Jan. 23, 2001 -- That haze hanging over your city isn't just depressing and foul. The pollution may also be affecting your child's health -- and schoolwork.
According to researchers from California and North Carolina, an increase in air pollution resulted in an almost 83% jump in school absences related to respiratory illness. The results, published this month in the journal Epidemiology, is the first large study to measure increases in missed school days in relation to a rise in air pollution.
"Because the effects of air pollution on school absences are likely to be due to increases in respiratory illnesses, respiratory illness-related absenteeism can be an important and relatively specific integrative outcome for the assessment of the effects of air pollution on children," writes study author Frank Gilliland, MD, of the University of Southern California Keck School of Medicine.
Air pollutants include ozone, noxious gases such as nitrogen dioxide, and microscopic pieces of soot called particulates. Ozone, long known to adversely affect health, is formed when the sun cooks nitrous oxide escaping from vehicle exhaust pipes and factory smokestacks. It can damage breathing by infiltrating the soft tissue that lines the lungs and noses, and it can also harm eyes.
In the study, scientists measured ozone and particulates along with nitrogen dioxide levels every hour in the 12 southern California communities where they conducted the study. They then compared these levels to the reported school absences from respiratory illnesses in more than 2,000 fourth graders.
Besides the increase in school absences from generalized respiratory illnesses, the researchers found an astounding 173% increase in students staying home because of lower respiratory illness characterized by a wet cough. The rise in absences for those with a lower respiratory illness with wet cough, asthma, or wheeze increased by more than two-thirds.
This is not completely out of the blue, though. According to government health officials, five million American children have asthma and they miss 10 million schools days annually. Experts call the incidence of asthma in this country an epidemic, and death from asthma and other respiratory ailments is on the rise.
Children are especially susceptible to the lung-burning gases and tiny particles that lodge in the airways. "The younger the child, the greater the risk they have because their immune systems and organs are not developed," says Reynold Panettieri Jr., MD, chief of the asthma section of the pulmonary, allergy, and critical care division at the University of Pennsylvania Medical Center in Philadelphia.
Though Panettieri tells WebMD that pollution levels in many areas of the country have been reduced in the past 20 years, the rates of respiratory illness and asthma continue to climb. And he says scientists have yet to explain why the breathing difficulties haven't declined also.
Even though overall pollution is less, that doesn't matter on hot, muggy days when any existing pollution is at its worst. "Pretty profound epidemiological evidence exists that as the air quality declines, emergency room visits for respiratory illnesses increase," Panettieri says.
Mark Mallard, MD, medical director of Baylor University Medical Center's Asthma and Pulmonary Rehabilitation Center in Dallas, says that children in lower income urban areas suffer the most from respiratory ailments, especially asthma. There are a number of reasons for this, he tells WebMD, but certainly a major factor is their exposure to air pollution. In addition, these children are often in contact with more dust mites, molds, and roach droppings in their homes, and that contributes to breathing ailments.
"There's no place to hide," Mallard says of the risk of breathing distress, because in urban areas the hot summer temperatures make pollution risks even more acute than elsewhere. "Some of my patients parody the song 'Summertime, and the breathing is harder, fish are jumping, and the ozone is high.'"
Saira Rahim, RRT, coordinator of education and advocacy for Children's Medical Center of Dallas' Respiratory Care Services, echoes Mallard's concern for inner city children.
"The biggest [asthma] population is inner-city kids who are exposed to more pollutants," she says. "The best thing is to keep the child in and away from exposure."
But keeping a kid indoors is not always easy or practical. Mallard and his colleagues researched another option. They conducted a study in eight Dallas schools in which school personnel administered an inhaled steroid to asthmatic youngsters twice a day. This relieved the inflammation and tightening of muscles that narrowed their airways that causes the disease's characteristic coughing and wheezing.
They found that the attendance rate for those treated morning and afternoon with the drug rose to 92%, compared with 78% for children with asthma who were not treated. Not only did this allow the children to stay in school; it also allowed them to participate in activities that may previously have been impossible.