Less scientifically, they found that babies didn't cry as often and as loudly when they were breathing negative ions as they did in normal air. And there is nothing subjective about a bawling baby. Really humid days are murder for anyone suffering from asthma or any respiratory allergy, and the fact that such people find it difficult to breath in hot, humid air may have less to do with the amount of oxygen in the air then with the massive negative ion depletion. Air electricity is quickly conducted to the ground by the moisture in the air, and what negative ions there are attach themselves to particles of moisture and dust and lose their charge. The ion count is always low in cities where there's precious little open ground to generate them.
Pollution makes a bad situation worse, since it tends to deplete the negative ion count even more.
The high pollen count in certain parts of North America each fall cuts even further into the negative ion count, since pollen has the same effect as dust. The end result is that the total ion count in cities is always down to what many scientists consider perilously low levels. As if that weren't bad enough, the normal 5 - 4 ratio of positive ions to negative ions is distorted so that people are, in a sense, victims of positive ion poisoning. Central Air Conditioning and Heating Hot or cool air forced through the duct work of most central heating and air- conditioning systems sets up friction that results in the loss of almost all the negative ions and also draws most of the positive ions out of the air as well. What finally comes out of most heating or air- conditioning outlets in the offices we work in and the rooms we live in is likely to be an overload of positive ions which will upset the mental and physical equilibrium of everyone, not only those of us who are ion sensitive.