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.
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.