[MUSIC PLAYING]
LUKE GROSKIN: Pedaling through the streets of New York City
can be physically and mentally thrilling.
And for many, it's the most exhilarating part of their day.
DR. DARBY JACK: When I commute by bike,
I ride from the Clinton Hill neighborhood
up to the Columbia Medical Center.
Two small kids at home, I don't have
a lot of other chances for exercise
so it's definitely a work out.
LUKE GROSKIN: And for Dr. Darby Jack,
cycling through urban canyons is more than a routine.
It's a potentially trailblazing field of study.
DR. DARBY JACK: To characterize the health consequences
of riding a bike in New York City.
LUKE GROSKIN: We all know the risks of navigating traffic
on a bike.
Instead, Dr. Jack and Dr. Steven Chillrud
of Columbia University, are more interested in the dangers
we can't just avoid and we can't see.
DR. DARBY JACK: Most people who ride their bike in New York
have had the experience of being stuck behind an idling FedEx
truck or whatever it happens to be
and them getting an obvious large dose of pollution
from that.
DR. STEVEN CHILLRUD: So as you move through a city
you have air pollution that comes from far away,
from the Midwest where a lot of the electricity is generated,
and then you have your local sources
from space heating to traffic.
There's a lot of soot.
There are black carbon and polycyclic aromatic
hydrocarbons, metals.
LUKE GROSKIN: Lots of nasty stuff you definitely
don't want in your body.
DR. STEVEN CHILLRUD: For the longest time,
most studies relied upon these air
monitors that have been on rooftops, far from sources,
and have really been done primarily on ambient levels,
totally ignoring the fact that people
are breathing at very different rates throughout their day.
So that's kind of our overall arching hypothesis,
is that if you're an active person and exercise,
you should be looking at dose and not looking
at just the concentration.
LUKE GROSKIN: The problem was that monitoring someone's
exposure level and physical activity at the same time
just wasn't technologically feasible.
DR. STEVEN CHILLRUD: It's just been within the last few years
where you've had devices that are small enough,
that are comfortable to wear around everywhere you go.
LUKE GROSKIN: Now armed with miniaturized monitors,
Dr. Chillrud and Dr. Jack are partnering
with their local public radio station, WNYC,
to recruit dozens of riders to act as mobile Guinea pigs.
DR. DARBY JACK: We asked study participants
to wear our kit five times in a two-week period.
LUKE GROSKIN: During that time, the kit
will gauge their blood pressure, heart rate and breathing
rate, breathing volume, as well as minute-by-minute exposure
to particles in the air.
DR. STEVEN CHILLRUD: Air comes in
through this side selective inlet, it comes down
and it puts the particles onto a filter,
and it looks at how much light gets through that filter.
LUKE GROSKIN: Finally, the test subjects
launch a GPS app that will capture geographic data
across each borough.
And just to be sure these new-fangled monitors are
measuring accurately, each participant and their equipment
are brought into a lab and put through their paces.
Dr. Chillrud kindly demonstrates for us.
SPEAKER 1: We're measuring ventilation.
We're measuring how much volume he moves in and out
of his lungs and at what rate.
And then we're going to compare that
to the values that are being obtained with the vest
so we can make sure that what the vest is measuring out
in the field is actually accurate.
The more vigorously that you exercise,
the deeper you're going to breathe,
the harder you're going to breathe,
and then there's going to be greater
exposure to whatever pollutants are in the air, theoretically.
So you can hear how deep, how hard he's breathing.
Steve is breathing right now at about 120 liters per minute
so he's taking in a lot of air right now.
DR. DARBY JACK: We hypothesize that
these short-duration exposures that occur during commuting
will have an effect on your heart-rate variability,
and then, number two, that we hypothesize
that it will cause an ephemeral increase in blood pressure.
LUKE GROSKIN: They also hope to identify spots
throughout the city that you might want to avoid.
DR. DARBY JACK: When you're in those street canyons,
the air just sits there.
The air doesn't move around and so
all the particles that get admitted from tailpipes,
they stay.
They stay around.
LUKE GROSKIN: Conversely, the breezy banks
of the Hudson or the East River should have less pollution
despite the proximity to major roadways.
DR. DARBY JACK: So we're going to pool all the data
and create maps that will show the variation
over space and over time.
LUKE GROSKIN: Although the data may eventually
show dramatic increases in how much pollution
you breathe in while exercising, Dr. Chillrud
cautions that their goal isn't to dissuade bike riding.
DR. STEVEN CHILLRUD: The exercise is good.
You know, that's been shown over and over
and over again that exercise leads to a healthier life.
But the question is, can you do that exercise
either at certain times of the day,
or can you do it in certain parts of the city?
Can you choose your route to avoid and limit
your exposure that way?
LUKE GROSKIN: There may even be policies
that cities can implement to reduce exposure.
DR. DARBY JACK: It's a five-year grant and we're about halfway
through year one, so it's a long-term project.
LUKE GROSKIN: And you can actually take part.
DR. DARBY JACK: Yeah, go to WNYC.org/streets.
LUKE GROSKIN: To find out more and learn about future biking
projects.
For Science Friday I'm Luke Groskin.