EPA’s science advisers urge stricter limits on lung-damaging ozone

LOS ANGELES — A committee of scientific advisers has urged the U.S. Environmental Protection Agency to adopt a tougher federal standard for ozone, saying current limits on the lung-damaging pollutant fail to protect public health.

A letter sent Thursday by the EPA-chartered Clean Air Scientific Advisory Committee recommends strengthening the federal standard for ozone, the main ingredient of smog, to below 70 parts per billion and as low as 60 ppb. That range is significantly stricter than the current limit of 75 ppb, set in 2008 during the George W. Bush administration.

The independent panel of experts says there is “ample scientific evidence” that ozone is harmful at lower levels than previously thought. It cites studies showing that even ozone-polluted air at 72 ppb can cause adverse health effects for young, healthy adults after a little more than 6½ hours of exposure.

Ozone, a corrosive gas that forms when pollutants from burning fuels bake in sunlight, inflames the lungs and can damage the airways and aggravate asthma and other respiratory illnesses.

In 2010, the EPA estimated that setting the ozone standard at 60 ppb would avoid 4,000 to 12,000 premature deaths, prevent 21,000 hospital and emergency room visits and cut missed work and school days by 2.5 million per year. Those health benefits would drop significantly if the standard were set at 70 ppb.

In 2011, President Barack Obama went against the recommendations of the EPA and its scientific advisers and halted a proposal to lower the nation’s ozone standard to a level between 60 ppb and 70 ppb.