A new report from the Center for Public Integrity and The Center for Investigative Reporting found that about one in 11 public schools are too close to high-traffic roads or highways.
The problem exposes nearly 4.4 million school children to highly polluted air. And that air can cause asthma attacks, hamper lung development, increase the risk of cancer and even impede cognitive development.
Unlike the smog of Beijing and Paris, the air pollution studied in the report is typically invisible. In fact, a lot of the at-risk schools are in rural towns or smaller cities.
And the investigation found almost a fifth of U.S. schools that opened in the 2014-2015 school year were built near high-traffic roads — even though the Environmental Protection Agency warned school districts about air pollution in 2011.