- When you're in a room with another person,
chances are you're breathing in some of their exhaled air.
And if that person has a disease like COVID-19,
you could be breathing in infectious air.
As the US starts to move through new phases of the pandemic,
many states are starting to reopen indoor dining
and other shuttered indoor spaces.
Public health experts say it's way too soon.
But still, many restaurants and bars are moving ahead.
One way they're trying to keep things safer is
by improving the ventilation,
so that any potentially contagious exhales
quickly gust away.
But how do you test for ventilation?
One way is with a carbon dioxide monitor like this one,
our exhaled breath is full of carbon dioxide.
And we want there to be
as little exhaled breath in a room as possible.
So it's not a perfect check.
But we can use a CO2 monitor as a proxy
for how much potentially infectious air is around.
We wanna see how this space is we frequently visit stack up.
So equipped with the CO2 detector,
we're gonna hit the streets of Brooklyn, New York.
Hello.
- Hello.
- Before heading out, we checked in with Jose-Luis Jimenez,
a professor at the University of Colorado Boulder,
and an expert and how tiny disease causing particles
spread through the air.
- We're breathing the virus in, especially into situations
when we talk to someone very close especially without mask
or when we share the air in a room.
And ideally, we will have some kind of machine that will
start beeping when the vials in the air,
but that's not doable at first, but we have something else
that we can measure, we can measure carbon dioxide.
- [Nicole] He explained it the outside air naturally
has around 400 parts per million of co2,
anything above that,
and people's exhales are floating around.
The higher the number, the higher percentage of the air
is coming from other people.
So let's test this out.
So I'm just sitting in my apartment with me breathing on it,
we're up around 900 which is pretty high
concentrations of carbon dioxide.
So let's open the window and see if we can get
some air flowing and see how far that drops.
Okay, and so after some time with the window open,
it's dropped down to 542.
Ideally, we want as close to outside levels of co2
as possible, but that's a bit unrealistic Jose-Luis told us
because once you go inside at least some air
is going to be trapped.
He set a benchmark of around 700
is what we should be looking for.
We use 700 as a limit because it's pretty low.
An it's achievable in most places.
With all that in mind, I put on my coat and headed out
into the neighborhood.
(gentle music)
First stop the park.
We're gonna get as far away from cars as it's impossible
to do in Brooklyn.
So in the middle of Prospect Park,
we're at 445 parts related carbon dioxide.
We're in the middle of this field, though,
with no cars around, few people, so it makes sense
it dropped a little bit.
Next we hit someplace a little less vacant.
So right now we're right in the entrance to the subway.
We're at 483.
We're on the subway platform.
This is the Brooklyn Flatbush Avenue bound to Print.
So we're just in the subway car stop and the thing went up.
We spent the rest of the day wandering
through grocery stores, restaurants, and shops.
All total, we visited over a dozen places
and recorded our readings.
Here's what we found.
My local grocery store clocked in at 584 parts per million
of carbon dioxide.
A second grocery store was a bit higher, but under 800.
The first bagel shop was about 600.
And the second wasn't far off.
This is a second bagel store.
Most shops and bars even the ones with people eating inside,
range from around 500 to 700 parts per million.
One though, raise my eyebrows, an indoor bar with a reading
over 1000.
This is one of my favorite bars.
We ran our numbers by Jose-Luis who said,
they were for the most part, not concernedly high.
I think from their point of view of everyone's admission,
this is not bad.
We've been recommending to keep the levels below 700.
When we show the air in that, I see a few below 700 to 709.
The one that has that is like 1000 versus 900,
doesn't have to be concerning.
And that bar that was over 1000.
In some countries, that would be illegal.
- Like for example, either in one South Korea or Portugal,
before the pandemic it was not legal to be over 1000, right.
In the US that have not arrived yet.
Now these numbers have their limitations, for starters,
ventilation isn't the only measure of risk.
Picture two rooms.
One, full of masked people who aren't talking that much,
and another full of chatty, mask less people.
Both groups of people are exhaling co2
and the mask doesn't change that,
if it did we would suffocate, but the lively mask less room
would be riskier.
The numbers just don't show it.
You have 1000 ppm co2 in a restaurant
where people are talking with a mask.
That's more dangerous than you have 1000 ppm in a library
where people are not talking and they're wearing masks.
Also, none of the spaces we visited
were at their capacity limits.
On the day we collected data, New York City restaurants
were open at just 50% capacity,
but the places we tested looked even emptier.
So all of these spots could have greater co2 readings
at different times, but even with these limitations,
ventilation monitoring can be really useful to owners
of bars, restaurants and other indoor spaces.
They can see how many people can be inside before
carbon dioxide levels start to climb, that might ultimately
keep people safer than occupancy limits
because not every building is the same.
Like the two restaurants, one was very well ventilated,
and the other one is poorly ventilated.
Indoor dining will never be entirely safe,
but people are still gonna eat in restaurants,
if they're open.
Monitoring ventilation won't stop the spread of disease
but it can help owners and patrons manage risk,
and it can remind us all about strategies
as simple as opening a window.
It is cold. (Nicole laughing)
Really picked a great day for this.