The American Public Health Association (APHA) this week petitioned the U.S. Environmental Protection Agency (EPA) to adopt stronger, more protective standards to safeguard the health of the public from ground-level ozone, according to an APHA press release.

In a letter to EPA Administrator Lisa Jackson, APHA and 17 other public health organizations applauded EPA’s decision earlier this year to reconsider the standards it set in 2008. The groups urged EPA to go farther and set standards that provide widespread protection to the health of millions of people, especially those most at risk.

Ground-level ozone, a primary component of smog, is produced by motor vehicle exhaust, industrial emissions, gas vapors and other sources, and can form in harmful concentrations in the air, particularly on hot, sunny days. The Clean Air Act requires the EPA to set National Ambient Air Quality Standards for ground-level ozone and other pollutants. The current standard is set at 75 parts per billion; APHA and its cosigners are urging a standard of 60 parts per billion.

According to the groups, science supports a stronger standard. “Clinical and epidemiological studies have shown that breathing ozone can cause adverse health effects at concentrations lower than the 75 parts per billion 8-hour average standard,” the groups wrote. Exposure can lead to respiratory and cardiovascular health effects, increase mortality and adversely affect sensitive groups, including those with asthma, seniors and outdoor workers. Children are particularly vulnerable.

The groups said, “Given the weight of evidence, we urge you to set the eight-hour ozone standard at 60 parts per billion to protect against known and anticipated adverse health effects and to provide a margin of safety as required by the Clean Air Act.”

To read the letter, visit To view EPA’s proposed revisions to the standards, visit