Air Pollution: Bad For Health, But Good For Planet?

Cleaning up the air, while good for our lungs,
could make global warming worse. That
conclusion is underscored by a new study,
which looks at the pollutants that go up
smokestacks along with carbon dioxide.
These pollutants are called aerosols and they
include soot as well as compounds of nitrogen
and sulfur and other stuff into the air. Natalie
Mahowald, a climate researcher at Cornell
University, says so far, scientists have mostly
tried to understand what those aerosols do
while they're actually in the air.
"There are so many different kinds of aerosols
and they have many different sources," she
says. "Some warm and some cool. But in the
net, humans are emitting a lot of extra
aerosols, and they tend to cool for the most
part."
“
As we clean up the aerosols, which we really
want to do for public health reasons, we are
going to be perhaps causing ourselves more
trouble in terms of the climate situation.
- Natalie Mahowald, climate researcher, Cornell
University
The aerosols reflect sunlight back into space,
or they stimulate clouds that keep us cool. But
it turns out that's not all they do. These
aerosols also influence how much carbon
dioxide gets drawn out of the air by plants on
land and in the sea.
"They can add nutrients, for example, to the
oceans or to the land," Mahowald says. "But
also while they're in the atmosphere they can
change the climate, and so that also can
impact the amount of carbon the land or the
ocean can take up. So there are quite a few
different ways that aerosols can interact."
In an article published in Science magazine,
she concludes that those effects add up to
quite a bit. At the moment, aerosols are not
only helping reduce global warming by cooling
the atmosphere, but they're helping reduce the
amount of carbon dioxide that stays in the air
once we emit it.
That's good news for now — it means the
planet isn't heating up quite as fast as it could.
But that's bad news looking down the road a
little bit. That's because many aerosols make
people sick — heart and lung disease in
particular. So some nations are now in the
process of trying to rein them in.
"As we clean up the aerosols, which we really
want to do for public health reasons, we are
going to be perhaps causing ourselves more
trouble in terms of the climate situation,"
Mahowald says.
This is not a brand-new idea. For example,
other research has found that switching from
coal to much cleaner natural gas might not do
much to help with global warming because it
would also be reducing the pollutants in coal
smoke that help offset warming.