Some Thoughts on Near Roadway Air Pollution and L.A.’s Future

From Rob McConnell's presentation: air pollution spikes at freeways

From Rob McConnell’s presentation: air pollution spikes at freeways. Pollution levels drop quickly away from freeways.

I attended a forum event yesterday, entitled “The Collision of Best Intentions: Public Health, Smart Growth, and Land Use Planning.” Speakers focused  on “NRAP” – an acronym I wasn’t familiar with. NRAP stands for Near Roadway Air Pollution. It’s the study of pollution risks near freeways and other high-volume roads.

I confess that I have been only vaguely aware of NRAP. Years ago, I had heard about studies that show health issues correlate to areas close to freeways. I vaguely recall some efforts to keep schools at a tolerable distance from freeways. I am still not all that up to speed on this issue, so apologies if I have characterized anything incorrectly in this article.

The fundamental question that this conference explored was, basically: In the light of air pollution issues, is urban densification good for overall health? There are a number of corollary issues: On congested-polluted streets, is bicycling or walking healthy? Is Transit-Oriented-Development, or, more generally, infill development bad for our health?

For me, a car-free bike activist, these questions go to my fundamental core. Of course bicycling and walking are good! For me, for my community, my planet. I think that there’s a body of research that backs me up. Cyclists live longer than non-cyclists. Health benefits of cycling outweigh risks by 20:1, according to a London study. Inactivity is dangerous, in the long run. There’s also research showing that car occupants are exposed to unhealthy air quality inside cars, so, even if bicycling exposes me to roadway air pollution, I don’t think I am at any greater exposure than other folks using the road. And cyclists and pedestrians are on the edge of that pollution cloud, not in the thick of it the way drivers are.

I suspect that a lot of people make poorly informed decisions based on perceived risk. The most common example is that of the person who drives to their destination because they afraid of flying. Flying is, statistically mile-for-mile, way safer than driving.

I haven’t seen a clear study on this, but I tend to think that a similar ill-informed trade-off takes place with driving and bicycling. Replacing a perceived-dangerous ~10mph bicycle trip with a perceived-safe 50+mph car trip may well put a well-intentioned person at greater risk. Not bicycling in a polluted city, while instead driving in a polluted city doesn’t make good sense to me. My hunch is that it’s a similarly false trade-off, like driving instead of flying.

Back to yesterday’s forum.

From Rob McConnell's presentation: Asthma is worse closer to major roads.

From Rob McConnell’s presentation: Asthma is worse closer to major roads.

USC’s Rob McConnell presented on research that found clear relationships between proximity to freeways and rates of asthma and obesity. Apparently, historically, there was a general understanding that regional air pollution made asthma worse, but didn’t cause it. The current understanding is that roadway pollution causes asthma. Watch a similar talk by Rob McConnell here. McConnell also reviewed research linking NRAP with increased obesity.

These very real heath risks led researchers to investigate solutions. UCI’s Doug Houston spoke about a review of various structural tinkering to mitigate roadway pollution. Researchers have looked to soundwalls, sealed windows, taller building, vegetation, indoor air filtration, and more. Though those measures help, none of them quite solves the problem.

When there’s no airtight mitigation, health leaders turn to the solution that I mentioned above: keep people away from freeways. Don’t locate homes, schools, parks, work-sites, etc. within a 400 meter (~1200 foot) buffer of freeways.

I tend to think that this buffer approach results in a vicious cycle. Creating freeway buffers will spread things out even more, making for longer trips which are more difficult to walk and bike. Driving more for more trips increases traffic congestion. Congestion leads to road widening. Widening (and increased traffic volumes) means moving that initial buffer outward, compounding the problem.

As I was listening to all this, I felt like there was too much emphasis on dealing with our car-centric system as a given. Car-choked freeways are just part of the way god made our cities. We, health professionals, are just doing our best to adjust to the system we find ourselves stuck in. The discussion was all about how to keep people out of the way of pollution, but not to look at reducing or eliminating that pollution at its source. It’s as if health professionals looking at the tobacco problem just assumed that smoking happens everywhere, and then spent a lot of effort studying gas-masks for non-smokers. Taking on tobacco is a great public health success – because health professionals were able to ban tobacco from many places, and to stigmatize tobacco based on its threat to health.

(I also think that an overly narrow focus on near-roadway-air-pollution makes us miss other huge health risks associated with cars. Every year, driving kills 30,000+ people in the U.S., 1.5 million worldwide. There are greenhouse gases, water pollution, noise pollution, obesity, and plenty more issues.)

I was glad to hear Occidental College’s Mark Vallianatos, commenting from the floor microphone, suggest an important alternative. Instead of moving people away from roads, let’s change our roads to be safe for people. If we have schools, playgrounds, housing, etc. adjacent to a road, then, for the sake of health, let’s design and regulate that road to limit vehicle emissions to safe levels. Let’s traffic-calm and road diet our arterials, downgrade our freeways, hopefully get rid of, at least, some of them.

Reducing car capacity isn’t politically easy. It may not work everywhere right now, but, going back to what the forum was addressing, I think it’s important for our core urban neighborhoods. It’s important for the places where we’re trying to make smart growth and TOD work. If health professionals are questioning the health effectiveness of smart growth, of walking, and of bicycling, then we need to also question the unhealthy car-centric systems that surround and endanger these solutions.