Influence of Negative Air Ions on Drivers

Influence of Negative Air Ions on DriversToyota negatif iyonların sürücülere etkisi.

Kiyomi Sakakibara, Research-Domain 17

2002 Toyota Central R&D Labs., Inc.

Negative air ions are observed at a high oncentration level in places such as near a waterfall and in a forest. Some studies have demonstrated that negative air ions have positive effects on human

performance and mood1, 2). The purpose of the present study was to investigate the influence of

negative air ions on a driver’s mental stress and fatigue. Two kinds of driving-task loading, produced by a imple driving simulator (Fig. 1), have been onducted for this purpose. Sensory evaluation of



mental strain and fatigue, adrenaline in the urine and driving performance were observed. Adrenaline in the urine is a biochemical index of fatigue. Driving ask 1 was the task that required continuous mental train. Subjects were required to drive as exactly as possible on a circular course at a steady high speed of 120 km/hr for 50 minutes. Six male subjects participated in the experiment of driving-task 1. In driving-task 2, subjects were required to perform two tasks. The primary task was to drive at a steady speed of 40 km/hr for 60 minutes. For the secondary ask three light emission diodes (LED) were located on the left side, right side and upper center of the CRT display. Two hand-witches were placed on the left side and on the right side of the steering wheel. A foot-switch was put in the position of the accelerator pedal. The secondary task was to push the corresponding switch as fast as possible when one of the three LEDs was turned on. Fourteen male subjects participated in the experiment of driving-task 2.Both for driving-task 1 and driving-task 2, every subject underwent two repetitions of the experiment,and the data observed in the negative air ion environment, 10,000 ions/cm3, were compared with that observed in a natural air environment (control).

As a result of driving-task 1, there was no difference between the negative ion condition and the

control condition in sensory evaluation. However, the adrenaline level after driving was lower under the negative ion condition than that under the control condition (Fig. 2). In driving-task 2, there was also no difference in sensory evaluation. 

The adrenaline level after driving was also lower under the negative ion condition. In addition, misses in detecting the lighted LEDs during 10 minutes from the beginning was decreased for 57 % of the subjects under the negative ion condition (Fig. 3). These results show that negative air ions can improve fatigue and cognition of the drivers.

References
1) Hawkins, L. H. and Barker, T. : “Air ions and Human
Performance”, Ergonomics, 21-4(1978), 273-278
2) Tom, G., Poole, M. F., Galla, J. and Berrier, J. : “The
Influence of Negative air Ions on Human Performance
and Mood”, Human Factors, 23-5(1981), 633-636
(Report received on Dec. 19, 2001)


R&D Review of Toyota CRDL Vol. 37 No. 1 (2002. 3)
Copyright (C) 2002 Toyota Central R&D Labs., Inc.
2.5m 32"CRT display
Electro-hydraulic vibrator
Computer for a
driving game