Children and Air Pollution

An estimated one hundred thousand children have asthma in Harris County (1). These children suffer the most on high ozone days. They may require extra medication, a visit to the emergency room, or even hospitalization when ozone levels are high. The remaining 900,000 apparently healthy children in Harris County can suffer coughing, wheezing, shortness of breath, more respiratory infections and worse allergy symptoms when ozone levels are high.

Why are children affected more?

When it comes to air pollution, children are not little adults. Children are more sensitive than adults to the adverse health effects of air pollution because of their activity patterns and their young, developing bodies.

Children are outside more than adults and also spend more time outside in the summer when ground level ozone concentrations are highest. Nationally, children spend an average of 50 percent more time outdoors than adults. When outside they are more active and when active, they breathe in more air and therefore more pollutants. In addition, when engaged in vigorous activity, children often breathe through their mouth which does not have the cleansing effect of breathing through the nose. Unlike adults, children either do not experience or do not respond to warning signals, like coughing, wheezing, and shortness of breath when their lung function drops. Therefore, children are less likely to stop exercising or move indoors upon exposure, thus further increasing their exposure to air pollution.
Even at rest, children have a higher ventilation rate (breaths per minute) than adults. This causes children to breathe in more air per pound of body weight and per lung surface area than adults. A higher dose of air pollution to the lungs and other organs can result in more air pollution damage.

Because children are smaller than adults, their airways are also narrower. Irritation or inflammation of the airways from air pollution will cause children to have difficulty breathing. The same degree of inflammation in a child's airways will cause much greater problems than in an adult.

Children with asthma whose airways are already inflamed have even smaller air passages than normal children. When their inflamed airways are further challenged by polluted air, their respiratory symptoms can become worse. Children with allergies can also respond similarly when breathing polluted air.

Since children's bodies are still developing, damage caused to the lung tissue by inflammation, infection or scarring can affect further development of the lung. Repeated damage to a child's lungs may result in long term decreases in lung function or permanent scarring that may lead to chronic lung problems later in life.
Air pollution can also cause changes in lung cells that weaken the lung's defense mechanisms. Consequently, children exposed to ozone and other air pollutants may have more respiratory infections and greater respiratory allergic symptoms.

What can be done

The American Academy of Pediatrics recognizes the specific vulnerability of children to air pollution and in 1993 made recommendations to government agencies and pediatricians (http://www.aap.org/policy/04408.html). Although written nearly a decade ago, they still have relevance today. Among others, the Academy recommends that government agencies "must act more vigorously in the arena of pollution prevention" and "should act aggressively to implement the requirements of the Clean Air Act." For pediatricians the Academy recommends that "pediatricians should become informed about air pollution problems in the community" and that pediatricians express "their concern about the child health hazards of air pollution to their representatives and to policymakers." Unfortunately, this advice is still good for the twenty-first century.

(1) Growing Up in Houston, Children at Risk 2000. Source: American Lung Association. Danger Zones: Air pollution and our children. NewYork, 1995.