The above graphic illustrates how the highest concentrations of carbon monoxide and ultra-fine particles occur at the center of roads. As the graphic shows, the further you move from the road, the lower your exposure is to these particles. Dr. Yifang Zhu, an Assistant Professor at Texas A&M University-Kingsville, has shown that in Los Angeles concentrations of carbon monoxide and ultra-fine particles dropped by 60-80% within 100 meters of the road (Zhu et al., 2002).

What this means is that health risks associated with air pollution are greatest for people who are on the road, i.e. people riding in cars, buses, trucks, etc. Reducing the amount of toxins emitted by automobiles is, therefore, pivotal to ensuring that people don’t suffer health complications because of their road travels. This can be accomplished by reducing the number of vehicles on the road and promoting cleaner and more efficient vehicles.