Clarifying Aqueous Ozone vs. Smog

On very hot summer days in most major US metropolitan areas there are periodic “Smog Alerts” that are at times announced as “Ozone Alerts." Sometimes there are warnings that the very old and the very young should avoid going outdoors if the air quality is very poor. These warnings create angst and confusion among users of ozone for recreational waters such as pools and spas.

While these “Smog/Ozone Alerts” are very real and must be taken seriously, there is virtually no correlation between ozone levels in polluted air and aqueous ozone used as an antimicrobial water sanitizer. “Photochemical smog" (summer smog) is caused by the action of sunlight on a mixture of hydrocarbons and oxides of nitrogen created mostly by automobile and industrial exhaust emissions. This smog contains secondary pollutants such as ozone, aldehydes and fine particles.” (EPA source: Of these “secondary pollutants,” ozone (as an indicator) is singled out as it is easily and accurately monitored, and directly proportional to overall smog levels. Thus “Smog” and “Ozone” alerts have unfortunately become synonymous.

The process of using “manufactured” ozone, which is dissolved in water as an aqueous antimicrobial sanitizer, has absolutely no correlatoin to smog or the ozone layer. Once dissolved in water, ozone will not drift back into the surrounding air at measureable levels. In the United States, ozone has been used since 1982 to sanitize bottled water. Ozone has been used in pools and spas for decades with great success at attaining healthy water quality and reducing the use of traditional halogenated chemicals (chlorine).


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