Along with summertime heat and long hours of intense sunshine comes higher levels of ozone pollution. This is the "bad ozone" in the air we breathe, not the "good ozone" in the upper atmosphere that provides protection from ultraviolet rays. An extensive body of scientific information has documented health problems related to ozone pollution, including premature death, hospital admissions for heart and respiratory problems, more frequent asthma attacks, and emergency room visits for respiratory problems. Ozone also causes breathing problems for outdoor workers and people exercising outdoors, as well as for children and older adults.

While some progress has been made over the past several decades in reducing this pollution nationally, efforts to reduce ozone have lagged considerably behind improvements in other widespread air pollutants. In the period between 1990 and 2012, national ozone pollution levels have declined only 14 percent, compared to 75, 72, and 39 percent drops in carbon monoxide, sulfur dioxide, and particle pollution, respectively.

The U.S. Environmental Protection Agency (EPA) provides information to the public on daily air quality based on the Air Quality Index (AQI). The AQI is a color-coded tool linking air pollution levels to the severity of potential health impacts, based on national air quality standards. Air quality at or up to 50 percent below the national standard is classified as "moderate," meaning it's designated as healthful for most people, although EPA acknowledges that "for some pollutants there may be a moderate health concern for a very small number of people. For example, people who are unusually sensitive to ozone may experience respiratory symptoms."

So what's the problem? First, a bit of history. The Clean Air Act requires that EPA set air quality standards at levels "requisite to protect public health," allowing for an adequate margin of safety, and that these standards be reviewed and, if needed, revised at no more than five-year intervals. However, the current ozone air quality standard, adopted in 2008 under the Bush administration's EPA, disregarded the recommendations of the agency's independent scientific advisors and set the standard above even the top end of the range recommended by the advisory committee. In response, the advisory committee sent then-EPA Administrator Stephen Johnson a letter noting that his decision "fails to satisfy the explicit stipulations of the Clean Air Act that you ensure an adequate margin of safety for all individuals, including sensitive populations."

Not surprisingly, public interest organizations led by the American Lung Association sued EPA over this wrong-headed decision. The litigation was put on hold when Lisa Jackson, the Obama administration's first EPA head, noted that the Bush-era ozone standard was legally indefensible and initiated an expedited review process. That process resulted in a 2010 proposal for a more protective revised standard that was consistent with the science advisors' recommendations and reflected current science. However, this effort was subsequently undercut by a September 2011 White House decision to halt the review process and wait for completion of the regular five-year review cycle, which should have occurred in 2013. EPA missed the five-year review deadline and is now under a court order to propose its decision on the ozone standard by Dec. 1, 2014 and complete its review by Oct. 1, 2015.

EPA's draft staff recommendations have again called for a more protective ozone health standard consistent with the range originally proposed in 2010. However, EPA's science advisory committee has updated their assessment of the current science and recently indicated that, at the high end of the staff's proposed range, there is "substantial scientific evidence of adverse effects…including decrease in lung function, increase in respiratory symptoms, and increase in airway inflammation. The advisory committee also notes that the upper end of the staff's suggested range "may not meet the statutory requirement to protect public health with an adequate margin of safety" and that somewhat lower levels would offer more public health protection and a greater margin of safety.

Unfortunately, due to decisions in both the Bush and Obama administrations, EPA's past failures to revise the ozone standard based on the scientific evidence rather than political concerns has meant that for the past six years, the public has been misled into believing that air quality that meets the current ozone standard actually protects their health. As EPA's own science advisors have been telling them for more seven years, breathing air with ozone pollution levels at or even below what is now deemed healthful actually presents substantial public health risks.

Industry and its proxies in Congress have already begun their drumbeat of messages asserting devastating economic consequences should EPA adopt a more health-protective standard, conveniently ignoring studies finding relatively small impacts on the overall national economy from past improvements to air quality standards, as well as the fact that the U.S. Supreme Court has definitively ruled that EPA is precluded under the Clean Air Act from considering implementation costs when setting air quality standards.

Let's hope that this time, EPA can escape political interference and finally adopt a new ozone standard that adequately protects public health and provides the required safety margin, especially for those most vulnerable to ozone's impacts.