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Science & Policy Update June 2014: The Built Environment

Walkable Cities: Healthy or Unhealthy?
By: Monika Shankar, Health and Environment Associate

Cities are becoming more walkable. And according to a report released June 17th by SmartGrowth America and George Washington University, Los Angeles is on the cusp of becoming a ‘major’ walkable city (check out this Los Angeles Times article detailing the LA case study). Planning and developing LA with a more robust pedestrian infrastructure could potentially begin to reverse decades of sprawl culture, which led to a maze of highways crisscrossing the city’s expanse. This trend also helped to make LA one of the most air-polluted cities in America. However, introducing pedestrian infrastructure into an already auto-dependent culture presents a challenging situation: we want to be healthier by walking, but are we healthier if we walk breathing dirty air?

The health benefits of walking have been extensively studied. We know that walking, or active transportation, can have tremendous positive benefits for both physical and mental health. According to the American Heart Association, walking even 30 minutes a day can reduce the risk of coronary heart disease, improve blood pressure and blood sugar levels, reduce obesity, enhance mental well-being and reduce the risk of various cancers. But what if our cities encourage us to walk near polluting sources such as LA’s ever-present highways and freeways?

A recent report produced by the Massachusetts Institute of Technology and the MIT Center for Advanced Urbanism challenged the notion that un-encumbered active transportation infrastructure development produces only positive health benefits. The report questioned whether “creating a more multimodal transit system” would actually produce positive environmental and health outcomes? It bluntly acknowledges that the links between traffic congestion and health are obvious. For example, traffic pollution exposure has been linked to children’s asthma as well as increased risk of obesity formation. Another study reported the association of traffic-related air pollutants to cervical dysplasia, a precursor lesion for cervical cancer. And this is just the tip of the iceberg.

Los Angeles is absolutely on the cusp of changing its physical landscape. The city is focused on investing funds in transit oriented development, creating compact and dense neighborhoods, and putting a greater emphasis overall on health. But whether these changes via planning and growth will actually produce healthy outcomes is yet to be determined. To ensure healthy outcomes are met, public health advocates and planners will have to collaborate on crafting strong and comprehensive policies that truly grounds the growth of our city in health. Furthermore, more research will need to be conducted to generate innovative solutions to the air quality challenges associated with active transportation. PSR-LA is working in multiple spaces to ensure this is achieved, including our work on the Plan for Healthy Los Angeles and the South and Southeast Community Plan Updates. For more information, contact Monika Shankar at

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