If you look at the Automobile Club of Southern California's 1937 freeway plan for Los Angeles, you'll see that the relationship between the freeways and the city evolved a bit differently from the way the people who wrote that plan envisioned.

The original idea was that wide greenbelts would separate the freeways from the city around them. When the freeways came in the decades that followed, of course, they were bulldozed right through the neighborhoods, often with houses adjacent. And now that land is expensive and housing is scarce, infill developers – and planners – are looking to areas adjacent to freeways to build infill housing.

Could we go back to the greenbelt idea? That seems to be the viewpoint of a growing number of public health experts. A couple of months ago, I wrote a column in CP&DR about the public health risks of building infill housing near freeways. Last Friday, May 11, I was on a panel with several of the public health experts at the UCLA Extension "Urban Renaissance" conference at the Biltmore in downtown Los Angeles.

One of the most provocative speakers was Andrea Hricko, a professor at USC's Institute for Preventive Medicine in Alhambra. She was one of the authors of the recent academic article that I wrote about, which concluded that children living close to freeways are at risk of having diminished lung capacity. Using a series of slides showing housing projects and schools adjacent to freeways and truck routes, Professor Hricko argued forcefully in favor of large buffer areas around freeways and other transportation corridors where toxic air pollutants might be concentrated.

From a purely public health perspective, this makes sense. But is it practical? The land adjacent to freeways in Los Angeles is among the most expensive real estate in the world. Can we really move all the housing – and probably everything else as well – 500 yards away?

Of course not. And in the Q&A, Professor Hricko talked a little bit more about possible "mitigation" strategies rather than "avoidance" – for example, building filters or traps on the freeways so that they capture some of the toxic pollutants.

But maybe one thing we can do is discourage the construction of housing, especially family affordable housing, alongside the freeways. An affordable housing developer in the audience pointed out that one of Professor Hricko's bad examples – an affordable project with a child-care center right up against the 710 Freeway – actually got a perfect score in the rating system from the state Low Income Housing Tax Credit Allocation Committee. In that system you get points for proximity to schools and transit – and apparently no penalty for being next to a truck-intensive freeway.

- Bill Fulton