Speaker 1: Welcome to Stuff to Blow Your Mind, a production of iHeartRadio.
Speaker 2: Hey, welcome to Stuff to Blow Your Mind.
Speaker 3: My name is Robert Land, and I am Joe McCormick,
Speaker 3: and today we're going to be kicking off a series
Speaker 3: about the topic of dust. I came to this one
Speaker 3: along a quite literal route. I was recently cleaning out
Speaker 3: some boxes that I had stored in a closet for years,
Speaker 3: and in the process stirred up a bunch of dust
Speaker 3: and then I just sat there breathing it while I
Speaker 3: was going through all my old stuff trying to figure
Speaker 3: out what to get rid of and all that. And
Speaker 3: this process greatly irritated my airways. But through the irritation,
Speaker 3: I ended up thinking a lot about dust and about
Speaker 3: what dust means to us. So we're surrounded by dust
Speaker 3: all the time. You know, it's in all of our homes,
Speaker 3: and it's a major concern of simple cleanliness and hygiene
Speaker 3: in the house. But it's also of huge significance to
Speaker 3: the natural environment, to cycles of weather and water, and
Speaker 3: it is of great significance to our health. Dust has
Speaker 3: so much influence on our lives. And yet it's interesting
Speaker 3: that when you think about the way dust imagery is
Speaker 3: used in like, you know, metaphors and poetry and mythology
Speaker 3: and all that. It seems to me that what dust
Speaker 3: is most often used to symbolize is uselessness, worthlessness, meaninglessness,
Speaker 3: things of no lasting significance.
Speaker 2: Yeah, I was. I picked up a Brewer's Dictionary of
Speaker 2: Phrase and fable, just looking up dust and seeing what
Speaker 2: kind of like maybe old antiquated terminology and sayings might
Speaker 2: be invoked there. And sure enough there was one for
Speaker 2: referring to money as dust, which I had not run
Speaker 2: across before. Like the idea of being like it's money,
Speaker 2: it's ultimately worthless, and therefore you call it dust.
Speaker 3: Vocabulary in that way is like a talisman against the
Speaker 3: power of money.
Speaker 2: Yeah.
Speaker 3: Yeah. Examples of this kind of usage of dust meaning
Speaker 3: that which is worthless, meaningless, you know, of no lasting significance.
Speaker 3: These go back to ancient myths and religious literature. But
Speaker 3: one of the most famous examples that came to my
Speaker 3: mind is in Shakespeare's Hamlet. It's the Quintessence of Dust
Speaker 3: monologue in Act Too Seen To where Hamlet is talking
Speaker 3: to Rosencrantz and Guildenstern, and he says famously what a
Speaker 3: piece of work is a man? How noble in reason,
Speaker 3: how infinite in faculty, in form and moving, how express
Speaker 3: and admirable in action, How like an angel in apprehension,
Speaker 3: how like a god? The beauty of the world, the
Speaker 3: paragon of animals? And yet to me, what is this
Speaker 3: quintessence of dust? So the final thought there is kind
Speaker 3: of the negation of everything he said beforehand, all of
Speaker 3: the amazing powers of humankind or beauty, or the way
Speaker 3: in which we are made in the image of God.
Speaker 3: According to Hamlet, ultimately mankind is as worthless and meaningless
Speaker 3: as the dust from which it was made. And this
Speaker 3: betrays a kind of running theme of obsession with physical death,
Speaker 3: which sort of neutralizes all meaning and renders everything pointless.
Speaker 3: I guess when Hamlet is in his depressive moods.
Speaker 2: Yeah, I mean, there's of course the line in the Bible,
Speaker 2: the King James version being for dust thou art, and
Speaker 2: unto dust, thou shalt thou return, which you know, is
Speaker 2: pretty on point, but I think it also misses all
Speaker 2: of the dust in between, because it will be discussing
Speaker 2: like dust is just so ubiquitous. It's not just like
Speaker 2: that thing at the beginning of the end, like it's
Speaker 2: everywhere in between two, Like it's in the living body,
Speaker 2: it's brought into the living body, it's in the living world,
Speaker 2: and it's out there in the cosmos.
Speaker 3: Oh yeah, well that's kind of a beautiful observation. I
Speaker 3: like that counterpoint that, of course life in many ways
Speaker 3: is dust. There is a dust of life in the
Speaker 3: same way that there is a dust of death. But
Speaker 3: I also still think that it's intriguing and curious that
Speaker 3: there's so much literature and poetry and stuff where the
Speaker 3: image of dust seems to emphasize almost cosmic horror, you know,
Speaker 3: the great vast emptiness and negation of all of life's
Speaker 3: grandiose illusions of worth, Like why is that? What is
Speaker 3: it about if you look at a pile of dust?
Speaker 3: What is it about a pile of fine, granular particles
Speaker 3: of matter that takes on such a powerfully depressing symbolic heft.
Speaker 2: Yeah, fear and a handful of dust.
Speaker 3: Right, So, I guess a good place to start for
Speaker 3: the series is to tackle the question quite literally, what
Speaker 3: is dust in a physical sense? And I found that
Speaker 3: in scientific usage, the stuff that we call dust is
Speaker 3: often broken down with more specific terminology depending on the field.
Speaker 3: But I did find a book actually that gave what
Speaker 3: I thought was a really good definition of dust generally.
Speaker 3: So I came across this because I was reading an
Speaker 3: interview in Wired magazine with an author named Jay Owens.
Speaker 3: She's the author of a twenty twenty three book called
Speaker 3: Dust The Modern World in a Trillion Particles, and I
Speaker 3: like the author's thoughts, so I ended up buying the
Speaker 3: book to explore the topic more. And by the way,
Speaker 3: this book isn't purely about like the science of dust.
Speaker 3: It delves into politics and religion and philosophy and so forth.
Speaker 3: But in terms of a physical definition, the definition of
Speaker 3: dust the author uses is tiny flying particles. This is
Speaker 3: sort of a compromise that works across multiple domains, and personally,
Speaker 3: I think it works quite well because it captures the
Speaker 3: three main properties common to all the things we call dust,
Speaker 3: so tiny flying particles. First, we look at particles, meaning
Speaker 3: pieces of solid matter. In the atmospheric sciences, people often
Speaker 3: talk about the idea of aerosols, meaning particles or droplets
Speaker 3: that are suspended in the air, like suspended within a gas.
Speaker 3: But this includes things that obviously aren't what people mean
Speaker 3: by dust, such as floating liquid droplets like mist or fog,
Speaker 3: and many types of air pollution contain a mix of
Speaker 3: liquids and solid particulates. But in common usage, I think
Speaker 3: dust means a substance made mostly of solid particles. Right.
Speaker 3: Second element of tiny flying particles we can look at tiny.
Speaker 3: There is no universally agreed upon size for dust particles,
Speaker 3: but based on reading Owens and other sources, it seems
Speaker 3: that what we call dust is always made of particles
Speaker 3: less than a millimeter in diameter, and usually on a
Speaker 3: scale of one hundred to one thousand times smaller than
Speaker 3: a millimeter, which means between one and ten micrometers or
Speaker 3: microns in size. So again, a micrometer is one one
Speaker 3: thousandth of a millimeter. And for comparison, Owen's notes that
Speaker 3: human hair is on average somewhere between seventy and ninety
Speaker 3: micrometers in width. So if I did the math on this, right,
Speaker 3: what we call dust is usually somewhere between one percent
Speaker 3: to about fifteen percent the width of a human hair.
Speaker 2: Right, So very often the particles of dust we're talking about,
Speaker 2: they're not even really visible to the human eye. Though
Speaker 2: again you're going to have some particles that are larger than.
Speaker 3: Others exactly, and they're things that are often not visible
Speaker 3: on their own but are visible in aggregate.
Speaker 2: Right. So like when you walk in and you decide
Speaker 2: to sit down at your hobby table, I don't know,
Speaker 2: your typewriter, whatever air of your house is beloved but
Speaker 2: perhaps neglected, and you say, who put all this dust here?
Speaker 2: You know you I can think of it in terms
Speaker 2: of who put all of these dust particles here on
Speaker 2: my hobby table? You know it's you see it again
Speaker 2: in aggregate, like you said, and how did they get there? Well,
Speaker 2: that goes right into your next point, right, So.
Speaker 3: The third part of Owen's definition tiny flying particles is flying.
Speaker 3: So a core element of dust is that dust particles
Speaker 3: can easily be stirred up by airflow and other types
Speaker 3: of physical agitation, and then they float in the atmosphere
Speaker 3: for a significant time before settling down. So you might
Speaker 3: think of, say, grains of sand on the beach as
Speaker 3: tiny particles, but a lot of those grains are large
Speaker 3: enough that if you grab a fistful of sand off
Speaker 3: of beach and you throw it up in the air,
Speaker 3: those grains of sand will plummet straight back down to
Speaker 3: the ground. However, some of the mass of that fistful
Speaker 3: of sand will probably be made up of dust sized
Speaker 3: particles which will remain in the air as a cloud
Speaker 3: for some time, while the larger grains just fall to
Speaker 3: the earth. So a characteristic feature of dust is its
Speaker 3: ability to float in the air but also to travel
Speaker 3: on the air. So this made me think about how
Speaker 3: when you see a surface in your house, so maybe
Speaker 3: a bookshelf in dust, you don't look directly above it
Speaker 3: to see where the dust was falling from. Maybe you
Speaker 3: do if you see larger pieces of something on top
Speaker 3: of it. But if it's just dust, we understand that
Speaker 3: dust migrates on currents of air and it settles somewhere
Speaker 3: potentially very far from its origin. So it doesn't just fall,
Speaker 3: but it travels. So that's the rundown of Owen's definition,
Speaker 3: and I think it's a good one. Dust is made
Speaker 3: of tiny flying particles. But there's another sense of the
Speaker 3: question what is dust? And that sense is what is
Speaker 3: it made of? And this is another interesting point that
Speaker 3: Owen's race is. In the introduction of her book, she
Speaker 3: argues that dust is also defined by quote A certain
Speaker 3: loss of context, an inherent formlessness. And that might sound
Speaker 3: maybe overly poetic, but I think that's actually a quite
Speaker 3: good specific point. It's the fact that dust is made
Speaker 3: of many different substances and we don't know what they are,
Speaker 3: and that is what makes it dust. Because if we
Speaker 3: did know exactly what it was made of, and we
Speaker 3: saw it, say, pouring in fine floating grains from its
Speaker 3: original source, we probably wouldn't call it dust. We would
Speaker 3: call it whatever it was. We might say, look, that
Speaker 3: is oak pollen, or that is pet dand or floating
Speaker 3: off of my dog, or that is silica powder coming
Speaker 3: out of a container, or it's you know, concrete dust
Speaker 3: coming up off of a concrete being mixed in a bucket.
Speaker 3: It is the loss of its original context and the
Speaker 3: mixing together with other such substances lost from their original context,
Speaker 3: to that blending together that makes these unknown particles simply dust.
Speaker 2: Yeah, it's only in the Hollywood context that you have
Speaker 2: a definite source of dust. I was looking around at
Speaker 2: some of these gadgets earlier. You can pick up like
Speaker 2: a handcrake dust gun for pretty cheap, and then you
Speaker 2: have you know, far more advanced models as well. Where
Speaker 2: you would actually have the dust particles inside of a
Speaker 2: reservoir and then you are spraying them out onto a surface.
Speaker 2: So you know, you can get that like nice haunted
Speaker 2: manner layer of dust so that your lead actor can
Speaker 2: come in, you know, perhaps drag their finger over the
Speaker 2: surface of a piano and then look around at the
Speaker 2: haunted surroundings. But then you have to do another take
Speaker 2: and spend several minutes like removing all the dust and
Speaker 2: then apply reapplying the dust. I've heard accounts of that
Speaker 2: sort of thing in movie production before.
Speaker 3: Now, what about when the actor who's like been through
Speaker 3: a lot, like you know, they're coming in out of
Speaker 3: the desert or something and they pat themselves and the
Speaker 3: dust comes off of them in a cloud. I wonder
Speaker 3: do they have to get redusted again each take?
Speaker 2: I bet so. I mean there's all sorts of I mean,
Speaker 2: it's kind of the reverse of the whole like having
Speaker 2: to polish Darth Vader's helmet, you know, constantly to make
Speaker 2: sure sure that you're not getting any smudges on there
Speaker 2: or anything. But yeah, you're interested in the cinematic dusting. Yeah,
Speaker 2: you can go to various websites and you can look
Speaker 2: up the movie dust. You can buy it in various sizes,
Speaker 2: various instruments to to spray the movie dust around.
Speaker 4: It's kind of fun, okay.
Speaker 3: So dust is the name for tiny flying particles from
Speaker 3: an unknown source. But when we actually get in there
Speaker 3: with the microscope and the lab equipment, we of course
Speaker 3: can study dust and figure out where it comes from
Speaker 3: and what it's made of. So what is dust most
Speaker 3: often made of when we encounter it? Of course, it
Speaker 3: depends where you're taking the sample from. Worldwide, Owen says
Speaker 3: the most prevalent type of dust is mineral in origin,
Speaker 3: so tiny grains of rock broken apart by natural processes
Speaker 3: or worn down by erosion, and you know they come
Speaker 3: from the rocks, the rock layers of earth, and these
Speaker 3: minerals are born aloft by winds and other primarily by winds,
Speaker 3: but by whatever source agitates them. Inside a home, a
Speaker 3: lot of the dust you will find still does come
Speaker 3: from soil tracked in or blown in from the outside,
Speaker 3: but there are also non soil particles carried in from outside,
Speaker 3: including pollen and particulates in the air that come from combustion,
Speaker 3: such as soot. Soot can be a big constituent of dust.
Speaker 3: Also soot from any combustion happening inside the house. Cooking
Speaker 3: in the house is a large source of particles inside
Speaker 3: the air of a home. But also there are, I
Speaker 3: don't know, depending on your point of view, perhaps grosser
Speaker 3: sources of dust, but hair from humans and pets, dead
Speaker 3: skin cells from humans, as well as pet dander, you know,
Speaker 3: stuff coming off of the skin of pets. There are
Speaker 3: fibers from inorganic sources in the home, fibers from carpets, furniture,
Speaker 3: and clothing, other organic particles like pieces of dead insects,
Speaker 3: wonderful little cockroach crumbs all over the house. And then
Speaker 3: just you know, random stuff, tiny bits of random garbage
Speaker 3: like pieces of paper, waste, and plastic.
Speaker 2: This episode is brought to you by dusting. Have you
Speaker 2: dusted today? Don't you want to? Now?
Speaker 3: Oh, let me give you another reason, because among all that,
Speaker 3: there is something else, some part of the dust itself
Speaker 3: which is alive and feeding and growing and living amongst
Speaker 3: us always, and that is dust mites. I got really
Speaker 3: interested in dust mites for this episode, so I wanted
Speaker 3: to do a little sidebar here on dust mites. So
Speaker 3: there are many types of mites. House dust mites are
Speaker 3: one particular branch of them, belonging to the family pyro glyffidy.
Speaker 3: And I was trying to parse the name. That name
Speaker 3: through its Greek roots pyro is fire and glyphid would
Speaker 3: seem to mean like carving. But then I found a
Speaker 3: source saying exactly what it means. And the name of
Speaker 3: the pyroglyphid mites comes from the fact that these dust
Speaker 3: mites can cause irritation on the skin, rashes and irritation
Speaker 3: on human skin, like burns from fires, like fire carvings
Speaker 3: on the skin. So house dust mites are microscopic bugs
Speaker 3: that can be found all throughout human dwellings. They are
Speaker 3: They're not insects. Instead, they are eight legged arachnids, more
Speaker 3: closely related to spiders than to insects. They are microscopic
Speaker 3: and can possibly be seen without the aid of a microscope,
Speaker 3: but would rarely be noticed without visual magnification. Their body
Speaker 3: lengths are on the order of a few hundred micrometers.
Speaker 3: So these dust mites are in many human homes, living
Speaker 3: all around us. How do these dust mites make a living?
Speaker 3: What are they doing in our homes? You might be
Speaker 3: able to guess that by knowing the genus name of
Speaker 3: a couple of the most common varieties of house dustmites.
Speaker 3: That genus name is Dermatophagoides skin eaters. They are skin
Speaker 3: eaters generally dead skin that is already flaked off of
Speaker 3: your body, so fortunately you know, usually they can they
Speaker 3: can find something that's not still attached to you.
Speaker 2: Polite skin eaters they.
Speaker 3: Hunt for these discarded rafts of mammal skin in the
Speaker 3: microforests of our homes, in carpets, mattresses, in the soft
Speaker 3: weave of furniture. But despite their tiny size and the
Speaker 3: fact that they're usually looking for stuff that has already
Speaker 3: fallen off of you, house duestomites and their feces are
Speaker 3: a major problem for humans. They are a major source
Speaker 3: of allergens within the home. In fact, according to one
Speaker 3: paper that I'm going to get to in just a second,
Speaker 3: pyroglyphid mites are the single greatest source of allergic symptoms
Speaker 3: in human beings.
Speaker 2: Total.
Speaker 3: The authors of the paper estimate that they cause allergies
Speaker 3: in somewhere between sixty five million and one point two
Speaker 3: billion people.
Speaker 2: This episode is also brought to you by washing your sheets.
Speaker 2: Have you washed your sheets lately, don't you want to?
Speaker 3: Now, I want to clarify that these are these are
Speaker 3: different than bedbugs, by the way, Yes, yeah, dust mites.
Speaker 3: I mean they'll they'll find them all over the place.
Speaker 3: They're not the same as bedbugs. You know, bed bugs
Speaker 3: are looking for a blood meal. The dustimites are looking
Speaker 3: for the skin flakes. Now here's maybe a good point
Speaker 3: to describe what they look like, Rob. I've attached some
Speaker 3: pictures of dustimites for you. These are several micrographs of pyroglyphids.
Speaker 3: So what do you see here?
Speaker 2: I mean they basically look like the head crabs from
Speaker 2: the old Half Live video games.
Speaker 3: That's perfect, That's exactly it. Yeah, one of these. So
Speaker 3: some of these are like scanning electron micrographs. I guess that.
Speaker 3: You know, they're a lot of texture. It's false color,
Speaker 3: I guess. But in the one shown from right above,
Speaker 3: I mean they've got a bit of a spidery appearance
Speaker 3: because they have eight legs and these you know, the
Speaker 3: these mouth parts up in the front, the kind of
Speaker 3: finger fangs sort of. But also one of these big
Speaker 3: pictures we have to look at, the skin just looks
Speaker 3: kind of like wrinkly and deflated. It's like a half
Speaker 3: inflated basketball.
Speaker 2: Yeah yeah. I'd also like how the wrinkle on this
Speaker 2: particular image looks kind of like a mouth, So it
Speaker 2: kind of looks like some sort of a whiskery Muppet creature,
Speaker 2: like from like a nineties Muppet creature, not a classic Muppet.
Speaker 3: Oh, it looks exactly like either the Nightmare Before Christmas,
Speaker 3: the Oogie Boogieman, or looks like the sorting hat from
Speaker 3: the Harry Potter movies.
Speaker 2: Yeah.
Speaker 3: Yeah. The really magnified images I have for you are
Speaker 3: the the false color images, but the ones in true
Speaker 3: color you can see that they're generally kind of white
Speaker 3: in appearance. Again, they're very very small, so hard to
Speaker 3: see with the naked eye, but kind of white and
Speaker 3: a little bit grub like in appearance, with the limbs
Speaker 3: coming out in the front in a larger sort of
Speaker 3: white bulb of a body extending behind. Now, I wanted
Speaker 3: to come back and take a brief look at a
Speaker 3: dust mite paper that I just brought up a minute ago.
Speaker 3: This is a paper called is Permanent Parasitism Reversible Critical
Speaker 3: Evidence from early evolution of house dust mites. This is
Speaker 3: by Pavel B. Klimov and Barry O'Connor published in Systematic
Speaker 3: Biology in twenty thirteen, and there are a couple of
Speaker 3: things I wanted to talk about here. First is just
Speaker 3: a passage directly about the allergenic quality of these mites,
Speaker 3: about why the feces of pyroglyphid mites are so prone
Speaker 3: to cause irritation and allergic reaction in humans the author's
Speaker 3: right quote. Dust mites feed on organic debris such as
Speaker 3: shed skin and flourish in nests of vertebrates, including human dwellings.
Speaker 3: The mites severe allergenic properties are linked to their powerful
Speaker 3: digestive and molting enzymes, salivary secretions, and other water soluble molecules.
Speaker 3: For example, large quantities of digestive enzymes accumulate in mite's
Speaker 3: fecal material, minute particles that can easily become airborne when
Speaker 3: inhaled or in contact with skin. The residual mite enzymes
Speaker 3: may break up tight junctions between epithelial cells and trigger
Speaker 3: allergic reactions. So these mites they make tiny poops, and
Speaker 3: their tiny poops are full of the digestive enzymes that
Speaker 3: they use to break down their food, and their food
Speaker 3: is human skin flakes and in the broader context, things
Speaker 3: that contain keratin, like of course skin cells, but also
Speaker 3: like bird feathers, which these animals also eat. So it
Speaker 3: is like they have evolved a digestive enzyme that makes
Speaker 3: it possible for them to eat difficult to digest things
Speaker 3: that fall off of us and get nutrition out of that.
Speaker 3: And then they poop, and their poop contains the enzymes
Speaker 3: that allow them to break that stuff down. And then
Speaker 3: that poop gets stirred up in the air and becomes
Speaker 3: part of the dust in our homes and gets on
Speaker 3: people's skin and in their airways and so forth. But anyway,
Speaker 3: to come to a bigger picture issue, the real point
Speaker 3: of this paper is related to the evolutionary history of
Speaker 3: the house dust might how did these microscopic animals end
Speaker 3: up living this way, crawling through the jungles of the
Speaker 3: couch cushions, you know, getting into the area rug to
Speaker 3: munch on our dead skin flakes. How did they end
Speaker 3: up that way? Well, the authors of this paper used
Speaker 3: genomic evidence cross comparing different lineages of mites of these
Speaker 3: pyroglyphids and related organisms to show that these free living
Speaker 3: mites within our homes. It used to be even closer
Speaker 3: companions than they are now. They evolved from fully obligate
Speaker 3: permanent parasites of warm blooded vertebrates like birds and mammals
Speaker 3: the author's right quote. We propose that parasitic ancestors of
Speaker 3: pyroglyphids shifted to nests of vertebrates. Later, the nest inhabiting
Speaker 3: pyroglyphids expanded into human dwellings to become a major source
Speaker 3: of allergens. So these evolved from creatures that were once
Speaker 3: free living organisms and then evolved a tight specialized parasite
Speaker 3: relationship with warm blooded vertebrates like mammals and birds and
Speaker 3: would live directly on the host, and then shifted away
Speaker 3: from that tight specific parasitic relationship to be to have
Speaker 3: a more loose relationship, to be free living into somewhat,
Speaker 3: you know, to sort of scavenge what falls off of
Speaker 3: the host animal or the former host animal. And that's
Speaker 3: interesting because this kind of despecialization from a tight parasite
Speaker 3: host relationship to a more generalized free living dust no
Speaker 3: mad lifestyle was considered quite unusual, something that is rarely
Speaker 3: observed in evolution, and at some times in the past
Speaker 3: was thought impossible. But it's clearly not impossible. It's just
Speaker 3: evolutionarily difficult to do to get out of that sort
Speaker 3: of tight, tight adaptive dead end where you are stuck
Speaker 3: in a relationship with this host animal to become a
Speaker 3: little more of a generalist and get a little bit
Speaker 3: more distance and still be able to survive.
Speaker 2: What's like, it's almost like evolutionarily they survive the passage
Speaker 2: to the promised land, the promised land being the augmented
Speaker 2: environment that is the human home.
Speaker 3: Oh that's interesting. Yeah, I mean they have to they
Speaker 3: still have to be very specialized to survive within the
Speaker 3: human home. They have to be able to tolerate different
Speaker 3: kinds of environmental conditions than they would if they were
Speaker 3: living directly on the on the mammal or the bird body. Like,
Speaker 3: they have to be able to tolerate less reliability. And
Speaker 3: I think I think one of the things is they
Speaker 3: have to be more resistant to dehydration, you know, because
Speaker 3: like it's harder to get water when you're just living
Speaker 3: in the dust.
Speaker 2: Uh.
Speaker 3: They have to have these digestive enzymes that allow them
Speaker 3: to break down difficult foods like the keratin and skin
Speaker 3: skin cells and stuff like that. But apparently they got
Speaker 3: all the right adaptations, and now they're here. Now they're
Speaker 3: living in the in the couch cushion.
Speaker 2: Yeah, it's my understanding that humidity is key. You look
Speaker 2: around and you see various advice about dust mites in
Speaker 2: the home, and like some some people advise having a dehumidifier,
Speaker 2: for example, trying things out a bit, and then on
Speaker 2: top of that, of course washing sheets and so forth
Speaker 2: to appropriate temperatures, and some people advocate like putting I
Speaker 2: guess in cases where you don't have time to do
Speaker 2: this and you're dealing perhaps with you know, some sort
Speaker 2: of a more severe allergy to them, putting bedding in
Speaker 2: the freezer for a certain amount of time and then
Speaker 2: removing them.
Speaker 3: Oh interesting, I guess that would really dry it out.
Speaker 2: Yeah, and then I guess then you've got both sides
Speaker 2: of the pillow or the cold side of the pillow,
Speaker 2: so wind win.
Speaker 3: Okay, that's all I've got on dust mites for now,
Speaker 3: but we may come back to them later in the
Speaker 3: series and.
Speaker 2: They may re emerge for sure. Now, for the rest
Speaker 2: of this episode, I wanted to talk a little bit
Speaker 2: more about atmospheric dust, which we've already touched on. We've
Speaker 2: talked about the ways that the dust is floating around.
Speaker 2: It's stirred up easily by just movement and through the
Speaker 2: atmosphere that we all live in, or of course by
Speaker 2: by weather patterns and so forth. We've talked about how
Speaker 2: you know, an individual particle of dust is often invisible
Speaker 2: to the naked eye, but in great volumes it's different.
Speaker 2: And that great volume may be the great volume of
Speaker 2: dust on your dining room table when after you come
Speaker 2: back from traveling, or it could indeed be the great
Speaker 2: volumes of dust seen in a dust devil or seen
Speaker 2: in a dust storm. Because again, dust is everywhere suspended
Speaker 2: in the air, It's steadily accumulating on surfaces, and we
Speaker 2: often don't notice it until it builds up to a
Speaker 2: certain threshold.
Speaker 3: This is why it never seems like you need to
Speaker 3: dust until it's already too dusty.
Speaker 2: Yeah, yeah, and at that point you realize you live
Speaker 2: in foul and you've got to fix things now. Atmospheric
Speaker 2: dust is important because, of course it impacts both human
Speaker 2: health and climate, though of course these two topics overlap. Dust,
Speaker 2: according to the NAA, is the single largest component of
Speaker 2: the aerosols in Earth's atmosphere. It likely has a huge
Speaker 2: impact on Earth's climate and affects everything from oceanic temperatures
Speaker 2: to snow melt rates. There also seems to be a
Speaker 2: connection between dust and hurricanes, with data points to an
Speaker 2: inverse relationship between dust in the North Atlantic tropics and
Speaker 2: various Atlantic hurricanes. I was looking at a few different
Speaker 2: sources on all of this. One in particular, there's a
Speaker 2: NAA article from twenty sixteen titled the Dirt on Atmospheric Dust,
Speaker 2: and that twenty sixteen stat is key because a little
Speaker 2: later I'm going to touch on some research that raises
Speaker 2: the question about like where we are in terms of
Speaker 2: our modeling of atmospheric dust and so forth. But based
Speaker 2: on this source, it says that we're looking at somewhere
Speaker 2: between two hundred and five thousand terograms of dust entering
Speaker 2: the atmosphere each year, with one teogram equaling one trillion grams.
Speaker 3: My kitchen scale does not go up to a terogram.
Speaker 2: There's also an estimated twenty terograms of dust suspended in
Speaker 2: the atmosphere at any given time, with seasonal variations. Now,
Speaker 2: the amount of time that an individual dust particle remains
Speaker 2: in the air that depends on particle size. Apparently, larger
Speaker 2: particles may remain suspended for no more than like twenty
Speaker 2: four hours, but much smaller particles, they can say, aloft
Speaker 2: much longer than the period of time that the NAA
Speaker 2: mentions in this article is twenty days or even more.
Speaker 2: Now another figure I ran across. This is from Robert
Speaker 2: Monroe's Increased atmospheric dust has masked power of greenhouse gases
Speaker 2: to warm planet from January twenty twenty three. This was
Speaker 2: published on the website of the Script's Institution of Ocean Oceanography,
Speaker 2: and it puts it like this quote, twenty six million
Speaker 2: tons of such particles globally equivalent to the weight of
Speaker 2: about five million African elephants floating in the sky.
Speaker 3: I came across some numbers within the same range offered
Speaker 3: in the introduction to Jay Owen's book. So in the
Speaker 3: Dust Book, she includes estimates that somewhere between and this
Speaker 3: is a big range, but no matter what, this is
Speaker 3: a huge number. Somewhere between eight and thirty six million
Speaker 3: metric tons of mineral dust are floating in the atmosphere
Speaker 3: at any given time, And I was trying to come
Speaker 3: up with a comparison for that number. Looking for figures
Speaker 3: in that range. One I found was kind of interesting,
Speaker 3: not that it's all that easy to picture this, but
Speaker 3: just as a conceptual comparison, I found a paper published
Speaker 3: in PNAS from twenty twenty three by Greenspoon. It all
Speaker 3: called the Global Biomass of Wild Animals, And so the
Speaker 3: authors of this paper were just estimating for certain categories
Speaker 3: of animals and organisms on Earth how much total biomass
Speaker 3: is there if you were to weigh them all at
Speaker 3: the same time. And the authors, based on their methodology,
Speaker 3: estimated that if you were to put together all of
Speaker 3: the wild land mammals on Earth, so all the mammals
Speaker 3: that are not domesticated live out in the wild on land,
Speaker 3: there would be about twenty two million metric tons worth,
Speaker 3: and a lot of those animals are going to be
Speaker 3: things like deer, wild pigs, elephants, and so forth. There
Speaker 3: would be about twenty two million metric tons worth. And
Speaker 3: by the way, that number is quite small compared to
Speaker 3: the total biomass of humans. There would be three hundred
Speaker 3: and ninety million metric tons of humans and six hundred
Speaker 3: and thirty million worth of domestic and city dwelling animals.
Speaker 3: But all of the wild land animals are about twenty
Speaker 3: two million metric tons, which is sort of in the
Speaker 3: middle of Owens's eight to thirty six million metric tons
Speaker 3: of dust range. So that's a lot of dust in
Speaker 3: the air. It's kind of hard to imagine.
Speaker 2: Yeah, yeah, And again part of it is because it
Speaker 2: is just mostly invisible to us, and even when it's visible,
Speaker 2: it's hard to think in terms of, oh, that dust devil,
Speaker 2: that dust cloud, even if you're looking at satellite Maybe
Speaker 2: when you're looking at satellite imagery you can sort of
Speaker 2: think in terms of millions and millions of elephants. Now,
Speaker 2: the next question you may ask in a number if
Speaker 2: you already know the answer to this, I'm sure, is
Speaker 2: where does the dust come from? On the whole, it
Speaker 2: comes from the deserts. So according to again the NOAA
Speaker 2: and twenty sixteen, more than half of the world's atmospheric
Speaker 2: dust originates in North Africa. This is the Saharan connection
Speaker 2: that you've probably heard of, with the greater Saharan desert
Speaker 2: dust transport across the Atlantic having been linked to things
Speaker 2: like El Nino and other weather phenomena. So that's like
Speaker 2: half the dust more or less based on these measurements
Speaker 2: and estimations and models. The rest is thought to originate
Speaker 2: from other major desert regions around the world that share
Speaker 2: the right characteristics.
Speaker 3: Well, what are those characteristics?
Speaker 2: All right? So these are areas that sit in low
Speaker 2: elevation basins near or surrounded by mountains, and the mountains
Speaker 2: are key because these feed rivers, which deposit vast amounts
Speaker 2: of sediment into low lying regions. So that makes these
Speaker 2: regions dust collecting and distribution engines for the atmosphere. Okay,
Speaker 2: now we should also point out that there are other
Speaker 2: major dust engines, certainly if you have wildfires we mentioned
Speaker 2: so earlier, but also volcanoes. Right when a volcano erupts,
Speaker 2: we've talked about this on the show before you know,
Speaker 2: injects injects of vast amounts of volcanic dust into the atmosphere,
Speaker 2: and these injections are often large enough to impact human
Speaker 2: health and human activity to varying degrees, and these are
Speaker 2: often visible from space.
Speaker 3: So we've seen how the creation of atmospheric dust in
Speaker 3: some way depends on the complex interactions of other cycles
Speaker 3: and processes on the surface of the Earth, like the
Speaker 3: interaction of the water cycle and of water coming down
Speaker 3: from mountains and mixing correctly with the with the desert environments,
Speaker 3: and then of course that being affected by wind which
Speaker 3: raises dust up into the air. So but it also
Speaker 3: works on the other end too, right, like dust in
Speaker 3: turn affects complicated processes all around the globe.
Speaker 2: That's right again. You think of like the various you know,
Speaker 2: convection and system of movement of air throughout our atmosphere,
Speaker 2: and just imagine dust getting caught up in all all
Speaker 2: of that, you know. So, yeah, atmospheric dust has a
Speaker 2: few properties worth stressing in relation to climate and weather. Here.
Speaker 2: On one hand, there's the role played by dust particles
Speaker 2: in the formulation of water droplets. So these form when
Speaker 2: water vapor shifts to liquid form around a condensation nucleus
Speaker 2: such as a particle of dust, and then these particles
Speaker 2: of dust with water condensing around it, these coalesce into clouds.
Speaker 2: And then all of these particles with water around these
Speaker 2: water droplets, they fallows rain, and this whole cycle continues.
Speaker 2: And if you've ever absorbed any material about how rain
Speaker 2: drops work and so forth, you've probably heard about this.
Speaker 3: So to some extent, dust quite literally makes it rain.
Speaker 2: Yeah, and then there's the fact that atmospheric dust can
Speaker 2: have both a apparently both a cooling and warming effect
Speaker 2: on the planet, and temperature of course plays a vital
Speaker 2: role in climate and weather as well. But the exact
Speaker 2: net effect of dust warming or cooling this seems to
Speaker 2: remain a complex topic of discussion. But one of the
Speaker 2: people that has been studying this as looking at stuff
Speaker 2: that this person has said and written and also articles
Speaker 2: about their work. This is Jasper Cock, a UCLA Assistant
Speaker 2: Professor of Atmospheric and Oceanic sciences, and according to Cock,
Speaker 2: here dust can have either a net cooling or net
Speaker 2: heating effect on the atmosphere, depending on the size of
Speaker 2: the particles. Ah okay, so in the cooling scenario in
Speaker 2: recent studies may point it seems and coxingstandicate this as
Speaker 2: well to a slight overall cooling effect. You have dust
Speaker 2: particles reflecting sunlight back into space and also dissipating high
Speaker 2: clouds that warm the planet. Now on the warming side
Speaker 2: of the whole scenario, dust landing on the surface of
Speaker 2: the planet again, it can coat your car, it can
Speaker 2: coat your dinner table, and so forth. But it also
Speaker 2: can coat snow and ice with dark particles that increases
Speaker 2: the absorption of heat.
Speaker 3: Ah Okay, that's right. So if it was just pure
Speaker 3: snow or ice, it would reflect more of the Sun's
Speaker 3: energy back out into space. But if you cover it
Speaker 3: with something darker in color, it will just warm it up, right.
Speaker 2: And Cok has also pointed out that dust can also
Speaker 2: cool the planet by depositing key nutrients like iron and
Speaker 2: phosphorus into the ocean to support the growth of CO
Speaker 2: two absorbing phytoplank Then, so you know, there are all
Speaker 2: these different ways that dust interacts with climate, and it
Speaker 2: seems like they're warming properties that can go on, they're
Speaker 2: cooling properties, and it may be that it's a little
Speaker 2: more in the cooling category at least right now.
Speaker 3: But if I understand you right, you're saying that that's
Speaker 3: there's enough uncertainty there that that's sort of a low
Speaker 3: confidence conclusion.
Speaker 2: There's the more that I look at it, the more
Speaker 2: that it seems like we're still learning a lot more
Speaker 2: about how dust were in the atmosphere and exactly like
Speaker 2: what our data sets are and what the modeling looks like.
Speaker 2: But coxmin point here, and this is reflected in the
Speaker 2: Monroe article. I referenced earlier, is that this is not
Speaker 2: an argument for Okay, this is what we need to
Speaker 2: do to combat climate change or reverse it or the
Speaker 2: reverse of this. You know, It's not some sort of
Speaker 2: like weird biohacking geo hacking scheme or whatever. But rather
Speaker 2: it's about identifying because we we've probably discussed some of
Speaker 2: these before and you run across these where it's like,
Speaker 2: all right, what we need to do. We need to
Speaker 2: pump x number of particles how many tons of particles
Speaker 2: into the atmosphere to carry out some sort of cooling
Speaker 2: effect to counteract global warming.
Speaker 3: That is not being advocated here right.
Speaker 2: Rather, the point here is that we need to identify
Speaker 2: to what degree atmospheric dust levels may impact and even
Speaker 2: mask the effects of global warming. And its key since
Speaker 2: microscopic airborne particles created by burning fossil fuel or of
Speaker 2: course a huge aspect of human caused climate change, but
Speaker 2: those very particles could also temporarily be contributing to cooling.
Speaker 2: So we need to be aware of all this so
Speaker 2: that first of all, we know the degree to which
Speaker 2: you know to which climate change is occurring and isn't
Speaker 2: masked by the effects of the dust in the atmosphere,
Speaker 2: and then also we need to be aware of this.
Speaker 2: If we do hopefully ratchet down on our fossil fuel consumption,
Speaker 2: you know we're likely going to see some sort of
Speaker 2: dip in the cooling effect. There that there were the
Speaker 2: specific cooling effect caused by the dust particles that are
Speaker 2: created via the burning of fossil fuels. Now, satellites can
Speaker 2: detect dust in the atmosphere, but I was reading about
Speaker 2: how this doesn't mean it's necessarily always easy to detect.
Speaker 2: It can apparently be quite challenging, but the results can
Speaker 2: also be very impressive, very informative. Apparently there's still a
Speaker 2: lot of discussion over how how much dust there is
Speaker 2: and how it impacts everything. I was looking at a
Speaker 2: twenty twenty four article in The Washington Post by Aaron Blakemore.
Speaker 2: This is not a pair of recent studies that challenge
Speaker 2: the North African dust emission dominance view that we referenced earlier,
Speaker 2: and instead argue that dust emissions may vary by season
Speaker 2: and across hemispheres, and that the total worldwide dust emission
Speaker 2: level might actually be much lower than previously thought. So
Speaker 2: that would mean our older models may be in need
Speaker 2: of some update, and I believe the issues we've just
Speaker 2: discussed your concerning climate and fossil fuel usage. I mean,
Speaker 2: these are still extremely valid. But this is another example
Speaker 2: of how we need more research. We need better data sets,
Speaker 2: better tracking. All this is probably needed to get a
Speaker 2: handle on the exact impact and variance of Earth's atmospheric dust.
Speaker 3: So, despite common symbolic themes, on a global scale, dust
Speaker 3: is the opposite of insignificant. It has large scale ramifications
Speaker 3: and we need to understand them better. In how dust
Speaker 3: affects climate, weather, water, all of that.
Speaker 2: Yeah, human health, and then you know, to get into
Speaker 2: the dust mites as well, allergens and so forth. Yeah,
Speaker 2: so it's like dust at the beginning, dust at the end,
Speaker 2: and then just dust all in between as well, you know,
Speaker 2: making it rain, making it hot or cold, making us sick,
Speaker 2: making us feel like our house is a bit foul
Speaker 2: and needs to be cleaned up, all of these things.
Speaker 3: All right, Well, maybe we should call part one there,
Speaker 3: but we will be back with more to say about
Speaker 3: dust next time.
Speaker 2: That's right, there's a lot to discuss regarding dust. We
Speaker 2: didn't get into cosmic dust at all. I'm sure we'll
Speaker 2: get into that We already have some topics lined up involving,
Speaker 2: you know, philosophical and mythological treatments of dust, so expect
Speaker 2: more of that as well. In the meantime, I'll remind
Speaker 2: everyone that Stuffed Blow Your Mind is primarily a science
Speaker 2: and culture podcast, with core episodes on Tuesdays and Thursdays.
Speaker 2: On my days, we do listener mail. On Wednesdays, we
Speaker 2: do a short form episode on Fridays. We set aside
Speaker 2: most serious concerns to just talk about a weird movie
Speaker 2: on Weird House Cinema. And indeed, more than one movie
Speaker 2: we've watched quite a few movies have involved evil creatures
Speaker 2: turning to dust. I think we just watched one a
Speaker 2: couple of weeks ago where this happened at the end.
Speaker 2: Which one was this was this Wolf Woman where the
Speaker 2: villain turns to dust and then a wind suddenly blows
Speaker 2: all the dust away.
Speaker 3: Yeah, Wolf Devil Woman. Yeah, the evil demon at the
Speaker 3: end turns into soot.
Speaker 2: Yeah. So there's plenty of dust on Weird House as well.
Speaker 3: And then it doesn't tell you if the main character
Speaker 3: lives or not. She just like is getting kind of woozy,
Speaker 3: and then the cuts to the end the end.
Speaker 2: Yeah, so yeah, that's the Stuff to Blow Your Mind
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Speaker 2: you like what we're doing here. One thing you can
Speaker 2: do to help us out is rate and review us
Speaker 2: wherever you get the you have the power to do so.
Speaker 2: Give us a nice array of stars, a little sprinkling
Speaker 2: at dust there if you will, it helps us out.
Speaker 2: And if you know, if you have any thoughts on
Speaker 2: this topic about past topics, future topic possibilities, ride in
Speaker 2: and let us know. We would love to hear from you,
Speaker 2: and email is the best way to get in touch
Speaker 2: with us directly.
Speaker 3: Huge thanks as always to our excellent audio producer JJ Posway.
Speaker 3: If you would like to get in touch with us
Speaker 3: with feedback on this episode or any other, to suggest
Speaker 3: a topic for the future, or just to say hello,
Speaker 3: you can email us at contact at Stuff to Blow
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