Dr. Andre E. Nel, MD PhD, explained how air particulates injure the airways and promote allergic sensitization. Small particles create oxidative stress; that is, they generate oxygen radicals that can cause damage and lead to cell death. The smaller the particle, the deeper it penetrates into the lungs – and the more damage it causes. Ultra-fine particles not only damage the airways, but they also worsen the inflammation associated with allergies and asthma, and they can damage the cardiovascular system. (You can actually chart an increase in the number of emergency room visits following an increase in air pollution.) Most of these dangerous ultra-fine particles come from the combustion of fossil fuels.
Dr. Grace K. LeMasters, PhD, presented evidence which showed that children who live near high-diesel-traffic areas experience increases in wheezing. She also pointed out that simply taking a two-hour walk on a street with heavy diesel-powered traffic can decrease lung function. Inner-city stop-and-go traffic is more dangerous than fast-moving highway traffic, as stop-and-go traffic pumps out more exhaust particles. Dr. LeMasters also suggested that some children are more vulnerable genetically to damage from air pollutants.
If you live near a highway or other source of air pollution, we recommend an air purifier with an activated carbon filter to adsorb the chemical pollutants. If you must spend time outdoors in a highly polluted area, wear a mask with an activated carbon filter; I recommend the Respro Aero Mask or the Honeycomb Mask.