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The Effects of Negative Ionisation on Subjective Symptom Intensity and Driver Vigilance in a Moving Vehicle
Author(s) -
Wyon David P.,
Wyon Inger,
Norin Fredrik
Publication year - 1995
Publication title -
indoor air
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.387
H-Index - 99
eISSN - 1600-0668
pISSN - 0905-6947
DOI - 10.1111/j.1600-0668.1995.t01-1-00004.x
Subject(s) - vigilance (psychology) , audiology , poison control , medicine , ionization , psychology , medical emergency , ion , chemistry , neuroscience , organic chemistry
100 drivers aged 23‐65, 53 male and 47 female, were recruited to drive an apparently unmodified passenger car for one hour in city traffic. They were randomly assigned either to a control condition, or to ionised air containing 20 000‐30 000 negative ions/ml, but were unaware of the presence of an ioniser in the vehicle. A computer initiated unprepared signals to which drivers should normally be alert. Drivers responded by pressing a foot‐switch and reporting verbally. Signals were selected at random from 21 possible signals, and were presented for up to 3 minutes, with a random delay of 30‐180 seconds after each response or failure to respond. Subjects reported subjective symptom intensity by marking a set of 11 visual‐analogue scales. Eye symptoms were alleviated by ionisation for subjects aged < 40 years (P<0.05), but older female subjects experienced more eye discomfort, headache and fatigue in the ionisation condition (P < 0.05). Detection of 10 of the 21 signals was better (P < 0.05, 2‐tail) in the ionisation condition. The effect was more often significant in the second half‐hour, for subjects < 40 years, and for women. A significant negative effect (P < 0.05) was observed for the signal indicating speed below true speed.