Air ion effects on human performance 

A review of  literature commissioned by Ecstatic Ltd. 51 Royden Court, Mayfield Rd, Walton on Thames, Surrey KT12 5HZ. Tel: 07000 710 810. Fax: 07000 710811

Introduction

The effect of air ions on the human organism has been the subject of much debate. Commercial units are available which claim beneficial effects through the generation of negative air ions into the atmosphere. Conversely, it has been claimed that an excess of positive ions can cause discomfort and symptoms such as headaches and nausea in some people. Natural air ions may be produced by natural radioactivity and cosmic rays, waterfalls, or wind action. Natural ion balances could be altered in by man made environments such as in buildings or within vehicles, especially with the modern use of polymer materials which are prone to electrostatic charging to high voltages.

Reported evidence concerning the effects of air ions on human performance and health

The possibility that air ions may affect human health has been suggested since the beginning of the 20^th century. In the 1930's Yaglou et al published a series of papers demonstrating physiological effects of air ions and showing that air ion concentrations varied with diurnal and seasonal patterns. Yaglou suggested that air ion control should be considered an important part of indoor air conditioning. Studies in the 1950's and 1960's indicated that human health, performance and mood were affected by certain weather conditions. In particular warm dry winds such as the Sirrocco (Italy), Sharkije (Egypt), Santa Ana (California), Hamsin or Sharav (Middle East) or the Foehn ((Central Europe), are associated with a sudden increase in morbidity (health problems). During these winds about 30% of the population were reported to suffer from migraine, depression, moodiness, lethargy or respiratory symptoms. Behaviour changes were reported to result in an increase in accidents and psychological illness. A further 30% suffered less, and about 40% suffered no effects. According to Sulman (Israel) and Kreuger (California) there was some evidence that these health changes were due to atmospheric electrical changes, in particular air ion concentrations, and the ion polarity ratio (the balance between positive to negative air ion concentrations).

Sulman and Kreuger's work led to a hypothesis that serotonin was involved in a mechanism of interaction between ions and biological systems. Although the concentration of air ions is very low (in fair weather, circa 1000 ions/cc for negative, and 1200 ions/cc for positive ions), Hawkins (1985) asserts that "the evidence that ions do have biological effects is overwhelming." The main action seems to be through entry through the respiratory system.Kreuger (1976) reports research by Winsor and Beckett on human adults and children in which high concentrations of positive ions produced congestion in the nose and pharynx, and when prolonged affected the bronchi.

Various authors have reported significant effects of air ionisation on psychological task performance, but others have not been able to demonstrate such effects. The effects, where reported, are generally consistent; increased negative air ion levels are reported to have beneficial effect on performance whereas depleted ion levels of both polarities, or increased positive ion levels, are reported to result in no change, or a reduction in performance. Hawkins reports that his own studies confirm a significant beneficial effect of negative ions, positive ions having no effect. He reports that negative ions result in greater improvement for complex tasks than for simple tasks. Buckalew and Rizzuto (1982) found that male subjects exposed to negative ions from commercial ion generators for a period of at least 6 hours reported feeling more relaxed and less tired. Reductions in irritability, depression, and tenseness, with increased calmness and stimulation were associated with negative ion exposure. Buckalew and Rizzuto (1984) found no significant effect on performance and physiological condition of 24 male subjects after up to 6 hours exposure to commercial negative ion generators. No alteration in basic cognitive functioning, perceptual-motor performance, reaction time, or grip magnitude, pulse, temperature and blood pressure were found. They state that; "There does remain the possibility of a physiologic, psychologic or performance response to higher concentrations of negative ions, and the need for investigation using a treatment-by-levels approach remains.

Another direction, given evidence of psychological effects of negative ion exposure, is investigating interactions of psychological state and performance effects."Fornof & Gilbert (1988) reported that indoor air ion levels affect the reactions of children to stressors. Negative air ionisation increased physiological tolerance of stressors and reduced secondary effects of stress in behaviour and performance. Improvement in conceptualisation and attention span coincided with the indicators of reduced stress. They concluded that their observations could not be attributed to noxious and toxic chemicals commonly produced with corona air ion formation. Their results confirmed that people of different sympathetic nervous system reactivity respond differently to air ion levels. Autonomic nervous system stability was apparently improved. In a 1984 review Kellogg reports work by various authors on the clinical use of air ions, especially in the treatment of burns and asthma. For example, Kornblueh et al (1958) found that negative air ions, but not positive air ions, afforded relief from hay fever. Kornblueh (1968) has found that burn victims reported cessation of pain and early formation of eschars after exposure to negative air ions. These effects were confirmed by others.

Inbar et al (1982) have reported that negative air ions improved cardiovascular and thermoregulatory system function in men performing a bicycle exercise trial in a hot (40^oC) environment. Heart rate, body temperature and perceived exertion were all reduced.

Serotonin hypothesis

Kreuger (1976) reported that in laboratory animals serotonin, an powerful neurohormone, could be affected by the polarity and concentration of air ions breathed. Serotonin can produce neurovascular, endocrinal, and metabolic effects throughout the body (Kreuger 1976) and plays an important role in mood and sleep patterns. Negative ions act to reduce serotonin levels in the respiratory system, blood and brain, whilst positive ions increased serotonin levels. Hawkins (1985) reports that his own work confirmed these effects. High concentrations of serotonin have been associated with migraine headache attacks. Thus an increase in negative ions would be expected to reduce migraine attacks. Reduced serotonin levels result in a mentally relaxed state and reduction in feelings of depression. Sulman et al have reported that individuals suffering Sharav wind sensitivity have been successfully treated by inhalation of air containing excess negative ions, or by administration of serotonin blocking drugs (Kreuger 1976).The situation is confused, however, by other factors. Negative ions appear to reduce serotonin via enhancement of monoamine oxidase activity. Paradoxically, mental illness is often successfully treated using drugs which inhibit this activity and cause a rise in serotonin levels in the brain.

Factors which may influence the reported experimental results

The research into the effects of air ions has yielded rather variable results. According to Kreugar (1976), sometimes faulty experimental design has allowed the influence of factors other than air ions, and results have been wrongly attributed to ion action. In other cases, no ions reached the subject, and so false results of no ion action were reported. Kreuger reports the major factors causing errors of observation to be;

• neglect of the effect of ozone and nitrogen oxides produced by corona discharge ion sourcesfailure to adequately monitor and control ion densities, temperature and humidityuse of air containing particulate or gaseous pollutants. These combine with air ions to cause fluctuating ion densities

• failure to hold experimental subjects at electrical ground potential. A non-zero body voltage can cause repulsion of ions and reduced ion ingestion.

Buckalew and Rizzuto 1984) cite non-standardised ion generating equipment, different exposure lengths and ion concentrations, non-comparable measures and differential monitoring of ion levels as detracting from the comparability of studies. Kellogg (1984) stated that air ion source, air quality, associated field, ambient ion levels, absorbed ion dose, grounding of the target subject, species, strain or individual subject population, and the protocol used to avoid placebo effects should be specified in a study of air ion effects.

Ion effects on other organisms

It has been argued that air ions could not affect biological systems due to the low concentrations in which they are present in the atmosphere. Kreuger (1976) refutes this argument, citing other examples where extreme sensitivity to agents is know, such as pheromone response, the response to the eye to low level light, and studies of the reported role of electric and magnetic fields in orientation of cockchafers and shape and mobility of amoebae. Kreuger exposed mice to influenza virus and observed the rate of death for animals living in normal and ion treated environments. Increased death rates were observed for ion depleted, and positive ion enhanced environments. Death rate decreased for high unipolar concentrations of negative ions. Similar results were found in experiments with exposure to a fungal pathogen and a second bacterial type. The life span of mice in an ion-depleted atmosphere has been reported to be shortened. Kreuger pointed out that a known effect of atmospheric pollutants is to deplete small ion concentrations. Beckett has measured ion densities in San Francisco and found that as pollution developed over the working day, small ion count reduced to 80 ions per cc, less than 10% of the expected concentration in a residential district. Ion lifetime measured over the sea also was reduced by airborne pollutants drifting from the land.Kreuger reviewed research on the effects of ion concentrations on microorganisms. Negative and positive ion concentrations of 5x10⁴-5x10⁵ per cc have been demonstrated to slow growth in a variety of bacterial cultures. Negative ions were more effective in this. These levels of ion densities were shown to reduce viable cell count in bacterial aerosols in enclosed environments. Similar results were obtained independently by Russian and American workers. Ions of either charge have also been reported to inhibit spore germination and kill certain types of microorganism.Kreuger also reported that ion depletion has been found to affect plant growth. Growth, measured by elongation and fresh and dry weights was reduced. Leaves were soft and lacked normal turgor.

Discussion of issues relevant to the motor vehicle environment

The air ion balance and levels which may be experienced by personnel in a motor vehicle are not currently reported. This information is essential for assessment of the possible air ion responses of occupants of a vehicle.A second factor which may be extremely important is the subject's body voltage. A high body voltage could considerably alter the ingestion rates of ions. Ions of like polarity would be repelled from the body, and an effective depletion of ingested ions of this type can be expected. Similarly, ions of the opposite polarity would be attracted, and enhancement of ingestion of opposite polarity ions can be expected. Thus it is possible that the same effect as positive ion enhancement could be produced by a high negative body potential, even if the ambient air ion concentrations are balanced. Control and reduction of body voltage to a near zero condition can be expected to reduce any such effects and restore ion ingestion to that due to the ambient air ion balance condition.

Conclusions

The consensus of the literature reviewed is that environmental air ion concentration levels and balance can affect a wide range of biological organisms, including humans. Elevated negative air ion levels are widely reported to have beneficial effects on humans including enhanced feeling of relaxation, and reduced tiredness, stress levels, irritability, depression, and tenseness.Depleted ion levels and enhanced positive ion levels are reported to have no effect, or deleterious effects. The body voltage of the subject is likely to play an important role in affecting the ingestion of ions. In an environment of balanced air ion levels, the balance of ingested ions may be heavily influenced by a high body voltage. High positive body voltage would be expected to reduce positive ion ingestion and increase negative ion ingestion. High negative body voltage would be expected to reduce negative ion ingestion and increase positive ion ingestion. These effects are expected to be ameliorated by maintaining the body potential near zero.

References

Buckalew L W, Rizzuto A. Subjective Response to negative air ion exposure. Aviation, space, and environmental medicine. 53, (8) 822-3, Aug 1982

Buckalew L W, Rizzuto A. Negative air ion effects on human performance and physiological condition. Aviation, space, and environmental medicine. 55, Part 8, 731-734, Aug 1984

Fornof K T, Gilbert G O. Stress and physiological, behavioral and performance patterns of children under varied air ion levels. Int. J. Biometeorol. 32, 260-270, 1988

Hawkins LH. Biological significance of air ions. Proc. IEE Colloquium on ions in the atmosphere, natural and man made. London, UK, 1985. BLL Conf Ind. 3315.470 No 88 1985.

Inbar O, Rotstein A, Dlin R, Dotan R, Sulman F G. The effect of negative air ions on various physiological functions during work in a hot environment. Int. J Biometeor. 26 (2), 153-163, 1982

Kreuger A P, Reed E J. Biological impact of small air ions. Science, 193, 1209-13. 1976.

Kellogg E W. Air ions: Their possible biological significance and effects. J Bioelectricity 3 (1&2), 119-136, 1984

Kornblueh I H, Piersol G M, Speicher F P. Relief from pollinosis in negatively ionised rooms. Am. J. Phys. Med. 37, 18-27, 1958

Kornblueh I H. Aeroionotherapy of burns. in Bioclimatology, Biometeorology and Aeroionotherapy.

Gualtierotti et. al. eds., Carlo Erba Foundation, Milan 1968.Sulman F G. The effect of air ionisation, electric fields, atmospheric and other electric phenomena on man and animal. Charles C Thomas, Springfield, Ill. 1980.

Yaglou C P, Brandt A D, Benjamin L K C. Physiological changes during exposure to ionised air. Heating, Piping, Air conditioning, 5, 423, 1933

Yaglou C P, Benjamin L K C. Diurnal and seasonal variations in small ion content in outdoor and indoor air. Heating, Piping, Air conditioning, 6, 25, 193