Air pollution should not be confused with global warming which is caused by CO2. According to the new norms introduced by the World Health Organization, many developed countries do not have a single region with clean air. Many other countries are also moving in this direction of decreasing air quality.
The air you breathe is not local. For example here in the Netherlands, 32% of all air pollution comes from abroad. If you would take out all farmers, industry and traffic some natural areas are still above the norm for healthy nature.
You can take measures locally, but it will not be enough.
The NOx problem
Nitrogen oxides (NOx) are a major contributor in the global issue of air pollution. These gasses contain compounds of nitrogen and oxygen, causing a variety of specific problems.
Destruction of habitat
Acid rain, smog and overfertilisation causes destruction of habitats where millions of species are threatened.
Indoor and outdoor pollution causes problems to the respiratory system and can be measured in years of reduction in lifespan.
While concentrations of the N2O gas are low, it is 300x more potent per molecule than CO2. Resulting in a 6% contribution to global warming.
NOx in the Netherlands
Buying out farms
Reduction of speedlimit