Tuesday, April 30, 2019

Breath Tech

The Halimeter measures volatile sulfur compounds in the breath down to the parts per billion, and is used to identify the origin of one's bad breath.

It is a common factoid that body odors, particularly our breath, can be used to detect disease. Diabetes is a good example; it smells like acetone (nail polish), which is a result of the metabolism of excess ketones in the blood, which themselves are a result of the burning of fat instead of sugar, a solution the body uses when it has run out of sugar.

The holy grail of disease detection via the breath would be to identify cancer, and early enough that it can be stopped or reversed.

That's exactly what the Breath Biopsy study intends to develop. A large group of people will be chosen to breathe into a sampling vessel, from which their breath will then be sniffed, i.e., scanned for identifiable patterns, and saved for future reference.

Image source
Those people will be tracked into the future. For those who go on to develop cancer, their breath samples will be compared to those who did not develop the disease. The researchers are ultimately trying to find out how far in advance they can detect the cancer breath. This breathalyzer could then become a non-invasive way to identify the disease.

This painting by visionary artist Alex Grey isn’t about breath but about language. Nonetheless I thought it would look good here.

Jan 2019, CNN

Post Script:
I will repeat again here a story I find fascinating in regards to identifying disease by smell. I certainly cannot tell you that it's true; it's only meant to enliven discussion:

Although it does not happen often, it does happen that large plots of land previously used as a burial ground must get moved. On one of these occasions, after many days of work, the gravediggers (or whatever is the opposite of a gravedigger) reported markedly different smells coming from the many areas of the cemetery. After looking into it, the different odor-areas could be correlated to disease epidemics in history. Dirt that had been home for a hundred years to those who died during the diphtheria outbreak smelled different than that for tuberculosis.

Thursday, April 11, 2019

The City with No Smells

We all know that air pollution is a real threat, both to ourselves and our planet. And we all know that automobiles and electricity generated by fossil fuels are the major contributors to this pollution, and mostly because they are visible (except that they’re really not visible – the plumes you see exhausting from tailpipes and smokestacks tend to be water vapor; the polluting parts are invisibly microscopic.)

But there's another suspect out there which goes largely ignored, and as it would, because it's largely invisible to us.

We're not talking about cow farts, but cooking grease. To be more scientific, it is called organic aerosols, and it comes from the oils and organic matter that are heated in the process of cooking, and ejected out of the kitchen and into our urban environments.

As science starts to zero-in on atmospheric offenders, the local sources of pollution become more apparent. You will be way more exposed to the particulate matter exhausting from a tailpipe if you're driving right behind one, as opposed to watching it from your apartment window. But you are also more exposed to the organic aerosols exhausted from your local taqueria as you walk around your neighborhood, as compared to a pollution meter stationed on the roof of your 4-story apartment building.

So although global pollution is a problem for sure, local pollution is a problem even moreso, and one that needs to be managed in order to raise the quality of life for ever-increasing urban populations.

Thing is, although organic aerosols may be invisible, they are smellable. And although there are plenty of examples of restaurants "polluting" our urban environment with rancid reminders of why Yelp is still in business, there are just as many examples of locale-defining odor profiles marking your travels about your home neighborhood, or your favorite tourist destination.

Popcorn at the movie theater* is an obvious example, but there are plenty more of these olfactory advertisements to enjoy, and which even help to define a neighborhood. It's interesting to think of a historic preservation society that adds to their list of cornices and cobblestones a particular plume that really defines a place – a specific combination of cultural cuisine that can only be found in that little nook where the Polish krautmakers and Indian currystirrers all live together.

That being said, it’s not hard to imagine a future where everything that smells is bad for you and hence ridden. A city with no smells. Very healthy, very uninspiring.

*I was recently informed by a friend that, to him, "popcorn smells like vomit," which does make sense IF the butter is rancid, because isovaleric acid is a primary constituent of rancid butter, and is the smell of vomit and fermented feet sweat.

Nov 2018, phys.org

Post Script:
Good smells aside, when you roast things like nuts, popcorn or coffee, some of the compounds released are called diacetyls, which can cause serious respiratory problems for workers exposed to it in high amount.