title: Measured radiofrequency exposure during various mobile-phone use scenarios.
abstract: Epidemiologic studies of mobile phone users have relied on self reporting or billing records to assess exposure. Herein, we report quantitative measurements of mobile-phone power output as a function of phone technology, environmental terrain, and handset design. Radiofrequency (RF) output data were collected using software-modified phones that recorded power control settings, coupled with a mobile system that recorded and analyzed RF fields measured in a phantom head placed in a vehicle. Data collected from three distinct routes (urban, suburban, and rural) were summarized as averages of peak levels and overall averages of RF power output, and were analyzed using analysis of variance methods. Technology was the strongest predictor of RF power output. The older analog technology produced the highest RF levels, whereas CDMA had the lowest, with GSM and TDMA showing similar intermediate levels. We observed generally higher RF power output in rural areas. There was good correlation between average power control settings in the software-modified phones and power measurements in the phantoms. Our findings suggest that phone technology, and to a lesser extent, degree of urbanization, are the two stronger influences on RF power output. Software-modified phones should be useful for improving epidemiologic exposure assessment.
authors.affiliation: Exponent Inc., Menlo Park, California 94025, USA. Mkelsh@exponent.com
authors.forename: Michael A
authors.initials: MA
authors.lastname: Kelsh
authors.forename: Mona
authors.initials: M
authors.lastname: Shum
authors.forename: Asher R
authors.initials: AR
authors.lastname: Sheppard
authors.forename: Mark
authors.initials: M
authors.lastname: McNeely
authors.forename: Niels
authors.initials: N
authors.lastname: Kuster
authors.forename: Edmund
authors.initials: E
authors.lastname: Lau
authors.forename: Ryan
authors.initials: R
authors.lastname: Weidling
authors.forename: Tiffani
authors.initials: T
authors.lastname: Fordyce
authors.forename: Sven
authors.initials: S
authors.lastname: Kühn
authors.forename: Christof
authors.initials: C
authors.lastname: Sulser
mesh_terms: D040421:Cell Phone / Q000145:classification / Q000706:statistics & numerical data*; D004781:Environmental Exposure / Q000032:analysis* / Q000706:statistics & numerical data; D006302:Health Services Research / Q000145:classification / Q000379:methods* / Q000706:statistics & numerical data; D006801:Humans; D019047:Phantoms, Imaging; D011846:Radio Waves; D018570:Risk Assessment / Q000379:methods / Q000706:statistics & numerical data; D012424:Rural Population; D013383:Suburban Population; D014505:Urban Population