HEALTH EFFECTS OF OZONE, CONT'D...

The earlier study of 1,150 children followed for three years suggests that long-term ambient ozone exposure might negatively affect human lung function growth. The researchers observed small but consistent decrements in lung function in the children that were associated with ambient ozone exposure.6 In another new study, Austrian researchers have followed almost 1,000 schoolchildren from eight communities for three years, with lung function measurements taken in the winter and summer. Although they looked at the impact of particulate matter and NOx, they found that exposure to ozone also reduced lungfunction growth, confirming earlier work. The authors note that early impairment of lung-function growth could lead to lower lung function in adulthood, predisposing individuals to chronic pulmonary diseases.7 Researchers have found that when air pollution worsens, more children stay home sick from school due to respiratory illnesses. The University of Southern California researchers found that school absences due to sore throats, coughs, asthma attacks and similar problems increase in the three to five days after a significant rise in ozone.8 Another study of schoolchildren in Nevada also found that increases in ozone levels were associated with an increase in the school absentee rate.9 Children with asthma are particularly susceptible to ozone. One recent indicator that the 1997 ozone standards aren’t protective enough for children with asthma comes from a study of 850 children with asthma ages 4-9 living in eight inner-city urban areas in the United States: the Bronx and East Harlem in New York, Baltimore, Washington, D.C., Detroit, Cleveland, Chicago and St. Louis. Of all the pollutants studied, ozone had the greatest effect on morning peak expiratory flow rate, an indicator of lung function. Adverse respiratory effects were reported in all the cities studied. The authors noted that the results show further evidence of harm to children with asthma at levels below the current 1997 air quality standards.

During this period, researchers found significant reductions in the numbers of urgent care visits, emergency care visits, and hospitalizations for asthma among children ages 1-16.13 A recent study of children has found a possible link between playing team sports in a high-ozone area and an increase in the risk of developing asthma. Researchers at the University of Southern California in Los Angeles followed more than 3,500 children from 12 communities in southern California. None of the children had been diagnosed with asthma when they enrolled in the study, although some had a history of wheezing. After five years, 265 children had been diagnosed with asthma. Overall, children living in communities with high ozone levels who played team sports were more likely to develop asthma. The risk of asthma increased with each additional sport played by a child in a high-ozone community.14

Children with asthma are particularly susceptible to ozone. One recent indicator that the 1997 ozone standards aren’t protective enough for children with asthma comes from a study of 850 children with asthma ages 4-9 living in eight inner-city urban areas in the United States: the Bronx and East Harlem in New York, Baltimore, Washington, D.C., Detroit, Cleveland, Chicago and St. Louis.

For most people, breathing ability is reduced over time. So even the healthy elderly are at increased risk from exposure to ozone and other air pollutants, which further reduces their lung function. Ozone air pollution also increases susceptibility to influenza, pneumonia and other infections, which are especially dangerous for the elderly. A study of the relationship between daily death rates in the elderly, outdoor air temperatures and ozone levels in Belgium confirms the deadly potential of ozone for senior citizens. The study found an association among daily mortality in the elderly and ambient ozone concentration during t he hot summer of 1994.15 In addition, ozone can significantly worsen the condition of people with chronic bronchitis and emphysema, and since most of these diseases occur in the elderly population, these elderly are at special risk for exposure to ozone.