Photochemical Ozone Formation Potential (Smog) – Summary Measure Details

Under certain climatic conditions, air emissions from industry and transportation can be trapped at ground level where, in the presence of sunlight, they produce photochemical smog, a symptom of photochemical ozone creation potential (POCP).  While ozone is not emitted directly, it is a product of interactions of volatile organic compounds (VOCs) and nitrogen oxides (NOx).  The “smog” indicator is expressed on a mass of equivalent NOx basis.