Title says it all.
I'm working (very slowly) on an addon to rebalance IR3 for Space Age, and I'd like to make it so ammonia (both the gas and liquified gas from IR3) cause "spore spills", meaning venting the gas would attract Pentapods to factories that produce it. (It wouldn't be a "regular" pollutant though)

This would force the player to choose whether to break it down into harmless N2/H2 gases, or defend ammonia vents from angry starfishes.
It would have a role similar to CO2 on Nauvis.
(In my addon's case, "spoilage processing" and "gleban air separation" would produce ammonia)

I've been looking through the data-stage document and other various lua code blocks, and I'm a little lost regarding how to implement that.
Can IR3's pollution spill system do that? Which functions would need to be rewritten to feature "spore" instead of "pollution"?

The way I understand the mechanic is that it will spawn whatever pollutant is appropriate for that surface, it doesn't differentiate. Breaking a crude oil tank on Gleba will create spores.

If you want it to behave differently for fluids on different planets, then I think I would need to rewrite some of it on my side.

I haven't been paying much attention to the pollution spill mechanic because it is currently part-broken.

Okay I have a new build available for you to test on Codeberg. Now, you should be able to call this function which accepts a new optional third argument:

DIR.set_fluid_spill_multiplier("ammonia", 1.0, "spores")

You can even declare a separate multiplier for "pollution" on the same fluid if you wish.

(While you're at it, could you take a look at the rubber trees and tell me what you think?)

[...] Now, you should be able to call this function which accepts a new optional third argument:

DIR.set_fluid_spill_multiplier("ammonia", 1.0, "spores")

You can even declare a separate multiplier for "pollution" on the same fluid if you wish.

Awesome! That's perfect. :)
I originally intended only for ammonia to produce spore, but I might add a few other gases if I see fit. (probably sour gas or natural gas)

(While you're at it, could you take a look at the rubber trees and tell me what you think?)

I've generated a few worlds and so far, it seems pretty good. Deserts still suck, but that's deserts.
They feel a little close to spawn, but as long as you can't trip on them while you're still in the boiler phase, it'll be fine.

Most of them spawned as far as tiny biter nests, if not near them, forcing the player to risk their forestries if they don't clear out nests.
Since forestries absorb pollution though, it shouldn't be a problem. All in all, pretty neat and less of a pain!