Magnetic fields produced by hand held hair dryers, stereo headsets, home sewing machines, and electric clocks

Abstract

A recent epidemiologic study reported associations between leukemia risk in children and their personal use of television (TV) sets, hair dryers, and stereo headsets, and the prenatal use by their mothers of sewing machines. To provide exposure data to aid in the interpretation of these findings, extremely and very low frequency (ELF and VLF) magnetic fields produced by a sample of each type of appliance were characterized in a field study of volunteers conducted in Washington DC and its Maryland suburbs. Questionnaire data regarding children's or mothers' patterns of usage of each type of appliance were also collected. ELF magnetic fields measured 10 cm from the nozzles of hair dryers were elevated over the ambient by a mean factor of 17 when these devices were in use. Fields near headsets being used to listen to music were not distinguishable from ambient levels except at frequencies below and well above 60 Hz and, even then, field levels were < 0.01 microT. Home sewing machines produced ELF magnetic fields that were elevated by a factor of 2.8 over ambient levels at the front surfaces of the lower abdomens of mothers. Estimated mean daily times of usage of hair dryers, stereo headsets, and sewing machines were 2.6, 19, and 17 minutes, respectively. These data and previously published data on TV sets, do not provide a consistent picture of increased (or decreased) leukemia risk in relation to increasing peak or time weighted average (TWA) ELF magnetic field exposure. The data could, however, conceivably be compatible with some more complex biophysical model with unknown properties. Overall, the results of this study provide little evidence supporting the hypothesis that peak or TWA ELF magnetic fields produced by appliances are causally related to the risk of childhood leukemia in children.

Quantification of lifetime accumulated ELF-EMF exposure from household appliances in the context of a retrospective epidemiological case–control study

“…The average time of daily use in the NLL (means ¼ 26 min, s ¼ 44.5, Max ¼ 343 min) was comparable to the study of Kaune et al (2002), though (geometric means ¼ 17 min, s ¼ 43, Max ¼ 180 min). A similar problem arose for categorized answers in hair-dryers.…”

“…This approach requires appropriate weighing of the different appliances with respect to their contribution to lifetime exposure. Consequently, we Typical distances: Hair-dryers: 9.774.8 cm, 33 people in the study of Kaune et al (2002). TVs: Children kept a distance of 230795 cm to watch TV programs (Kaune et al, 2000).…”

“…According to the producers of waterbeds, systems sold in Germany are Kanthal, Swedish System, Canadian System, New Zealand System (until 1990), and the TAS System (since 1995, 0.07 mT) (Thomas Schielke, Vontana Company, July 19, 2001, personal communication). Reference for differentiation between ''old'' and ''new'' models in the quantification concept is the submission date of Delpizzo (1990 Kaune et al, 2002) and in 50 cm: 0.059 mT; s=0.045 (Preece et al 1997;Kaune et al, 2002). For TVs: intermediate categories between 50 cm and 1 m, 1 and 2 m, 2 and 3 m: 50 cm: 0.21 mT, s g =1.24 (Preece et al, 1997;Kaune et al, 2000); 1 m: 0.06 mT; s g =1.25 (Preece et al, 1997;Gauger, 1985; Bundesamt fu¨r Strahlenschutz (BfS) 1998; Kaune et al, 2000); 2 m: 0.011 mT, s g =1.46; 3 m: 0.011 mT, s g =1.46 (Kaune et al, 2000).…”

“…Movements of hand-held dryers can cause high peaks in the even and odd harmonics (i.e. superimpositions of high-frequency fields that represent either even or odd multiples of the basic frequency) (Mader et al, 1992;Lovely et al, 1994;Kaune et al, 2002). Considering the resultant root-mean-square field (rms, or total field), however, even a 25% harmonic content would increase the rms only negligibly (by ca.…”

“…Preece et al, 1997). The latter models, however, produce magnetic flux densities 4-5 times smaller than motorized clocks (Kaune et al, 2002). Electronic models were not included in our analysis.…”