A new study out of the University of Southern California shows that kids who breathe traffic-related air pollution at school are more likely to develop asthma, even after taking into account levels of air pollution at their homes. The study, published in the journal Environmental Health Perspectives not only adds credence to the growing body of research suggesting a link between asthma and traffic, but it also shows just how large a role schools play in the health of students.

Asthma is one of the most common childhood diseases in the United States. The rates among school-aged kids have been steadily increasing for years. Asthma is a lung disease with symptoms that include wheezing, coughing, shortness of breath and difficulty breathing — symptoms that lead to absences from school and the inability to participate in physical education or other exercise programs.

To determine the link between asthma and traffic-related pollution, researchers followed almost 2,500 asthma-free children from the age of 6 years old, those just entering either kindergarten or first grade. The children were from 45 different schools in 13 communities in Southern California.

Outdoor traffic-related air pollutants were measured continuously at central neighborhood locations near the schools during the three-year study. The child's exposure to traffic-related pollution at home and school were estimated. Researchers gathered family health history, housing, smoking and other personal information from questionnaires given at the start of the study and once a year after that.

During the study, 120 children developed asthma. Researchers found that pollution exposure at school may be higher because of deeper, more frequent breathing during exercise and recess. Also, schools may have higher pollution levels in mornings and evenings when buses and cars congregate to drop off and pick up kids.

This is more compelling evidence for the need to ban bus (and car) idling at schools. Talk to your school administrator about putting a no-idling policy in place at your child's school.

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