hen we breathe in, air enters our nose where dust and other particles are
filtered out--the 1st line of defense. Here the air is warmed and moistened
before it travels down, past the throat, through the windpipe or trachea. The
trachea and other air passages are lined with a sticky mucus that traps germs
and particles before they enter our lungs--our 2nd line of defense.
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Impact on Health
Our
Amazing Lungs
Who's
Most at Risk?
What
Happens When We Breathe?
The
Nitty Gritty on the 6 Most Harmful Pollutants
Air
Pollution Advisories
What
the Scientists Say
Impact on Environment
Impact on Economy
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Special
cells called cilia have tiny waving hairs that push this mucus up and out of
our lungs along with all the pollution it has trapped--our 3rd line of defense.
After the air flows down the trachea, it passes into two large tubes called
bronchi that carry air into our lungs and then into smaller and smaller
branches called bronchioles. The bronchioles lead to tiny air sacs, the
alveoli, which transfer oxygen to the blood and remove carbon dioxide that
makes the same return trip when we breath out. Here, there is even a 4th line
of defense, the alveolar macrophages. These scavenger cells eat foreign
particles and bacteria that would make us sick.
HOW DOES POLLUTED AIR CHANGE THINGS?
hen we breathe polluted, smoggy air, tiny toxic air particles sneak past
the natural filters in our nose. Smog irritates the trachea making it hard to
breathe in and out. In the bronchi and bronchioles, air pollution can paralyze
or even destroy the cilia cells, which allows dirt and germs to build up in the
mucus and leaves the lungs defenseless against infections. Ozone kills the
alveolar macrophages that eat up foreign particles and bacteria. Smog also
damages the alveoli so they can't transfer oxygen as well as they should. All
of this can strain our heart, our lungs, our whole body. Breathing months and
years of smoggy air may cause premature aging of the lungs and make us
susceptible to infection, heart disease, and even cancer.
Next - The Nitty Gritty on 6 Harmful Pollutants...
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