Oxido Nitrogenio (NOx)
WHY SHOULD WE CONTROL NOx? NOx represent a family of seven compounds. Actually, EPA regulates only nitrogen dioxide (NO2) as a surrogate for this family of compounds because it is the most prevalent form of NOx in the atmosphere that is generated by anthropogenic (human) activities. NO2 is not only an important air pollutant by itself, but also reacts in the atmosphere to form ozone (O3) and acid rain. It is important to note that the ozone that we want to minimize is tropospheric ozone; that is, ozone in the ambient air that we breathe. We are not talking about stratospheric ozone in the upper atmosphere that we cannot breathe. Stratospheric ozone protects us and the troposphere from ionizing radiation coming from the sun.
Fonte: https://www3.epa.gov/ttncatc1/dir1/fnoxdoc.pdf
