Ozone is ground-level air pollution, sometimes called "smog" in common usage. It's the orange haze that you sometimes see in big cities on hot days. Ozone is formed by a reaction of volatile organic compounds (VOCs), nitrogen oxides (NOx) and sunlight. The USEPA sets the maximum concentration of ozone that can be in the ambient air. This is the "ozone standard", which is currently set at 75 parts per billion.
In order to meet this goal, states develop plans (approved by EPA) to reduce emissions of the two types of air pollutants that contribute to ozone formation: VOCs and NOx. Thus, whenever EPA reduces the ozone standard, it forces the states to find additional reductions of VOC and NOx emissions.
There are many different types of air pollution control equipment on the market today that aid manufacturing and production facilities to meet government mandated emission levels including; catalytic oxidizers, regenerative thermal oxidizers (RTOs), and thermal (recuperative) oxidizers. Check out the “EPA Clamping Down on Ozone Standards” whitepaper that describes this topic in detail.