To study the threshold intensity for detection of an alternating current (AC) electric field in human subjects at different temperatures and humidities.
The palm and dorsum of the hand were exposed to fields, representing hairless and hairy skin, in order to clarify whether hair movement is critical for field detection.
Experiments were carried out during hot humid weather of July-August and dry cool air of October-November.
|Exposure 1: 50 Hz||
Experiments took place during hot humid weather of July-August and dry cool air of October-November.
|Additional info||vertical electric field|
|Setup||The upper brass electrode was held 20 mm above the lower aluminum electrode by two insulating posts. The electrodes were movable so that the vertical electric field could be applied on any part of the hand. The lower electrode and the human body were grounded. The lower electrode was in contact with the skin. In the experiments during October-November, hand or forearm was placed inside a small acrylic box (50 x 50 x 50 cm³).|
|electric field strength||115 kV/m||unspecified||calibration||-||October-November experiments|
|electric field strength||50 kV/m||minimum||calibration||-||august experiments|
|electric field strength||60 kV/m||-||calibration||-||august experiments|
|electric field strength||65 kV/m||-||calibration||-||august experiments|
|electric field strength||70 kV/m||-||calibration||-||august experiments|
|electric field strength||80 kV/m||maximum||calibration||-||august experiments|
|electric field strength||42.5 kV/m||minimum||calibration||-||july experiments|
|electric field strength||50 kV/m||-||calibration||-||july experiments|
|electric field strength||55 kV/m||maximum||calibration||-||july experiments|
|electric field strength||10 kV/m||minimum||calibration||-||applied in coarse steps to estimate threshold|
|electric field strength||30 kV/m||minimum||calibration||-||applied in coarse steps to estimate threshold|
|electric field strength||50 kV/m||minimum||calibration||-||applied in coarse steps to estimate threshold|
|electric field strength||70 kV/m||minimum||calibration||-||applied in coarse steps to estimate threshold|
|electric field strength||90 kV/m||maximum||calibration||-||applied in coarse steps to estimate threshold|
Threshold values obtained in the summer were 30-65 kV/m for the hairy skin on the dorsum of the hand, while for the hairless skin on the palm the threshold was greater than 115 kV/m (highest field available due to limitations of the power supply).
During the fall, the threshold was much higher than during the summer (humidity was the main factor for this difference).