The Human Pollution Experiment …

Can we design an experiment that shows us what happens to the lining of the nose when chronically exposed to pollution?

Why Not?

Normally it would be difficult to conduct an experiment to examine the effects of chronic exposure to air pollution on the nasal and sinus lining in children.

Imagine being the parent who is contacted by that researcher:

“… OK then, Mr. and Mrs. Smith, we’ll put your little Sally in this box for 6 months, and pipe industrial waste smoke into the box to see how that affects her nose and lungs and stuff.  Oh, and we’ll need to take little surgical biopsies occasionally.  You’re cool with that, right?  Just sign here …”

Not surprising, then, that there are not many such studies published in the medical literature.
Here is what we DO know:


Most of the information that we do have available is based on studies conducted in animals such as rats.  But what if there were a place that was so polluted, where the air quality was so fouled by industrial effluent, that it provided a natural polluted laboratory of sorts, for humans?

Physician-scientists would be able simply to examine the noses (and other organs for that matter) of children growing up in that environment, without purposely subjecting them to some inhumane experiments (we will save the debate over the inhumanity of over-crowding and pollution of our planet for another post).

If only humans lived in places that were so polluted that we didn’t need to actually design an experiment to answer the question …


Sadly, such places do exist on our planet – Bombay (Mumbai), Delhi, Mexico City, and many industrial cities in China, all come to mind (for list of top 10 most-polluted cities in the world, see resources below).  That picture above – that’s Delhi, India, one of those cities.

So – has anyone examined the noses and sinuses of children living in these places to determine the effects of their toxic environments?

There is one such study in the medical literature, and the findings are sobering:

Remember how the lining of the airways is made up of ciliated respiratory epithelium, with a few interspersed goblet cells to provide the mucus?  Well, the nasal epithelium of children growing up in a polluted environment shows severe structural changes including:

  • abnormal ciliated respiratory cells
  • abnormal cilia ultrastructure (at a molecular level)
  • abnormal goblet cells – the ones that make the secretions (snot)
  • cells found in a variety of stages of maturity (suggesting that the lining is producing more baby cells in an attempt to heal and repair the injury), and
  • an “inflammatory infiltrate” of lymphocytes throughout the lining

All of the changes on this list are signs of chronic inflammation.

Hull Breach

Respiratory Epithelium: Nasal and Sinus

In addition, signs of fluid leakage between the epithelial cells suggest that the cells are unable to maintain a tight seal, allowing fluids to leak out between them, but also – and this is important – this also allows microorganisms to slip in between the cells, headed in the other direction.

Like a breach in the hull of our spaceship, bad stuff gets in.

When your nose is exposed to pollution, the ‘tight junctions” were no longer tight.  Aliens (bacteria, viruses, molds, and particulate pollutants) are gaining entry to your system.  That means the nasal lining no longer keep out the bugs that want to get in and infect you!  Hull Breach.

The Cilia Don’t Work

Finally, the authors suggested that based on the abnormalities that they observed in the cilia, the cilia were unlikely to move normally.  Loss of mucociliary clearance.

That is, chronic exposure to polluted air results in acquired ciliary dysfunction, or acquired ciliopathy.  This means that these cells cannot do their job to sweep out mucus and particles that we breathe in.  As a result, the bad stuff stays around longer, making it more likely to gain access to your system.

Children Are Super Sensitive – Why?

One of the reasons that children are so susceptible to the hazardous effects of these toxins is that, per weight, they have higher metabolism, and breathe more air than an adult.  Children breathe, on average, twice as many breaths in a day than we adults do – about 40,000 breaths per day compared to our 20,000 per day.

In Summary

The authors suggested that the nasal lining of these children was

“… fundamentally disordered and that their nasal mucociliary defense mechanisms no longer function optimally.”

The authors concluded:

“Chronic exposures to air pollutants pose significant public health concerns for healthy individuals as well as those at higher risk, such as asthmatics and patients with compromised cardiorespiratory function. A compromised nasal epithelium has a diminished ability to protect itself and the lower respiratory tract.”

What To Do With This Information?

When these things happen – the stuff described above – respiratory illness worsens.

Infections, asthma, rhinitis, sinusitis.  So …

Treat your nose, and the noses of your children, with great care.

Minimize exposure to polluted air, whether from second hand smoke or smog.


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Of course, we are ALL exposed to allergens, viruses, bacteria, mold, and particulate pollutants, in the air we breathe in.  The solution is simply to rinse these away – see previous 4-part series on this blog on doing saline nasal rinses.  This is the way to take great care of your nose.

In turn, your nose will optimally do what it was designed to do – condition the air you breathe in, warm or cool it, humidify it, and filter out microorganisms and pollutants.

And if you’re fortunate, it will look nice too.

For the curious geeks (like me) out there, here is more about nasal and sinus anatomy and histology, some general principles that you can follow to keep your child’s nose and sinuses healthy.

Thanks for visiting, and see you here again.  I appreciate your comments and questions.  Keep ‘em coming.  Please, “be excellent to one another.”

Best of health and success to you and your families.

Until next time, remember … you can pick your friends, and you can pick your nose, but you can’t pick your friend’s nose (unless you’re a boogor doctor :~D)

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I promise to continue to work hard to help empower you with knowledge: to improve your health and the health of your children. RF


Lilian Calderón-Garcidueñas, Gildardo Valencia-Salazar, Antonio Rodríguez-Alcaraz, Todd M. Gambling, Raquel García, Norma Osnaya, Anna Villarreal-Calderón, Robert B. Devlin, and Johnny L. Carson:  Ultrastructural Nasal Pathology in Children Chronically and Sequentially Exposed to Air PollutantsAmerican Journal of Respiratory Cell & Molecular Biology.  24: 132-128; 2001.

Pedersen M: Ciliary Activity and PollutionLung.  168:  368-376; 1990.

Top 10 most-polluted cities in the world, 2010:


  1. physician assistant says:

    Great information! I’ve been looking for something like this for a while now. Thanks!

  2. Thanks for a easy to understand explanation of effects of pollutants. My husband works as a refueller at a major Australian airport and often breathes in jet exhaust on the Tarmac. He has has had many sinus infections that clear up but has just has had an awful sinus and ear infection. I now believe 13 years of this work may be taking its toll on his respiratory system. I’m going to take him to an ENT specialist! Again ,thank you.

    • Russell A. Faust, PhD, MD says:

      Hi Louise,

      You are very welcome. I am personally very sensitive to diesel and other exhaust fumes because of the particulate irritants. Regular nasal saline rinses can help. Be sure to check out for more information – Dr. Hana’s site is a great resource!

  3. Gary Donnelly says:

    You forgot to mention N.Y.C. and its surrounding areas, as a pollution threat.

    • Russell A. Faust, PhD, MD says:

      Agreed! But, sad to say that, on a global comparison, NYC isn’t even in the running. Sad for the others, that is!

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