Excuse the delay as we were focusing on the terrific ASMA show in Anchorage. Let's wrap up the discussion on Ozone.
Ozone (O3or trioxygen) is found in low concentrations in the lower atmosphere (ozone layer) where it acts as a protective shield, blocking out harmful UV rays. On the ground, it is a pollutant that can affect the respiratory systems of animals (including humans) and will negatively affect photosynthesis of sensitive plants. It is a key ingredient in smog. It is commonly thought that ozone is produced directly in car exhaust and by industrial plants. In truth, it is an indirect process of the UV rays in sunlight reacting with the air containing hydrocarbons and nitrogen oxides. Ozone is then formed either at the source of emission or up to several miles away (downwind).
Adding to these effects, ozone has been found to have many industrial and consumer applications.
Ozone used in industry is measured in μmol/mol (ppm, parts per million), nmol/mol (ppb, parts per billion), μg/m3, mg/hr (milligrams per hour) or weight percent. Depending on the conditions (especially temperature and humidity) and method of generation, the concentrations can range from 1 - 30%. Uses of ozone range from disinfecting water in pools, cleaning air and laundry in hospital and killing insects in grain to processing of manufacturing and production.
There are a variety of ways ozone is generated, but the two main methods are corona discharge and UV light.
Corona discharge method - This is the most common type of ozone generator for personal uses. These units usually work by means of a corona discharge tube. They typically use ambient air and are fluctuate based on weather conditions, therefore they are more variable in terms of the ozone production. An air dryer is often added to reduce nitrogen oxides by-products and increase ozone production.
Ultraviolet light - UV ozone generators employ a light source that generates a narrow-band ultraviolet light, mimicking the production of ozone in the atmosphere. When used in calibration systems, such as those manufactured by Environics, there are a variety of industry standards that must be met to guarantee accuracy and reliability of the ozone produced. Our ozone generators (see partial P&ID below or full image here) are all factory calibrated using a NIST traceable ozone standard and perform to the EPA criteria for ozone transfer standard.