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Recent research has claimed that an excess of positive ions in the air can have an ill effect on people's
physical or psychological health. What are positive ions? Well, the air is full of ions, electrically charged
particles, and generally there is a rough balance between the positive and the negative charged. But
sometimes this balance becomes disturbed and a larger proportion of positive ions are found. This
happens naturally before thunderstorm, earthquakes when winds are blowing in certain countries. Or it
can be caused by a build-up of static electricity indoors from carpets or clothing, or from TV sets,
duplicators or computer display screens.
When a large number of positive ions are present in the air many people experience unpleasant effects
such as headaches, fatigue ,excessive anger, and some particularly sensitive people feel sick or even
suffer mental disturbance. Animals are also affected, particularly before earthquakes, snakes have been
observed to come out, rats to flee from their burrows, dogs howl and cats jump about unaccountably.
This has led the US Geographical Survey to fund a network of volunteers to watch animals in an effort to
foreseesuch disasters before they hit vulnerable areas such as California.
Conversely, when large numbers of negative ions are present, then people have a feeling of well-being. Natural conditions that produce these large amounts are near the sea, close to waterfalls or fountains, or
in any place where water is sprayed, or forms a spray. This probably accounts for the beneficial effect of
a holiday by the sea, or in the mountains with streams or waterfalls.
To increase the supply of negative ions indoors, some scientists recommend the use of ionisers. They
claim that ionisers not only clean and refresh the air but also improve the health of people sensitive to
excess positive ions. Of course, there are the detractors, other scientists, who dismiss such claims and
are skeptical about negative/positive ion research. Therefore people can only make up their own minds
by observing the effects on themselves, or on others, of a negative rich or poor environment. After all it is
debatable whether depending on seismic readings to anticipate earthquakes is more effective than watching the cat.
1. What is an ion according to the passage?
A. It's a charged particle.
B. It's basically static electricity indoors.
C. It's a balance between the positive and negative charged.
D. It's an ill effect on people's physical and psychological health.
2. What effect does exceeding positive ionization have on most of the people?
A. They will throw up.
B. They will be sick and tired of life.
C. They may feel rather bad-tempered.
D. They may feel they are out of their mind.
3. A high negative ion count is likely to be found           .
A. in a mountainous area.
B. by a water spray in a garden.
C. close to a slow-flowing river.
D. near a pound with a water pump.
4. What is the author's attitude towards the use of ionisers?
A. Neutral.
B. Opposed.
C. Supportive.
D. Ambiguous.

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