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Health Department

Dr. Paul's Tennessean Guest Column - April 14, 2008

Traffic jam on InterstateIn the upper atmosphere an ozone layer protects us from radiation, but here at ground level ozone is the main ingredient in smog. Ozone is a powerful irritant at the levels frequently found here and in many other cities. Health effects include shortness of breath, chest pain when inhaling deeply, wheezing and coughing, and worsening of asthma and other lung diseases. New research linking death rates with ozone levels in the US has confirmed that breathing ozone over a short period can increase the risk of premature death.

The air in middle Tennessee has met the Environmental Protection Agency’s Ozone Standard for the past four years, but the target is changing. Last week, the EPA released its new standard, moving it from 84 parts per billion to 75.

Environmentalists were dismayed that the EPA's decision did not set the standard at 70 parts per billion as recommended by its own expert panel. Indeed, to optimally protect health we would want stricter standards. However, the Nashville region has serious work to do in setting forth and implementing a plan to achieve even the 75 parts per billion standard. .

Very simply, most of our ozone problem results from a mix of motor vehicle exhaust and summer weather. To meet any new standard, we will have to continue to enforce controls on motor vehicles and other sources of pollution. Replacing older, ‘dirtier’ vehicles with newer, cleaner vehicles will help.

But to really achieve cleaner and healthier air, we’ll need to pay attention to how we get around. A recent report ranked this area second in the nation in vehicle miles traveled per capita. Over 56 million vehicle miles are traveled daily here—about 14,400 miles per person per year. Congestion on the roads is a quality of life issue, it contributes to greenhouse gases and climate change, and many of us drive everywhere and rarely if ever walk or ride a bicycle, or partake in other healthy physical activity. Obesity is epidemic in part because we drive so much and walk so little.

Many of our neighborhoods and routines were designed around the automobile, so there aren’t quick fixes. However, individuals, organizations, employers, and governments can all work to create an environment and culture that foster fewer vehicles on the road. Support of rail and bus transit, greenways, sidewalks, neighborhoods near workplaces, and incentives for employees who don’t drive alone to work will help clear the air and save lives in the long run.

William S. Paul, MD, MPH
Director of Health
Metro Public Health Department of Nashville/Davidson County