Again pollution

[ramses II.]

Again pollution.
Does the appeareance of pollution skulls also depend from the number of cities or the number of inhabitants? I'm just playing a game (just researching future techs) where a city with a size of 2 is polluted (city has temple, market place and a factory - three specials, all desert oil).

The other question I have:
Getting mass production, the appearence of pollution skull seem to increase. Did you notice that, too?

[Zenon]

Ramses, the base factors for pollution are city size and shield production. IIRC mass production is one of the techs to increase pollution. For details on the many modifiers there is an excellent thread linked in the Great Library.

Zenon

[N35t0r]

IIRC, Industrialization increases population-based pollution.

Also, population and shield based pollution are treated separately. I know that as from the 20th shield, you start getting one skull for each extra shield (first skull for the 21st shield). This is without having a Rec. center or Solar / Hydro plant.

In the case of your city, i guess that's what happens:

If you're working both oils, you have 4 shileds each +1 mine? each and +2 extra each for a RR?, which would add up to a maximum total of up to 14 shields. a factory would add an extra 7, bringing it up to 21, meaning one skull. (and if you have Hoover's, even more)

Not to mention you have at least one shield from your city tile.

[Six Thousand Year Old Man]

IIRC learning Plastics will also increase your chance to get pollution. How much, I can't recall.

[N35t0r]

Linked from the GL, at a post by Starlifter in CFC:

Pollution icons consist of two sources, added together... Population Pollution (PP) and Resource Pollution (RP).

Population Pollution
--------------------

PP = (CP * TM) / 4 (round down)

Before Industrialization, TM = 0
After Industrialization, TM = 1

TM is further modified by this:

Auto +1
Mass Production +1
Plastics +1
Sanitation not discovered +1
Environmentalism -1
Solar Plant -1
Mass Transit TM=0


Resource Pollution
------------------

RP = (SP / RPD ) - 20

Improvement RPD
----------- -------
Nothing 1
Hydro 2
Nuclear 2
Recycling 3
Solar 9999 (infinity)


TP = RP + PP (round down)

P = DL * (A / 2)

RN = Random Integer between 0 and (256 - P)

If RN < (TP * 2) then you get 1 pollution within the city radius


KEY:
------------------------------------
TP = Total Pollution Icons
(it is the # of pollution icons you see in city status)

PP = Population Pollution

CP = City Population (Size of city)

TM = Tech Multiplier

RP = Resource Pollution

SP = Shields Produced

RPD = Resource Pollution Divisor

DL = Difficulty Level
(0-Cheftian, 1-warlord, 2-Prince, 3-king, 4-Emperor, 5-Deity)

A = Number of advances since 4000 BC
(this EXCLUDES the advances you started with!!!)

RN = Random Number (an integer)

As you can see mathematically, after you discover the 102nd advance at deity, you are guaranteed to get pollution every turn, even if you have only a single pollution icon (the yellow triangle) in your city status. This translates to Future Technology 15.... after that, even one pollution icon in a city status screen will yield one polluted terrain.

As everyone doubtless knows, there are 87 normal advances, assuming zero at the start. If you had 5 starting advances, then the last discoverd advance (assume stealth) would be number 82, which is used in the pollution calculation (variable A).

This yields a lower probability of pollution in a city that has a pollution icon. It also means that 100% probability of pollution will not occur for a single pollution icon until the 20th Future Technology is discovered at Deity.

So as you can see, pollution probability is affected by the total number of advances that you discover during the game. The starting techs do NOT count to this total, thus your probability of pollution will be lower at any given number of advances you have discovered.

Note: Original equation references are mostly from the Civ II Official Strategy Guide.