Atmospheric contamination is one of society's main concerns, with nitrogen dioxide (NO2) and tropospheric ozone (O3) being among the contaminants that are giving rise to the most concern. In principle, the measures to reduce NO2 contamination effectively are fairly easy to identify; however, reducing O3 contamination is much more complex because it is a secondary contaminant that is not emitted directly but is generated on the basis of chemical reactions in the atmosphere.
* This article was originally published here