It’s common sense that living near a freeway isn’t healthy. The pollution from the cars and grit from the roadway make for what most would term a wholly unpleasant experience. Unfortunately, the only places for infill development, not to mention quite a few SMART stations, are near Highway 101. Before any post-SMART buildings are built, communities in Marin and Sonoma need to take measures to mitigate these negative health effects, or we’ll simply be building health problems for the future.
Roadway pollution is almost entirely from tailpipe emissions, and most of the health effects are from particulate material, that brown smoke most recognizably seen coming out of large truck exhaust pipes. It’s nasty stuff (PDF), not only because the shape of the particles increases the risk of asthma and lung cancer but because they carry heavy metals, which can contribute to diminished brain formation in children. Gases, such as carbon monoxide, are less hazardous to the health of nearby residents.
These particulates, at least when they come from a freeway, are concentrated within 200 feet of the road, though they are measurable up to half a mile away during the day and 1.5 miles away during the early morning hours. In Marin, that means a huge portion of the county lives with 101’s pollution: all of San Rafael, most of Novato, Greenbrae, Mill Valley, Corte Madera and Larkspur, Marin City, and Sausalito lives within the freeway’s pollution plume. Only Ross Valley and West Marin don’t need to deal with the problem, though arterial roads generate their own plumes.