With residents of cities like neighboring Nashville living with high levels of smog, eyes are on the Environmental Protection Agency and its pending decision on whether to strengthen emission limits. Smog is a byproduct of tailpipe and industrial emissions and the EPA is debating a tougher limit of 60 parts per billion, instead of the current limit of 75.

The American Public Health Association's executive director Dr. Georges Benjamin says at current levels, smog is linked to a number of health problems. "It exacerbates people with asthma and chronic obstructive pulmonary disease, and it causes not only just these attacks, but can cause premature death and other morbidity," says Benjamin. "It's a significant problem and we can address it by reducing the amount of ozone produced."

Some industry leaders say the current standard is effective but Benjamin says there is solid science showing it isn't strong enough. Public hearings wrap up today in California, but written comments can be made until March 17.

Last year, the American Lung Association ranked Nashville as the 29th most polluted metro area in the nation for smog. Both Davidson and Sumner counties received a failing grade for their air quality. Pulmonary physician Dr. Dona Upson associate professor of Medicine at the University of New Mexico testified at one of the hearings last week. She says the limit will go a long way in protecting public health. "The EPA's analysis has shown that setting a standard at 60 parts per billion would prevent up to 7,900 premature deaths, 1.8 million asthma attacks in children, and 1.9 million missed school days each year," says Upson.

According to the American Petroleum Institute, the stronger limit would be expensive. But the American Lung Association's senior vice president for advocacy and education Paul Billings says the standards are not set based on cost, but on the levels at which this type of air pollution is considered dangerous. "You want your doctor to tell you what makes you sick, not what it'll cost to cure you," says Billings. "So, the API is really at the wrong part of the process. Cost and feasibility come into the conversation when we try to meet these standards, what strategies are employed."

The standard has not been updated since 2008 and a final rule is expected by Oct. 1.