Exposure tocosmic radiation ofBritish Airways flying crewonultralonghaul routes

British Airwayshascarried outradiation monitoring inConcorde formorethan20 yearsand hasuseda heuristic model basedon dataquotedby theNational Aeronautics and SpaceAdministration (NASA)tomodelradiation exposurein alllonghaul fleets. Fromthesedataithas beencalculated thatnoflight deckcrew wouldexceedthecontrol level of6mSvly currently underconsideration byregulatoryauthorities, whichisthreetenths of theoccupational doselimitof20mSv/y recommended by the International Commissionon Radiological Protection (ICRP).The modelsuggested thatless than4%ofcabincrewbasedinTokyoflyingonlybetween LondonandJapancould reachorexceedthe6mSv/ylevel, based on a predicted effective doserateof7 uSv/h. Tovalidate thiscalculation asampling measurementprogrammewascarriedouton nineroundtrips flownbya Boeing747-400betweenLondonand Tokyo.Theradiation field wasmeasured withdosimeters usedforroutine personal monitoring (thermoluminescence dosimeters (TLDs)and polyallyldiglyco l carbonate neutrondosimeters). Thelimitations ofthemethodology areacknowledged,buttheresults indicate thatthe effective doseratewas 6pSv/hwhichis consistent withthepredicted effective doserateof7,uSv/h. Thisresult, whichis inaccordance withotherreported studies indicates thatitisunlikely thatanyofthe cabincrewbasedinTokyoexceeded the6 mSv/ylevel. Inaccordance with"aslow as reasonably achievable" principles British Airwayswillcontinue tomonitor flying crewroutesandhoursflownto ensurecompliance. (Occup Environ Med1996;53:495-498)