I asked a colleague of mine from the Somerville Transportation Equity Partnership, Wig Zamore to respond to Thera's email because he has been looking at the health effects of bicycling on busy roadways. We work together on the CAFEH studies examining health impact of near roadway pollutants ( http://sites.tufts.edu/cafeh/ ). Wig has co-taught a course at Harvard School of Public Health that focuses on active transportation (biking) and mobile pollution. His response to Thera's concerns may be of interest to others on the listserv. Ellin ---------- Forwarded message ---------- From: wig zamore <wigzamore(a)gmail.com> Date: Tue, Nov 5, 2013 at 7:02 AM Subject: Re: [H+T--Friends] AQ Impacts vs Active Transport Benefits To: Ellin Reisner <reisnere51(a)gmail.com>om>, Thera Black <blackvt(a)trpc.org> Hi Ellin and Thera, I can supply some papers that may be helpful. In general most environmental health scientists are pro "active transportation". Although some active transportation epidemiology has used regional pollutants such as PM2.5 in their analyses (Barcelona for example), the better question is whether primary transportation emissions such as ultrafine particles, particle bound polycyclic aromatics and transition metals are a health risk to joggers and bicyclists. These are a result of local conditions and not so much of regional pollution. You can have a very clean region but be next to a very busy roadway and have elevated risk. With traffic generally, you can think in terms of a few common sense metrics - how large is the volume (I5 in Olympia is up to 140,000 vehicles per day, SR101 considerably less and I do not have local street volumes), how close are people (10 meters, 100 meters, a kilometer), how much time do people spend there (home is worse than work and school, etc.), are there meteorological issues such as inversions, and finally are there street canyons or geographic features that might trap the pollution. With bicyclists, the issue is ventilation. Cyclists have about 4 to 6 times the effective dose as non-active travelers in the same corridors. Their breathing rates and metabolic rates are higher and the ultrafines are inhaled more deeply. For residents within 100 meters of a very busy roadway, good rules of thumb are that cardiovascular mortality risk, lung cancer risk, and childhood asthma risk are greater than 50% higher than cleaner locations in the same communities. Autism risk appears to be more than 100% higher for children whose mothers spent their whole pregnancies in such locations, or even a little higher for those children who spent their first year of life in high traffic exposure locations. In general these exposures occur to about 5% to 10% of urban populations and probably somewhat less in smaller cities. For active transportation participants, including bicyclists, the most obvious risks are cardiovascular. For susceptible populations, for example men who are proactively exercising after heart attack survival, the oxygen crisis stress levels in the heart muscles ( as measured by the ST segment of an electrocardiogram) may be doubled in the presence of diesel emissions. Similarly, heart attacks may be more common for everyone (3X) after high traffic exposures and may be a little higher for bicyclists (4X). Even so these events are relatively uncommon - people are not dropping like flies. Time of day makes a difference too. Cyclists should avoid highway and arterial adjacent travel during rush hours, where it is possible to do so. Ditto for very busy intersections. My personal advice would be to be to push active transportation as much as possible but to offer alternatives to the highest exposure routes when and where it is possible to do so. I have a breakfast meeting but will send along to Thera some relevant papers a little later today. Regards, Wig Zamore Email or 617-625-5630 (24/7 secure land line, no cell) On Tue, Nov 5, 2013 at 12:24 AM, Ellin Reisner <reisnere51(a)gmail.com> wrote: -- Ellin Reisner, Ph.D. reisnere51(a)gmail.com