- [Instructor] Hey there, friends.
Today, we're gonna learn about air pollution.
And to start off, we're going back in time
to the small town of Donora, Pennsylvania,
in October of 1948.
(pensive harp music)
Walking into this small industrial town,
you can immediately sense that something is wrong.
It's the middle of the day,
but there's a thick yellowish smog everywhere,
enveloping everything and even blocking out the sun.
It's so dark that streetlights are on during the daytime.
It stings your eyes and it's hard, even painful to breathe.
What we're experiencing is the Donora Death Fog,
one of the worst air pollution disasters
in the United States.
Donora was an industrial town full of steel plants and mills
which released toxic emissions,
such as hydrogen fluoride and sulfur dioxide
when processing steel and other metals.
Normally, these poisonous gases
would disperse into the atmosphere.
But this time, there was a temperature inversion,
which caused a blanket of warm air
to cover a layer of colder air near the surface
and ride over Donora.
Consequently, the toxic emissions
were essentially trapped under the warm air.
Over the course of several days
from October 26th to October 31st,
these toxic emissions had accumulated so much
that half of the 14,000 people living in Donora
suffered from respiratory problems and 20 people died.
Relief only came when the steel mills were shut down
and a rainstorm alleviated the smog.
But following the deadly Donora smog,
the public began to realize just how dangerous
and life-threatening air pollution could be,
and citizens demanded change.
Donora became a turning point in US history
and was a start of the clean air movement.
The Air Pollution Control Act of 1955
was the first piece of US federal legislation
involving air pollution and provided funds
for research about air pollution.
Then, in 1963, the Clean Air Act was passed,
the first federal legislation to control air pollution,
and later expanded in 1970, which resulted in the creation
of the US Environmental Protection Agency, the EPA,
to develop and enforce regulations
to protect the general public
from exposure to major outdoor air pollutants.
The Clean Air Act was expanded in 1977 and again in 1990.
And throughout its nearly-60-year history,
our air quality has drastically improved
and pollutants have dropped sharply.
Since 1990, major air pollutants such as carbon monoxide,
nitrogen oxides, sulfur dioxide,
and volatile organic compounds have greatly decreased,
and that's just since 1990.
These four main air pollutants that I highlighted
are largely released as emissions from burning fossil fuels,
which comes from driving vehicles
and operating coal-fired power plants
and other industrial facilities.
So, as we've started to drive more efficient vehicles
and obtain more energy from clean renewable sources,
we've decreased the amount of fossil fuels that we use.
And in turn, we've reduced emissions
from fossil fuels and associated air pollutants.
But how does the Clean Air Act work exactly?
How do we clean the air
and limit emissions of harmful pollutants?
Clean Air Act regulations implemented by the EPA
have led to new technologies that help to limit emissions
and remove pollutants from the air.
In particular, many of these technologies
help to reduce air pollution
from coal-burning power plants and vehicles.
Each of these pollution-control technologies
functions to remove harmful components out of emissions
and release a less harmful substance.
In the last decade or so, you've also probably noticed
more and more electric vehicles on the road.
Improving the fuel economy of vehicles
and even using battery-powered electric vehicles
can reduce the need to burn as much gasoline,
thereby reducing emissions and giving us cleaner air.
A good example is the growing demand
for hybrid and purely electric vehicles.
Here we have a simplified figure
that explains the sources of energy
for different types of vehicles
and their respective emissions.
On the left, we have conventional vehicles,
which rely on fossil fuels such as gasoline or diesel
and, when driven, produce lots of emissions
like carbon dioxide and air pollutants.
Hybrid and plug-in hybrid vehicles
are similar to conventional vehicles
in that they have an internal combustion engine,
but they also have an electric motor
which uses energy stored in batteries.
These batteries can be charged by regenerative braking
or, in the case of plug-in hybrids,
just by using a wall outlet or other charging equipment.
In turn, because these hybrid cars
are partially fueled by batteries,
they produce fewer emissions than a conventional car.
Finally, vehicles that rely solely on electricity,
known as battery electric vehicles or BEVs,
can use an alternative electricity source
so that there's no emissions
at the source of the electricity.
What else can we do to ensure cleaner air?
We can reduce our reliance on fossil fuels
and instead invest in cleaner renewable resources
to generate electricity such as geothermal, wind, and solar.
And we can make decisions in our day-to-day lives
to reduce or prevent air pollution
by using less energy and alternative fuels.
For example, walking, biking, or using mass transportation
can reduce the need to burn fossil fuels.
And there are plenty of other ways
to reduce our electrical needs;
in particular, using more energy-efficient appliances.
For example, think of the LED bulb,
which uses 75% less energy than incandescent lighting.
So, even switching out bulbs
in the lights around your house or apartment
can make a huge difference.
But there's still many other places out there like Donora,
and oftentimes folks living in cities
with heavy air pollution literally can't afford to leave.
There's still much work to be done.
In Donora, though, there's the Donora Smog Museum,
which has the tagline "Clean air started here."
The terrible incident suffered by Donora's community
played a huge and pivotal role
in opening the eyes of Americans
to the hazards of air pollution and spurred political action
that's carried forth through today
and will continue into the future.
Let's all take a deep breath and be glad that we can.