Claire Petersky wrote in part:
<< Does anyone have web references on air pollution
affecting bicycle commuters, and how to avoid it? When I run
a google search, I only get hits on how bike commuting
lessens pollution, which is not what I'm trying to find out
more about. >>
I am obsessed with this subject so I'll chime in here. I
don't think there's much out there in terms of good
information about this on the web. There is a lot of
educated guessing on exposure levels, risks, and avoidance
strategies. I do know of one study of cyclists' exposure, in
Southampton England in 1991, found that cyclists there were
sucking in, I don't remember, a good damn bit of CO.
...Beyond that there is much conjecture possible based on
the near- consensus that cyclists are likely to be exposed
to more pollutants than others, due to our propensity to
breathe deeply and meaningfully; and the multitude of
studies of non-cycling city- dwellers, some studies
involving folks walking around with personal dosage meters
to measure exposure to things like CO and NOx. Not on the
web as far as I know but P.G. Flachsbart analyzed and
summarized 90 of these studies in
P.G. Flachsbart, “Exposure to Exhaust and Evaporative
Emissions From Motor Vehicles,†in Schwela and Zali,
eds., Urban Traffic Pollution, pp. 89-126.
Basically, these studies tell us that concentrations of
pollutants vary wildly from one place to another within
urban areas, not just block by block but meter by meter, and
that the variances are somewhat predictable. It turns out
that the air near highways tends not to be as polluted as
the air downtown, where tall buildings keep pollution
trapped and stop-and-go driving creates more emissions.
Furthermore the air out in the middle of the street is going
to be worse than the air at the gutter, which in turn will
be much worse than the air 20 meters off to the side. Not
surprisingly, streets with more traffic volume have more
pollution, and the air in parking garages and tunnels has
the highest concentration of tailpipe emissions.
Given the predictable geography of traffic pollution, it is
clear that the best way to avoid it is to stay as far away
from traffic as possible--as long as that route doesn't
take you by the refinery. I think about half of our air
pollution still comes from fixed sources like refineries
and power plants.
Other strategies include inhaling through the nose,
effective against particulates. The nose is designed for
just that purpose but using it may require slowing down.
Also, micro-manage the breathing with the knowledge that no
two breaths are created equal. If you sense that there is
diesel soot or some other noxious substance entering your
airways, blow it out, hold out for a better gasp of air.
Diesel smoke is the worst. There are also little bits of
rubber floating around--tire dust. You thought PM-10 was
bad, now we have PM-2.5 to worry about. Sometimes I wish
these guys would just put away their microscopes. The good
news is that American air is better now than it was 20
years ago.
Robert
