Good planning is good public health policy. Why do I say this? As a pediatrician, I see first-hand the negative health impacts of sprawl development on our children, whose asthma is worsened by air pollution caused by too much driving. Medical professionals have known that cities designed primarily around driving are responsible for traffic pollution and congestion; contribute to climate change; and limit opportunities for healthy, active lifestyles. Now the Southern California Association of Governments is considering the future of growth in our region, in the context of its “Sustainable Communities Strategy.” I urge local and regional leaders to get involved in this process and actively promote good planning for our region that allows us to grow in smarter and healthier ways.

The most important thing we can do for our health is to reduce our reliance on driving. Cars and other mobile sources are responsible for 75 percent of the damaging air pollution in our region.

In San Bernardino County, ozone and soot continue at epidemic levels. in the American Lung Association 2011 State of the Air Report, San Bernardino County ranked as the most polluted county in the United States for ozone levels with Riverside County close behind. This dirty air harms all San Bernardino County residents, but especially the 111,000 people with asthma, including 40,000 of our children. Asthma is the most common reason for school absence from a chronic illness, and pollution increases the frequency and severity of asthma attacks.

For physicians, there are few needs as urgent as making sure that the air we breathe in Southern California isn’t making us sick and contributing to escalating health care costs. We see too many children suffering from asthma attacks and respiratory illness made worse by poor air quality.

New analysis by the American Lung Association in California confirms the huge clean-air and health benefits of smart growth strategies that reduce driving in Southern California. “Growing Healthy in Southern California” reports that reducing traffic by 20 percent can save more than $16 billion in health and societal costs between now and 2035 and avoid thousands of asthma attacks and respiratory symptoms. This translates into savings of $1 billion in the year 2035 alone. These dramatic health savings are in addition to the benefits we will experience from cleaner vehicle technologies on the road in the next two decades. Based on these findings, communities can rest assured that smart growth measures like expanding transit and other alternatives to driving will show a tremendous payback in health and dollars.

SCAG released its Sustainable Communities Strategy in early December and is seeking public input for a vote in April. This poses an important choice for Southern California leaders and the public.

Will our local leaders vote to achieve the greatest health benefits for our region? If so, they must join with the hundreds of public health professionals who support a new vision for growth in Southern California that will improve the lives of generations to come.

Decision makers should support expanded public transit options; urban design that centers new growth around transit corridors; increased funding and support for “active transportation” including more bicycle and pedestrian infrastructure; and more strategies to reduce diesel pollution from goods movement.

Billions of dollars in health savings can be realized by choosing the strongest possible smart growth strategies. This will have a direct impact on the health of every family who lives and breathes in Southern California.

Southern California needs to break the habit of business-as-usual sprawl and move forward with the strongest possible prescription for healthier communities. Only then can we achieve the goal of cleaner air that will not make our children sick.

Sunil Saini, M.D., an allergy-asthma specialist practicing in the Inland Empire, is associate clinical professor at University of California, Irvine.