the quality of bleed air during normal operating conditions.
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From page 116... ...
~ ~ 6 The Airliner Cabin Environment and the Health Passengers and Crew
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From page 117... ...
No TCP isomers, including TOCP, were detected, and no TMPP was detected. On the basis of data obtained in this investigation, the authors rated the quality ofthe bleed air as high under normal operating conditions.
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From page 118... ...
(2001~. they noted that only ~ O flights were monitored, end these flights "do not provide a statistically robust sample for representing the universe of all flights." Other fluids that can potentially enter an aircraft ventilation system are deicing fluids.
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From page 119... ...
Although data on exposure to other contaminants in aircraft cabins are extremely sparse, there are some data on CO2, CO, PM, VOCs, and SVOCs under normal operating conditions. CO2 concentrations appear to be below the FAA regulatory limit, although often higher than the ASHRAE ventilation standard; CO and PM concentrations appear to be lower than health-based standards for ambient air; and VOC and SVOC concentrations appear to be similar to those in other public-transport vehicles.
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From page 120... ...
are released from engine lubricating oils and hydraulic fluids into the ambient air, where they can be measured at room temperature. However, the components released into the passenger cabin during air-quality incidents and their possible concentrations cannot be determined from the expenments.
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From page 121... ...
1999. ASHRAE Standard - Ventilation for Acceptable Indoor Air Quality.
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From page 122... ...
20. 1-20.21 in Indoor Air Quality Handbook, J.D.
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From page 123... ...
1998. Indoor air quality: recommendations relevant to aircraft passenger cabins.
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From page 124... ...
Pp.64.1 -64.18 in Indoor Air Quality Handbook, J.D. Spengler, J.M.
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From page 125... ...
2001. Detennine Aircraft Supply Air Contaminants in the Engine Bleed Air Supply System on Commercial Aircraft.
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From page 126... ...
1989. Ventilation rates in office buildings.
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From page 127... ...
Vuorelma, eds. Helsinki: Intemational Society of Indoor Air Quality and Climate (ISIAQ)
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From page 128... ...
2000. Analysis of two jet engine lubricating oils and a hydraulic fluid: their pyrolytic breakdown products and their implication on aircraft air quality.
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From page 129... ...
1996. Production of the hydroxyl radical in indoor air.
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From page 130... ...
Sateri, eds. Helsinki, Finland: SIY Indoor Air Information.
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