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.
---------- 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>, 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:
> Do you have any suggestions for good articles on this or presentations
> that can be sent to Thera Black?
> ---------- Forwarded message ----------
> From: Thera Black <blackvt(a)trpc.org>
> Date: Mon, Nov 4, 2013 at 4:00 PM
> Subject: [H+T--Friends] AQ Impacts vs Active Transport Benefits
> To: "h+t--friends(a)ryoko.chrispy.net" <h+t--friends(a)ryoko.chrispy.net>
> Greetings, all - I’m reaching out to Health and Transportation listserv
> members in the hopes someone can point me in a productive direction.
> I have a planning commission that is struggling with the public health
> benefits/impacts of compact, walkable urban development. On the one hand
> they understand and appreciate the active transportation benefits
> associated with this built form. On the other hand, the epidemiologist on
> the commission argues that the increased impacts of air pollution in an
> urban area more than offsets the benefits associated with active lifestyle
> and so is working to prohibit urbanization measures along our key transit
> corridors – density, mix of uses, transit oriented development.
> I can find reams of articles on the benefits of active transport. And I
> can find scholarly articles about transportation-related air quality
> impacts on public health. What I cannot find is anything that brings the
> two together in a way that sheds light about these considerations in
> combination – air quality impacts trumping active transport benefits (or
> vice versa). This is further complicated by the studies she is referencing
> which were done in major metropolitan areas. We are a small, low-density
> metro area with a population of about 175,000 between three cities. Our
> principal arterials carry anywhere from 10,000 – 18,000 vehicles per day.
> We have very little “urban” land use form and are trying to more
> effectively stimulate that kind of private sector investment along our
> premier transit corridors where we have the beginnings of walkable,
> mixed-use neighborhoods taking shape.
> Are you aware of any research that has looked at the trade-offs between
> active transport and air quality impacts that might be useful in this
> Any insights are appreciated – thank you!
> Thera Black
> Thurston Regional Planning Council
> 2424 Heritage Court SW, Ste A
> Olympia, WA 98502
> 360.956.7575 ext 2545
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> H+T--Friends mailing list
> Ellin Reisner, Ph.D.
Ellin Reisner, Ph.D.
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