Why isn't my beautiful city of light full of smog from the factories right below it?

Question

Background

The vast mechanical wilderness of the Works is shaped like a cone. At its peak is the (artificial) Sun, which sheds warmth and light via [complicated magic system thing]. The light from the Sun filters down through layers of infrastructure and machinery which grow of their own accord. Keep traveling down and eventually you'll reach the night-lands. Nobody knows how far down they stretch; the Works may extend downwards and outwards forever.

The Sun is surrounded by a town, populated mostly by the devotees of the religious group who worship it as a deity of vision and knowledge. This town was the earliest place inhabited in the Works, back when the Works was small and you could climb from its top to its bottom in only a day. Let's call it High Town.

Centuries ago, High Town grew into High City, and so it expanded downwards, because where else was there to go? In the lower layers, the dusk-lands, plucky humans built factories and generators and UV-lit industrial farms and all sorts of other things which produce delicious, thick, poisonous smog.

But we can't have smog in High City, because that would block the holy light of the Sun. So what can they do about it?

Notes

This world is soft sci-fantasy, so there's no pressure to be scientific - though I am open to scientific responses too! (For example, if there was a chemistry-based way to get rid of all of the smog).

Finally, a note on the edges of the Works: the peak has a wall/roof, but in lower areas the edges just leak out into unreality. It's a good place to dump unwanted things such as toxic fumes - but how to get them out there?

TL;DR

My world is a cone, and the point of the cone needs to be kept free of pollution. Where do all the fumes from industry, lower in the cone, go?

Answer 1

I don't think a cone-shaped world needs to worry about smog at the top of the cone. It's the bottom that needs to worry.

Smog can form in almost any climate where industries or cities release large amounts of air pollution, such as smoke or gases. However, it is worse during periods of warmer, sunnier weather when the upper air is warm enough to inhibit vertical circulation. It is especially prevalent in geologic basins encircled by hills or mountains.

^{Source: Wikipedia (emphasis, mine)}

Assuming your cone world is pointy side up with the artificial sun at the top, smog should collect down below. As long as you hand-wave gravity and air currents you should be good.

You hit a little snag if your cone world goes down forever — or maybe this isn't a problem — but since smog collects in low areas, it should sink to infinity. I suppose you could always hand-wave this, too. The further down you go, the smoggier it gets. Don't provide a reason unless you need to. It can simply be a characteristic of your world just like its cone shape. People already need to suspend belief for a cone world.

Answer 2

There are two neat ways that immediately sprang to mind:

The higher the Smog rises, the closer it is to the source and therefore more concentrated UV Rays, which breaks down the smog

So this may require a little bit of Handwaivery - but the basic premise is that as the Smog rises, it starts to get broken down by the Sunlight or UV Radiation. Just how things get bleached from prolonged sun exposure in the real world.

By pure fortuitous circumstance, the higher the Smog starts to rise, the more concentrated the affects of the artificial sun, which speeds up the break down of the particles in the Smog - thus meaning the air around the Holy city is always clean.

Rain Rain go away, wash the smog out another way

So - when you say Holy City - the first thing that springs (pun intended...) to mind is a lush paradise of a world, maybe a few temples - but most importantly - lots of greenery and plants and rivers, streams and other things.

Instead of draining to the Ocean, the Water falls off the edge of the holy city, and via surface tension and other gubbins rides along the roof of the factory area, condensing into Rain.

The Rain acts to stop the heavy smog particles from rising - cooling them and bringing them to the ground, stopping them from ever reaching the Holy City.

This constant rain has some other benefits for the industrial city - such as cooling machinery, washing the waste off the streets etc.

Answer 3

Dump it.

Solid and liquid waste products can be easily disposed of using gravity. Just dig a shaft deep into the lower levels and throw your garbage down the chute. Or build a slide at the edge and let your trash run down the side of the cone. This also works for heavier than air gases, which actually covers the majority of industrial byproducts as other users have pointed out. Carbon dioxide is heavier than air after all.

So what about the lighter than air gasses? Simple: just make them heavy. There’s two options for this:

1. Perform a chemical reaction to bond the gas with other elements to form a heavier compound. Your options will be limited by the composition of the gas and what other elements you have access to.

2. Package the gas into a pressurized container. This is pretty wasteful, but it’s worth it if it’ll keep the air around the Holy Sun clean.

Now that our lighter than air gasses have been made heavier than air, we can dump them using our standard trash disposal method of choice.

Answer 4

The smog is sent downwards instead of upwards

Your world behaves somewhat like mechano-worlds of Warhammer 40000, where the lower levels have harder life conditions to the point of no one living too deep, and occasionally Something Bad (tm) forms somewhere below for the dwellers to combat. Also you are not bound to real world physics (and most likely have no place for atmospheric circulation for the first place) to give factories chimneys, therefore you can devise those factories so that the smoke or any exhaust they produce is evacuated to the lower levels, which may in turn respond to their environmental threat by containing it and redirecting even lower, as far as they can venture into the permanent darkness. (Probably all the machines in there are solar-powered so their interference in the dark is limited by their power storage.)

Eventually, other layers that don't know this technique before would adapt and create their own exhaust systems bringing waste downwards, be it smoke or acid or ash, so the dark levels would have clusters of tubes going down that drip various substances at their ends, that may undermine (if you so desire) the basement of your world.

PS: check if your sunlight can penetrate the ground of the High City, or else the second highest layer would be totally dark already.

Answer 5

Air currents force the smog into awe inspiring back tendrils towards the peak

Smog particles are heavier than normal air particles and for some reason the air currents beyond the cone tend to gather the heavier smog particles into ever tighter air streams the further towards the cone's summit one goes.

By the time one reaches the height of High Town, the tendrils of compressed Smog particles look like literal black streams of compressed evil which (by your preference) either seem to be devoured by the sun, rush past the sun or seem to be deflected by the sun as the smog streams at a certain point seem to veer off sharply into space. Which ever choice you go with, the worshipers of the sun god consider this occurrence to be proof of and deliberate intervention by their sun god. The air streams which condense and dispose of the smog towards the summit are ever changing and unpredictable, so the sun worshippers obviously take the view that this necessitates extensive worship of the sun god - as if these unpredictable air streams ever stop carrying the smog away from High Town, it would serve as proof of the sun god's displeasure at the lack of devotion from his supplicants.

While the compressed slipstreams of smog can be seen with the naked eye in the skies above High Town, they are usually far away enough that one doesn't notice them unless you look carefully - as to not ruin the view.

Answer 6

...if there was a chemistry-based way to get rid of all of the smog...

If humanity knew how to do this on even a city-sized scale, Earth would be fundamentally free of airborne pollution and the inventor a very wealthy person. Alas, no such technology trivially exists. Gratefully, you're not demanding a science-based answer. I therefore recommend:

All airborne factory output is captured and piped to reclamation centers that coalesce the smog into a carbon-and-toxin-heavy dirt that is then exported to the nearest deep-crater volcano for disposal.

In reality, this would have substantial problems because...

...anything that restricts the free release of pollution has a cost.

• E.G. adding catalytic converters to cars reduced the horsepower the car could produce, which means to get the same performance the car must burn more gas... which requires more catalytic conversion, which further reduces performance.... Said simply, energy is required to remove pollutants, reducing efficiency.

• Adding pipes and reclamation centers costs money... and a lot of it.¹

• Volcanoes emit pollution and are, in fact, one of the biggest pollution-generators on the planet. While dumping the coalesced smog into a volcano would help, it would nevertheless result in some (a bit more than some, actually) of the pollution re-entering the atmosphere.

Or you could use the coalesced smog as printer toner. :-) That's not quite as unreasonable as it sounds, but you'd not get a lovely black from it. Why don't we do this today? Well... cost.... That and the reality that coalescing any part of an atmosphere into a solid dirt-like mass is no small feat, which is why humanity has opted to just let the dust settle.

Gratefully, you're willing to ignore all that. Bless you.

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_{¹ Curiously, almost no worldbuilder wants to consider economics when they build their worlds — and yet they often want the most scientifically plausible fantasy-world solutions they can get.}

Answer 7

"peak is the (artificial) Sun, which sheds warmth and light via .. magic"

You have magic that creates heat.. so if you can make one magic sun you can make two and plonk one inside a really big boiler to heat the water, or lots of little ones for lots of smaller boilers.

If you can create heat by magic that can be the 'fuel' to power Steam Turbines.

Magic smokeless fuel = no smoke > no smoke = no smog > no smog = no problem.

All you have then is a bit of steam.. so build a few big Cooling Towers above ground to disperse any excess steam and you've nothing but some small fluffy white clouds far above ground level that should tend to disperse almost as quickly as you pump it out.. if you don't want anything above the surface condense it out (naturally on cooler upper level tunnel and cave walls to then trickle and flow back to the bottom if you want) and feed it back into the boilers to boil again.

Use your steam turbines to drive whatever tech you want.. cogs, gears and flywheels, or electricity, doesn't matter which, you can use them for either.

If you're worried the tech is too advanced don't be, a Steam Engine doesn't have to be complex, far from it, check out the aeolipile in the link, a Greek came up with that in the 1st century, and cooling towers are basically just big odd shaped chimneys when all's said and done.

...

"In the far ancient past my son, or so the tales tell us, there were two suns in the city, the one we know at the top and another in the deepest depths of below, but then the builders enclosed the one in the depths in a great bowl of bronze, or so the tales say, and that became the device that drives all"

Answer 8

Light a candle. Notice how little visible smoke it sheds when burning full force. Only when you quench it does the smoke thicken.

Smog is not produced by pure combustion, which produces carbon dioxide and water vapor, both invisible to the naked eye. Smog is produced by incomplete combustion and by contaminants in the fuel.

So they purify the fuel before it gets shipped to the city -- possibly even because the decrease in weight and the increase in heat is worth it in itself -- and then they ensure it is burned with great heat and exactly the right amount of air to keep the flame pure.