Ozone Could Cause Asthma

Children in Southern California who live in areas with high levels of ground-level ozone and play team sports are more likely to develop asthma than other children. Worsening of asthma with high ozone concentrations is documented in previous studies, but researchers claim that this is the strongest evidence yet that ozone can cause asthma.1

The risk of developing asthma for all 3535 children in the study was no greater in six high ozone communities than in six low ozone communities. However, when the researchers compared only children who played team sports, they found that children who played three or more team sports in the high ozone communities were 3.3 times more likely to develop asthma than children who did not play team sports. In the low ozone communities, there was no difference in the development of asthma in children who played three or more team sports or no team sports.

Children who played more active sports such as basketball, football, soccer, swimming and tennis in a high ozone community had an increased risk of developing asthma, whereas children who played low activity sports such as baseball, softball, and volleyball were not at an increased risk.

Dr. Stuart Abramson, Associate Director of the Children's Asthma Program at Texas Children's Hospital said, "This study supports the notion that we should pay attention to the air quality alert system. When ozone levels are high, we should stay indoors as much as possible and avoid vigorous outdoor activities at those times." To find out when ozone levels are high so you can reduce your child(ren)'s exposure to harmful levels, listen for ozone reports on TV and radio, sign up for e-mail notices (www.hcoem.org), or call 1-888-994-9901.

(1) Peters, JM et al. Asthma in exercising children exposed to ozone:
a cohort study. The Lancet 2002, 359: 386-391

Lung Damage in Children

One would not expect apparently healthy children to have lung damage, but a report about children who grew up breathing polluted air in Mexico City says they do. Previous studies indicate higher rates of lung diseases such as asthma in children living in polluted areas. However, researchers from North Carolina say this is the first study to measure lung damage in children who have no symptoms of lung problems.

Researchers examined the x-rays of 241 children in Mexico City and compared them to x-rays of 19 children who lived in a small coastal town. Sixty-three percent of the Mexico City children had excessive inflation of both lungs, and 52% had markings that could indicate inflammation along the airways. Only one child in the small coastal town showed any type of lung damage.

The study took place over 20 months, when ozone smog levels in Mexico City exceeded U.S. air quality standards an average of four hours a day. Although Mexico City has much worse smog than U.S. cities, including Houston, the researchers claim that the results can be generalized to areas with lower pollution levels.

Children's Exposure to Ozone

Researchers measured ozone levels indoors, outdoors, and in the personal breathing zones of 200 children, ages 6-12, in the first estimation of exposure to ozone over a one year period.1 In two Southern California high-ozone communities, children's personal exposures were lower than the outdoor home levels but higher than indoor ozone levels.

Children living in a mountain community had higher ozone exposures than in the other high-ozone community. This difference was attributed to higher outdoor ozone concentrations, more time spent outdoors in the mountains and higher indoor ozone concentrations due to open windows. Age had no effect on exposure, presumably because all these elementary students participated in similar outdoor activities and had a similar school-year schedule.

(1) Spengler JD, et al. The Harvard Southern California chronic ozone exposure study. Environmental Health Perspectives 2000, 108(3):265-270

Smog affects the unborn

For the first time, a UCLA study has linked air pollution with birth defects in Southern California - even during a period when air pollution was declining1. The study compared outdoor air measurements of four pollutants and birth defects records on thousands of babies born from 1987-1993. Pregnant women were three times more likely to deliver babies with defective heart valves and cleft lips and palates if they had been exposed to high levels of ozone or carbon monoxide. These results were only statistically significant in the second month of pregnancy, the time when organs and facial structures develop.

This study is part of a growing body of evidence about the health effects of air pollution on infants and unborn babies. Other studies worldwide demonstrate an association between air pollution and low birth weight, premature births, still-births, and infant deaths, but this is the first to link air pollution with birth defects.

(1) Harris JA, et al. Ambient air pollution and risk of birth defects in Southern California. Am J Epidemiol 2002 Jan 1; 155(1):17-25

Disparities in Children's Environmental Health

Despite advances in cleaning up the environment over the last 30 years, certain children suffer a disproportionately higher degree of harmful exposures, particularly from air pollution. These children tend to live in urban communities, come from families that have low income, and include a high proportion of ethnic minorities. The "environmental justice" or "environmental equity" movement aims to equalize the environmental exposure and related health risk disparities between minorities and low-income populations in urban areas and the general population, including children.

Negative environmental consequences of air pollution in urban areas include mortality (deaths due to heart or lung disease), increased use of healthcare (hospitalization, ER visits, doctor visits), increased respiratory symptoms (asthma exacerbation, infections, allergies), and lung cell changes. These effects can be more severe among children living in low-income, minority communities.

Children from these communities may also have greater exposures to specific pollutants than non-minority children. For example, many of the communities along the Houston Ship Channel have high minority populations that have lower incomes than average for the Houston area. Children living close to petro-chemical industries along the Ship Channel are exposed to higher levels of toxic pollutants than children in far west Houston.

In addition to air pollution from industry, many children from minority and low-income communities are also affected by air pollution from freeway traffic. Interstates 10, 610, and 45, U.S. Highway 59 and State Highway 225 cut through many of the same communities affected by air pollution from the Ship Channel.

Besides increased exposure, other factors may contribute to the severity of air pollution effects among children in minority and low-income communities including socioeconomic stresses, poor nutrition, inadequate health care, and pre-existing disease. In addition, many of these children may not have access to the health care they need for problems caused or aggravated by air pollution.

Source: ALA, Urban air pollution and health inequities.
Env. Health Perspectives 2001; 109(3):357-374

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Children and Air Pollution

An estimated one hundred thousand children have asthma in Harris County1. 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

Children are more sensitive to air pollution than adults because they:
· Are outdoors more
· Are outdoors in the summer
· Are more active
· Breathe more rapidly
· Breathe through mouth
· Have developing lungs.

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Got an air complaint?

Ever worry that what you smell in the outside air might be harming your children's or your health? Four agencies in the area will respond to air complaints depending on where you notice the smell. If it is in the City of Houston, call 713-640-4200. If it is outside the City limits but within Harris County, call 713-920-2831. For complaints in Galveston County call 409-938-2251. Outside Harris and Galveston Counties the number is 713-767-3712. All agencies will provide follow-up information to the complainant.

MfCA has new logo

Thanks to our volunteer graphic designer, Andrea Dunn, Mothers for Clean Air has a logo that conveys the mission of our organization. The new logo features four multi-ethnic, multi-age, persons of either gender standing in front of a cloud representing clean air. Our name curves over the top of the cloud in a contemporary, youthful font. You can see the logo in color on our web site www.mothersforcleanair.org.