271 
RECENT PROGRESS IN THE USE OF OZONE IN VENTILATION, 
F. O. ANDEREGG, Purdue University. 
The name ozone is associated with freshness in the air such as is 
experienced after thunderstorms; and in the open country at almost all 
times: Great interest has been taken in the observation of “ozone days” 
in the past and a large amount of data has been accumulated, mostly of little 
value. With these associations the name possesses good advertising value 
and advantage has been taken of this to exploit the use of ozone to an ex- 
tent comparable almost with gold mining or oil well prospects. The great 
number of extravagant claims, which have been made, have tended to bring 
this activated form of oxygen in considerable disrepute with scientists 
and others who like to be careful as to the truth of the statements they 
. accept. The reaction has been so great that a good many pecple have 
come to think that the term ‘ozone’ and all it signifies is merely a snare 
and delusion. Just because bad oil stock has been sold is not a good reason 
for believing that all oil stock is worthless; nor is it right to allow oneself 
to be completely prejudiced by extravagant claims of certain unscrupulous 
persons. Let us first of all, consider the actual facts of the case. 
Ozone does seem to have a stimulating effect if taken at the correct con- 
centration. Thus, right after a thunderstorm, when the air is exhileratingly 
fresh, ozone is present at a concentration of about one part in ten million. 
This is sufficient to act on a sensitive photographic plate. Such a concentra- 
tion is not at all harmful but is actually stimulating. But this stimulation is 
not one with harmful after effects, since it consists in the addition to the 
blood of a more active modification of oxygen which is then used in oxidiz- 
ing the fuel in the body, thus making available more energy for muscular 
work. 
Other stimulants like alcohol have injurious side actions which often 
cause a great deal of harm. But even here the claim is made and supported 
by considerable evidence that alcohol in small concentrations is practically 
harmless and may even be possibly beneficial. The ill effects of highly 
concentrated alcohol are too well known to need more than mere mention. 
In a similar manner ozone of a concentration of more than one part in a 
million becomes harmful. It begins to attack the mucuous membrane with 
very disagreeable results. Headaches are produced which are apt to be 
very disagreeable. It does not take very much ozone to make more than 
one part in a million of air, so that the mistake that has been made by 
most exploiters was to use apparatus of too high a capacity. With the pro- 
duction of too much ozone disagreeable results have followed. 
For office ventilation there are manufactured by many concerns in this 
country and abroad cabinet ozonizers which produce a lot of ozone for a 
very small power consumption. Since a large part of the price of the ap- 
paratus depends upon the size, the tendency has been, partly through greed 
and partly through ignorance to make ozonizers too big. I have known of 
a great many cases where these cabinets have been installed in banks and 
offices where after a while they have had to be discarded because of the 
concentration being much too great. To be successful, the amount of 
