In performing the ozone lab I became interested in the processes by which ozone is created by electrical equipment such as a high powered blender or copy machine. Dr. Dehaan explained that the electric arc within such machines supplies the energy needed for ozone to be produced from ambient O2 molecules. 3-O2 --Electric Energy--> 2-O3. Electronic motors that are driven by an electric arc are common in many household devices such as brush vacuums and kitchen appliances. Other less common items that produce significant electric arcs are tasers and photocopiers. Though these devices are known to produce ozone, preliminary tests of a high-powered blender were lower than those recorded outside (note: the time of the blender test was shorter by 25 minutes). Some lamps which utilize a gas in a pressurized tube contain open electrical arcs that can, over time, produce dangerous amounts of ozone. In researching this subject, I came upon a patent for a device that attaches to such lamps that converts toxic ozone into oxygen. The fact that such a device exists is a testament to the ability of such electrical arcs to produce ozone in large amounts.

http://www.patentstorm.us/patents/3949258/description.html

In nature, electrical arcs millions of times more powerful than those found in electric appliances can be found in the form of lightning. Lake Maracaibo in Venezuela is a location which has higher incidences of lightning than almost any other location on earth. These frequent lightning storms occurring many times per day produce huge amounts of ozone from oxygen in the air and according to some, this phenomenon represents the largest single contribution to ozone in the troposphere.

http://en.wikipedia.org/wiki/Catatumbo_lightning