The Airliner Cabin Environment and the Health of Passengers and Crew (2002) / Chapter Skim
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7 Air-Quality Measurement Techniques and Applications
7 Air-Quality Measurement Techniques and Applications
Pages 254-275
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From page 254... ...
Atpresent,only air temperature and barometric pressure are routinely measured in commercial aircraft cabins, and only the pressure measurements are recorded as part ofthe flight data. Furthermore, because most flight data recorders retain only data from the most recent 30 min of operation, current recording practices do not permit assessing variations in cabin pressure throughout a flight or, therefore, identifying periods during which partial pressure of oxygen (PO2)
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From page 255... ...
; the resulting concentration is the integrated, or t~rne-weighted average, concentration over the period of sample collection. Air temperature is measured and controlled in all commercial aircraft for the comfort of passengers and crew and to help provide cooling capacity to maintain appropriate operating temperatures for electronic and mechanical equipment.
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From page 256... ...
OZONE To meet the FAA O3 limits, commercial aircraft that fly "high-O3" routes often use devices to remove O3 from the cabin supply air. Such devices are usually catalytic converters, but charcoal adsorption has also been used (SAE 1965; Boeing 2000~.
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From page 257... ...
(See Chapter 3 for a detailed discussion of O3 in aircraft and methods of controlling O3 in aircraft.) Available Technology The feasibility of monitoring O3 in commercial aircraft has been demonstrated in a sampling program launched in ~ 983 by European scientists called Measurement of Ozone and Water Vapor by Airbus In-Service Aircraft (MOZAIC)
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From page 258... ...
258 The Airliner Cabin Environment and the Health of Passengers and Crew TABLE 7-l Simultaneous Ozone Measurements in Supply Air and Outdoor Air on Selected 747 Flights, January-March 1978 Ozone Concentration, ppm Date Routea Supply Air Outside Air 1/25/78 JFK-SFO 0.215 0.471 1/29/78 CHI-IFK 0.380 0.774 2/22/78 CHI-DEN 0.223 0.538 2/25/78 JFK-CHI 0.233 0.643 3/8/78 DEN-CHI 0.280 0.653 3/8/78 CHI-DEN 0.231 0.440 3/12/78 SFO-JFK 0.233 0.528 3/13/78 JFK-CHI 0.236 0.473 3/15/78 CHI-LAX 0.227 0.570 a JFK, New York; SFO, San Francisco; CHI, Chicago; DEN, Denver; LAX, Los Angeles. using commercial long-range aircraft.
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From page 259... ...
(See Chapter 3 for a discussion of retention ratios in Box 3-2.) improved knowledge ofthe magnitude ofthe surface removal rate would also facilitate calculation ofO3 concentrationin the aircraft cabin, given O3 concentration in the supply air and a known air-exchange rate.
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From page 260... ...
, and the American Conference of Governmental Industrial Hygienists (ACGTH) are intended for workplace exposures of healthy adults; they are not intended to apply in situations where infants, children, the elderly, or Lose with pre-existing cardiovascular or pulmonary disease might be exposed.
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From page 261... ...
Electrochemical devices can be operated in the active mode, in which a small air pump draws a continuous sample from the air supply ducts to the sensor via flexible tubing, or in the passive mode, in which the sensor is directly in the air stream to be sampled and the CO enters the sensor by diffusion through a semipermeable membrane (Woebkenberg and McCammon 1995~. CARBON DIOXIDE Except in the case of fire, CO2 floes not pose a health hazard at the concentrations likely to be encountered in commercial aircraft; however, CO2 is a useful surrogate indicator of substandard ventilation of a space with outside air, as has been shown in numerous studies of building-related symptoms (Cain et al.
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From page 262... ...
, the use of indoor air-quality guidelines for CO2 in air might not be appropriate for commercial aircraft. Available Technology Instruments of a size suitable for use in continuous monitoring on aircraft have been developed and used in research investigations (Nagda et al.
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From page 263... ...
To avoid misinterpretation of data because of interference from sublimation of dry ice, it must first tee determined whether air exhausted from the galley is directed overboard and not recirculated. RELATIVE HUMIDITY As described in Chapter 2, moist outside air is dehumidified before it is supplied to the cabin to prevent excessive humidity in the cabin.
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From page 264... ...
PARTICULATE MATTER Continuous Monitoring for Fine Particles Fine particles (particles with diameters of approximately 0.2-2.0 ,um) are generated by combustion and can indicate nonroutine events, such as the pyrolysis of hydraulic fluids and engine oil that have accidentally entered bleed air.
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From page 265... ...
from resuspended dust on carpets, seats, luggage, and occupants' clothing may also be present in the cabin air, they are less efficient in scattering light and will contribute less than the fine particles, per unit mass, to the measured light scattering. Several companies manufacture and distnbute portable nephelometers that could be used to monitor fine-particle concentrations in aircraft cabins.
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From page 266... ...
. A modified version of the MDA sequential sampler might be used that advances the filter tape in response to altimeter readings, with operational temporal segments collected for the following flight segments: · The ground-based phase (boarding of flight crew through aircraft
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From page 267... ...
The methods available to assess the noninhalation routes include analyzing samples removed from aircraft cabin surfaces and from skin and sampling of body fluids or tissues. Surface measuring techniques have recently been r e v i e w e d ( S c h n e i d e r e t a l .
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From page 268... ...
OTHER MONITORING METHODS Many other continuous and integrated monitoring techniques have been used to investigate air quality other than that on commercial aircraft. The techniques include analysis for sulfur, phosphorus, volatile organic compounds (VOCs)
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From page 269... ...
data could alert maintenance personnel to leaking fluid seals, especially at cruise, when no other sources of fine particles are expected. Available Technology With the exception of integrated PM sampling, each instrument type described above has the ability to sample and analyze air for the target contami
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From page 270... ...
~ Although continuous air monitoring has not been implemented, it is technically feasible for a number of air-quality characteristics on commercial aircraft, including temperature, barometric pressure, 03, CO, CO2, relative humidity, and fine PM. Collecting filter samples of suspended PM that could be archived for analysis is also feasible.
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From page 271... ...
. Abbreviations: Bp, barometric pressure; RH, relative humidity.
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From page 272... ...
REFERENCES ACGIH (American Conference of Governmental Industrial Hygienists)
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From page 273... ...
Pp. 1 -18 in Calibration Procedures and Instrumental Accuracy Estimates of Tropical Atmosphere Ocean Temperature, Relative Humidity and Radiation Measurements.
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From page 274... ...
2001. Determine Aircraft Supply Air Contaminants in the Engine Bleed Air Supply System on Commercial Aircraft.
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From page 275... ...
2001. Hydraulic fluids and jet engine oils: Pyrolysis and aircraft air quality.
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