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PubMedDate not supplied

Aircraft cabin air recirculation and symptoms of the common cold.

CONTEXT: In recent years, new commercial aircraft have been designed to recirculate approximately 50% of the cabin air to increase fuel efficiency. Some older aircraft use only fresh air. Whether air recirculation increases the transmission of infectious disease is unknown; some studies have demonstrated higher rates of the common cold among persons working in buildings that recirculate air. OBJECTIVE: To evaluate the role of air recirculation as a predictor of postflight upper respiratory tract infections (URIs). DESIGN, SETTING, AND PARTICIPANTS: A natural experiment conducted among 1100 passengers departing the San Francisco Bay area in California and traveling to Denver, Colo, during January through early April 1999, and who completed a questionnaire in the boarding area and a follow-up telephone interview 5 to 7 days later. Forty-seven percent traveled aboard airplanes using 100% fresh air for ventilation, and 53% traveled aboard aircraft that recirculated cabin air. MAIN OUTCOME MEASURE: Incidence of reporting new URI symptoms within 1 week of the flight. RESULTS: Passengers on airplanes that did and did not recirculate air had similar rates of postflight respiratory symptoms. The rates of reporting a cold were 19% vs 21% (P =.34); a runny nose and a cold, 10% vs 11%, (P =.70); and an aggregation of 8 URI symptoms, 3% in both groups (P>.99). Results were similar after statistical adjustment for potential confounders. CONCLUSION: We found no evidence that aircraft cabin air recirculation increases the risk for URI symptoms in passengers traveling aboard commercial jets.

Adult↗
PubMed1993

Effects of aircraft noise on hearing and auditory pathway function of school-age children.

This study was conducted to investigate the influence of high-frequency aircraft noise on the function of the auditory system of school-age children. A total of 228 students attending a school near an airport (school A) and 151 students attending a school far from an airport (school B) were analyzed. Audiometry and brainstem auditory evoked potential (BAEP) detection were performed in all subjects to evaluate cochlear and retrocochlear function. The results of audiometry indicated that hearing ability was significantly worse in the children of school A, which was located under the flight paths. The values of pure tone average, high pure tone average, and threshold at 4 kHz were all higher in children who were frequently exposed to aircraft noise. There was no consistent difference in BAEP latencies between the two schools. These results indicate that central transmission is not affected in children who have been exposed to aircraft noise for several years. The results of the present study showed a significant association between aircraft noise exposure and prevalence of noise-induced hearing loss. Although damage to peripheral cochlear organs was confirmed in school-age children, involvement of the central auditory pathway could not be verified.

Aircraft↗
PubMed2005

Aircraft disinsection: exposure assessment and evaluation of a new pre-embarkation method.

A new "pre-embarkation" method for aircraft disinsection was investigated using two different 2% d-phenothrin containing aerosols. Five experiments in aircrafts of the type Airbus 310 (4x) and Boeing 747-400 (1x) were performed. In the absence of passengers and crew the d-phenothrin aerosol was sprayed under the seat rows and in a second step at the height of approximately 1.60 m by moving from one end of the cabin to the other. Concentration levels of d-phenothrin were determined at different time periods after application of the aerosol spray. In a B 747-400 with the air conditioning system operating the concentrations ranged between 853 and 1753 microg/m3 during and till 5 min after the beginning of spraying at different locations in the cabin. Within 5-20min after the end of the spraying concentrations of 36-205 microg/m3 and 20-40 min thereafter only ca. 1 microg d-phenothrin/m3 were detectable (average values in relation to each period of measurement). On cabin interior surfaces the median values for mainly horizontal areas ranged from 100 to 1160 ng d-phenothrin/cm2. d-Phenothrin concentrations in the air were sufficient to kill flying insects like house flies and mosquitoes within 20 min. Horizontal surfaces were 100% effective against insects up to 24 h after spraying. Doses inhaled by sprayers determined by personal measurements were calculated to be 30-235 microg d-phenothrin per 100 g spray applied (30% in the respirable fraction for Arrow Aircraft Disinsectant; 10% for Aircraft Disinsectant Denka). If passengers will board, e.g., 20 min after the end of the disinsection operation, inhalation exposure is estimated to be practically negligible. Also possible dermal exposure from residues in seats and headrests is very low for passengers during the flight. Therefore any health effects for passengers and crew members are very unlikely.

Aedes↗
PubMed2005

Plaster cast immobilisation during air travel-analysis of current practice and aircraft-simulated experimental study.

BACKGROUND: There is an increase in aircraft transportation of patients with lower limb fractures. Current practice is variable. Our aim was to study current practice and to analyse the situation in an experimental simulated aircraft flight. METHODS: Current advice supplied by commercial airline offices in the UK was noted. Postal questionnaires were sent to Orthopaedic Consultants in the UK to obtain their current practice. Experimental aircraft travel was simulated in a decompression chamber with five medically fit volunteers with no fracture, immobilised in an above knee plaster cast. Compartment pressure and venous return was documented and the results analysed in two different positions with the leg elevated and dependant. RESULTS: Airlines do not have any formal guidelines. Orthopaedic consultants in the UK note variable advise in this situation. Experimental study in the aircraft simulation showed that two volunteers developed significant increase in compartmental pressure with the leg elevated to 90 degrees , which settled after the plaster cast was split. There was no increase in compartment pressure noted with leg dependant on the floor with 45 degrees of flexion at hip. CONCLUSION: The literature on this issue is limited. With our analysis we feel that patients can be transported with the plaster cast split with limb dependant on the floor i.e. hip flexion less than 45 degrees . Our volunteers had no fractures so direct comparison with pathological changes in acute fracture is problematical. Further studies into this problem are recommended.

Adult↗
PubMed1996

Atmospheric cosmic rays and solar energetic particles at aircraft altitudes.

Galactic cosmic rays, which are thought to be produced and accelerated by a variety of mechanisms in the Milky Way galaxy, interact with the solar wind, the earth's magnetic field, and its atmosphere to produce hadron, lepton, and photon fields at aircraft altitudes that are quite unlike anything produced in the laboratory. The energy spectra of these secondary particles extend from the lowest possible energy to energies over an EeV. In addition to cosmic rays, energetic particles, generated on the sun by solar flares or coronal mass ejections, bombard the earth from time to time. These particles, while less energetic than cosmic rays, also produce radiation fields at aircraft altitudes which have qualitatively the same properties as cosmic rays. The authors have calculated atmospheric cosmic-ray angular fluxes, spectra, scalar fluxes, and ionization, and compared them with experimental data. Agreement with these data is seen to be good. These data have been used to calculate equivalent doses in a simplified human phantom at aircraft altitudes and the estimated health risks to aircraft crews. The authors have also calculated the radiation doses from several large solar energetic particle events (known as GLEs, or Ground Level Events), which took place in 1989, including the very large event known as GLE 42, which took place on September 29th and 30th of that year. The spectra incident on the atmosphere were determined assuming diffusive shock theory. Unfortunately, there are essentially no experimental data with which to compare these calculations.

Aerospace Medicine↗
PubMed2003

Radiation measurements aboard NASA ER-2 high altitude aircraft with the Liulin-4J portable spectrometer.

The risks to aircrew health posed by prolonged exposure to low levels of ionizing radiation at aircraft altitudes have recently received renewed attention. Civil and military aircraft currently on the drawing board are expected to operate at higher altitudes (>12 km) and fly longer ranges than do existing aircraft, thereby exposing their crews to higher levels of ionizing radiation, for longer periods of time. We are currently carrying out dosimetric measurements of the ionizing radiation environment at approximately 20 km altitude using portable Si detectors aboard NASA's two ER-2 high altitude research aircraft. The instruments, Liulin-4J, have been extensively calibrated at several particle accelerators. With these instruments, we can measure not only absorbed dose, but also variation of the absorbed dose as a function of time. We report radiation dose measurements as function of time, altitude, and latitude for several ER-2 missions.

Aircraft↗
PubMed2003

Laser in situ keratomileusis in a combat jet aircraft pilot.

Pilots who have had laser in situ keratomileusis (LASIK) surgery are disqualified from flying status in a combat jet aircraft in the United States Navy and Air Force. We report the case of a jet aircraft pilot who had LASIK for myopia. The pilot resumed flights 2 weeks after the procedure and has performed several dozen uneventful daylight flights in a combat jet aircraft. We recommend a clinical study to reevaluate the appropriateness of LASIK in military jet aircraft aviation.

Adult↗
PubMed1992

Transporting the family and other concerned parties aboard air medical aircraft.

Patients flown on air medical aircraft are separated from family and other concerned parties, often for several hours and many miles. This paper studies the usefulness and safety of offering transport to these passengers on air medical aircraft. A nine-item questionnaire was mailed to 95 program directors. Only those air medical operations flying aircraft with the capability of carrying additional personnel were targeted. These aircraft included all fixed-wing craft; the helicopters included Bell 222, MBB BK 117, Sikorsky S-76, and Aerospatiale SA 365 Dauphin. Seventy responses were received. From these responses it was concluded that more than half of all helicopter programs can carry a patient's family, but do so only 5% of the time. All fixed-wing programs can carry family of patients and do so from 35% to 95% of the time. Various benefits and disadvantages were discovered, analyzed, and discussed.

Aircraft↗
PubMedDate not supplied

Aircraft noise, hearing ability, and annoyance.

The relationship between aircraft noise, loss of hearing, and annoyance was explored in a study in two schools located near an international airport in Taiwan. Sixth-grade students (N = 242) were recruited from two schools and were classified into high- and low-noise-exposure groups, based on environmental noise measurements. Personal-equivalent 24-h noise exposure was measured to determine noise exposure at the individual level, and it was compared with hearing threshold level and with aircraft noise measured at the environmental level. Individual hearing threshold levels did not differ between environmental high- and low-noise-exposure groups, as evidenced by the lack of difference between the two groups for noise exposure measured at the individual level. However, the proportion of students who were annoyed by aircraft noise was higher in the environmental high-noise-exposure group, although personal 24-h noise exposure was not a factor for annoyance. The results indicated that environmental noise measurement was not an appropriate criterion for assessment of auditory damage (or noise-induced hearing loss) in Taiwan. As well, aircraft-noise exposure in Taiwan did not appear to affect the hearing threshold but nonetheless annoyed schoolchildren near the airport.

Aircraft↗
PubMed2001

Landfills, nocturnal foraging, and risk to aircraft.

Open landfills serve as an attractant to birds, with increasing risk of bird-plane collisions. Managers are searching for methods to allow landfilling while reducing potential bird problems near airports. Some municipalities are considering nighttime landfilling as an avian deterrent, particularly where waste management facilities are located near airports. The objective of this report was to evaluate whether nighttime landfilling will result in increased risk to aircraft from birds at the Atlantic County Airport in coastal New Jersey. The risk to nearby aircraft from nighttime landfill is a function of (1) attractiveness of landfills, airports, or other habitats, (2) nocturnal behavior of gulls and other birds, (3) elevations and flight paths of birds, (4) changes in population levels of gulls and other potentially hazardous birds, and (5) harassment techniques that can deter birds from the landfills, adjacent habitat, and airports. The latter, however, can serve to move birds to locations or altitudes that pose an even greater risk to aircraft. The number of strikes is generally increasing. While most air strikes occur during the day at the Atlantic County Airport, over 12% occur at night and nearly 20% occur at dawn when any garbage remaining from nighttime landfilling would be an attractant. The peak of strikes occurs in the early fall, when young birds are learning to forage. Risk data suggests that gulls and a wide variety of other birds are active at night, and if any garbage is available they will be attracted, increasing the risk to aircraft landing at night. Some actual night dumping has been carried out since October 3 1997 without apparently attracting gulls, suggesting that careful operations with appropriate institutional controls can make nighttime dumping feasible.

Aircraft↗
PubMed2004

Radiation protection aspects of the cosmic radiation exposure of aircraft crew.

Aircraft crew and frequent flyers are exposed to elevated levels of cosmic radiation of galactic and solar origin and secondary radiation produced in the atmosphere, the aircraft structure and its contents. Following recommendations of the International Commission on Radiological Protection in Publication 60, the European Union introduced a revised Basic Safety Standards Directive, which included exposure to natural sources of ionising radiation, including cosmic radiation, as occupational exposure. The revised Directive has been incorporated into laws and regulations in the European Union Member States. Where the assessment of the occupational exposure of aircraft crew is necessary, the preferred approach to monitoring is by the recording of staff flying times and calculated route doses. Route doses are to be validated by measurements. This paper gives the general background, and considers the radiation protection aspects of the cosmic radiation exposure of aircraft crew, with the focus on the situation in Europe.

Aircraft↗
PubMed2004

Annoyance with aircraft noise in local recreational areas, contingent on changes in exposure and other context variables.

Few socioacoustic studies have examined the effect of noise on outdoor recreationists. The areas studied have been mountain and wilderness areas that people typically travel for a distance to visit. In this article we examine the reactions to aircraft noise in local recreational areas experiencing either decreased (1930 survey respondents), or increased noise exposure (1001 survey respondents). Field studies were conducted before and after the relocation the main airport of Norway in 1998 in one area near each airport. The relationship between individual noise exposure (LAeq for the aircraft events, percentage of time aircraft were audible, and LAsel) for the aircraft events. The analyses included the "situation" in which data were collected (before or after the relocation), and variables describing the recreational context. A strong effect of the "situation" was found in both cases, but the size of the effect was influenced by the choice of exposure variable in one of the study areas. Other context variables were also influencing annoyance. The effect of the situation (before/after a change in exposure) on the dose-response relationship may be influenced by the initial noise levels, the amount of change, and the time elapsed since the change at the time of the second survey. Further research should investigate the significance of these variables.

Adolescent↗
PubMed2006

Aircraft noise effects on sleep: application of the results of a large polysomnographic field study.

The Institute of Aerospace Medicine at the German Aerospace Center (DLR) investigated the influence of nocturnal aircraft noise on sleep in polysomnographic laboratory and field studies between 1999 and 2004. The results of the field studies were used by the Regional Council of Leipzig (Germany) for the establishment of a noise protection plan in the official approval process for the expansion of Leipzig/Halle airport. Methods and results of the DLR field study are described in detail. Special attention is given to the dose-response relationship between the maximum sound pressure level of an aircraft noise event and the probability to wake up, which was used to establish noise protection zones directly related to the effects of noise on sleep. These protection zones differ qualitatively and quantitatively from zones that are solely based on acoustical criteria. The noise protection plan for Leipzig/Halle airport is presented and substantiated: (1) on average, there should be less than one additional awakening induced by aircraft noise, (2) awakenings recalled in the morning should be avoided as much as possible, and (3) aircraft noise should interfere as little as possible with the process of falling asleep again. Issues concerned with the representativeness of the study sample are discussed.

Acoustics↗
PubMed1999

Mortality among aircraft manufacturing workers.

OBJECTIVES: To evaluate the risk of cancer and other diseases among workers engaged in aircraft manufacturing and potentially exposed to compounds containing chromate, trichloroethylene (TCE), perchloroethylene (PCE), and mixed solvents. METHODS: A retrospective cohort mortality study was conducted of workers employed for at least 1 year at a large aircraft manufacturing facility in California on or after 1 January 1960. The mortality experience of these workers was determined by examination of national, state, and company records to the end of 1996. Standardised mortality ratios (SMRs) were evaluated comparing the observed numbers of deaths among workers with those expected in the general population adjusting for age, sex, race, and calendar year. The SMRs for 40 cause of death categories were computed for the total cohort and for subgroups defined by sex, race, position in the factory, work duration, year of first employment, latency, and broad occupational groups. Factory job titles were classified as to likely use of chemicals, and internal Poisson regression analyses were used to compute mortality risk ratios for categories of years of exposure to chromate, TCE, PCE, and mixed solvents, with unexposed factory workers serving as referents. RESULTS: The study cohort comprised 77,965 workers who accrued nearly 1.9 million person-years of follow up (mean 24.2 years). Mortality follow up, estimated as 99% complete, showed that 20,236 workers had died by 31 December 1996, with cause of death obtained for 98%. Workers experienced low overall mortality (all causes of death SMR 0.83) and low cancer mortality (SMR 0.90). No significant increases in risk were found for any of the 40 specific cause of death categories, whereas for several causes the numbers of deaths were significantly below expectation. Analyses by occupational group and specific job titles showed no remarkable mortality patterns. Factory workers estimated to have been routinely exposed to chromate were not at increased risk of total cancer (SMR 0.93) or of lung cancer (SMR 1.02). Workers routinely exposed to TCE, PCE, or a mixture of solvents also were not at increased risk of total cancer (SMRs 0.86, 1.07, and 0.89, respectively), and the numbers of deaths for specific cancer sites were close to expected values. Slight to moderately increased rates of non-Hodgkin's lymphoma were found among workers exposed to TCE or PCE, but none was significant. A significant increase in testicular cancer was found among those with exposure to mixed solvents, but the excess was based on only six deaths and could not be linked to any particular solvent or job activity. Internal cohort analyses showed no significant trends of increased risk for any cancer with increasing years of exposure to chromate or solvents. CONCLUSIONS: The results from this large scale cohort study of workers followed up for over 3 decades provide no clear evidence that occupational exposures at the aircraft manufacturing factory resulted in increases in the risk of death from cancer or other diseases. Our findings support previous studies of aircraft workers in which cancer risks were generally at or below expected levels.

Aircraft↗
PubMed2001

The possible effects on health, comfort and safety of aircraft cabin environments.

A consultation was undertaken to investigate the views and concerns of stakeholders in the aircraft industry about the possible harmful effects on personal health, comfort and safety of aircraft cabin environments. Stakeholders were identified from a variety of sources including Government agencies, the Internet, House of Lords inquiry, and suggestions of interviewees. They represented: aircraft crews, aircraft constructors and engineers, government departments and authorities, holiday/flight companies, insurance companies, non-governmental organisations, occupational health physicians, passenger representatives, and independent researchers and consultants. Eighty-seven were contacted of which 57 were interviewed over the telephone using a semi-structured questionnaire. Their concerns were transcribed into a standard format and analysed qualitatively. Key stakeholders, along with Government officials, were invited to a workshop to discuss and prioritize the issues raised during the interviews. The main concerns expressed by the participants fell into five main areas: deep vein thrombosis, air quality, infection, cosmic radiation, and jet lag and work patterns. In addition, a number of safety concerns were raised as well as comments on the provision of appropriate advice to passengers. It was generally felt that further research was required on each of these subjects, as well as an improvement in the quality, quantity and availability of information provided for passengers prior to boarding a flight.

Air Pollution, Indoor↗
PubMed2000

Real-time and integrated measurement of potential human exposure to particle-bound polycyclic aromatic hydrocarbons (PAHs) from aircraft exhaust.

We used real-time monitors and low-volume air samplers to measure the potential human exposure to airborne polycyclic aromatic hydrocarbon (PAH) concentrations during various flight-related and ground-support activities of C-130H aircraft at an Air National Guard base. We used three types of photoelectric aerosol sensors (PASs) to measure real-time concentrations of particle-bound PAHs in a break room, downwind from a C-130H aircraft during a four-engine run-up test, in a maintenance hangar, in a C-130H aircraft cargo bay during cargo-drop training, downwind from aerospace ground equipment (AGE), and in a C-130H aircraft cargo bay during engine running on/off (ERO) loading and backup exercises. Two low-volume air samplers were collocated with the real-time monitors for all monitoring events except those in the break room and during in-flight activities. Total PAH concentrations in the integrated-air samples followed a general trend: downwind from two AGE units > ERO-loading exercise > four-engine run-up test > maintenance hangar during taxi and takeoff > background measurements in maintenance hangar. Each PAH profile was dominated by naphthalene, the alkyl-substituted naphthalenes, and other PAHs expected to be in the vapor phase. We also found particle-bound PAHs, such as fluoranthene, pyrene, and benzo[a]pyrene in some of the sample extracts. During flight-related exercises, total PAH concentrations in the integrated-air samples were 10-25 times higher than those commonly found in ambient air. Real-time monitor mean responses generally followed the integrated-air sample trends. These monitors provided a semiquantitative temporal profile of ambient PAH concentrations and showed that PAH concentrations can fluctuate rapidly from a baseline level < 20 to > 4,000 ng/m(3) during flight-related activities. Small handheld models of the PAS monitors exhibited potential for assessing incidental personal exposure to particle-bound PAHs in engine exhaust and for serving as a real-time dosimeter to indicate when respiratory protection is advisable.

Air Movements↗
PubMed2002

Laser projection versus a CRT display in the visual perception of aircraft aspect.

High-resolution visual displays have been designed for flight simulation so that observers may judge the aspect angle of aircraft at far distances. The present experiment compares two display devices as untrained observers judge the spatial orientation of two target aircraft: F-15 and F-16 jets. The display devices are a prototype direct-write microlaser projector and an SXGA-format CRT display. Observers' accuracy of aircraft identification is better with the laser projector, and recognition response times are faster. A simple rule was found to fit the observers' response times; it is expressed in terms of a statistic on the autocorrelation of black-and-white silhouette images of aircraft. Observers' estimates of aspect are biased by the laser projector, whereas observers' estimates of aspect are accurate on average with the SXGA display. This bias in estimation of aspect may be attributable to variations in line brightness introduced by the laser projector. Actual or potential applications of this research include the evaluation of high-resolution visual displays for the training of basic fighter maneuvers with military jet pilots.

Aircraft↗
PubMed2006

Prevention of mosquitoes (Diptera: Culicidae) and house flies (Diptera: Muscidae) from entering simulated aircraft with commercial air curtain units.

Commercially available air curtain units were used to create air barriers to prevent mosquitoes and house flies from entering a simulated aircraft doorway together with passengers. Two assemblies of simulated passenger bridge and aircraft were constructed, and airflow measurements were recorded to confirm airflow characteristics for several combinations of commercial units. Three mosquito species were selected for different host-seeking characteristics, and house flies were selected to represent a large, strong-flying insect. Batches of 20 or 200 insects of four species were released into the passenger bridge just before 25 persons passed through the assembly, then insects that entered the aircraft cabin were recovered. Results showed that horizontal plus vertical or vertical-mounted air curtain units with the airflow directed at a 45 degrees angle into the passenger bridge excluded 95-99% of the mosquitoes and 95-100% of the house flies, respectively. Airflows were measured and estimated to be effective if the mean was > 4 m/s in the critical area in the center of the converging airflows. The study validates the concept that air barriers can effectively prevent the passage of flying insects into an aircraft.

Aircraft↗