Editing Pollution

{{Biotech}}
{{Stub|reason=Mechanics (Pollution spread / acidic smog % chance / wastepack cocoons), detailed analysis}}
'''Pollution''' refers to ''toxic'' pollution, largely as the byproduct of recharging [[allied mechanoid|friendly mechanoid]]s. Even using a [[wood-fired generator]] or [[chemfuel generator]] won't create it, for instance.

== Creation and Spread ==
==== Within Colonies ====
[[File:pollution_spread.png|400px|thumb|right|Ground pollution generated by a toxifier generator, visualized by the pollution overlay. The tiles under the player-built walls are polluted, though this does not show on the overlay.]]
Each [[toxic wastepack]] that is destroyed or disintegrates creates 6 tiles of pollution. Any means of destroying wastepacks creates pollution, except for the [[wastepack atomizer]].

A [[toxifier generator]] creates 6 tiles of pollution every 3 days. 

[[Defoliator ship]]s will pollute an expanding circle of tiles when landing, centered on the ship. This is in addition to the actual defoliation; the pollution is separate and spreads much slower.

Pollution created again in the same area will spread in an expanding circle. Natural rock walls block the pollution  spread, but player-made walls and other structures do not.

Pawns lingering in polluted tiles will accumulate [[Toxic buildup]] at a rate of 40% per day, assuming no [[Toxic Environment Resistance]] or [[Toxic Resistance]]. Unlike [[Toxic fallout]] or other map conditions, this is not mitigated by roofing the tile.

==== On the World Map ====
Dumping wastepacks on a hex utilizing [[caravan]]s or [[transport pod]]s will increase the pollution percentage of the hex by 0.05% per Wastepack dumped, or 1.3% per full transport pod. Once a world map hex reaches 100% pollution, any additional pollution gain will instead happen to one of its 8 possible neighboring tiles- this can spread pollution to the player's colony if one is not careful. 

Caravans walking through polluted terrain will accumulate [[Toxic buildup]] based on their [[Toxic Environment Resistance]] and [[Toxic Resistance]] stats. The unmitigated rate will be at 20%/day for Moderately Polluted tiles (50-75% pollution) and 40% per day for Extremely Polluted tiles (75~100% pollution).

Dumping wastepacks within 15 tiles of another faction settlement will cause the player to take a relationship penalty, scaling up with the number of wastepacks dumped and proximity to the settlement. Outlander and pirate factions may send a [[drop pod]] of waste back at you, while hostile factions can [[raid]] you.

Pollution may also exist from world generation, where certain tiles will be heavily polluted. You can configure the pollution coverage, with 5% as a default.

== Summary ==
{{Stub|section=1|reason = numbers and world tile and map tile effects}}
Pollution takes the form of polluted tiles. Polluted soil has a fertility of 50%, as long as the soil's original fertility is greater than 0%. Polluted soil can only grow a limited number of plants: [[Toxipotato plant|Toxipotatoes]], [[devilstrand]], [[psychoid plant|psychoid]], and a few types of trees (grey pine, deadbarrow cactus, etc.). Having polluted tiles increases the map's overall pollution, which causes a number of effects.

Colonists will receive [[toxic buildup]] from standing on these tiles.{{Check Tag|Detail Needed|How fast (with numbers) and exactly what conditions}} 

Pollution on the ground can be turned back into toxic wastepacks with a [[pollution pump]], or by ordering colonists to clean it up.

=== Acidic Smog ===
If there is enough pollution present within 4 tiles of your world tile, a weather effect known as Acidic smog will occur. How often depends on the level of pollution present. Tiles 2-4 spaces away have a 0.5x multiplier to pollution.

Acidic smog covers the outdoor area with a greenish haze, reduces light levels by {{--|28%}}, slows plant growth by {{Bad|x50%}} (stacking with reduced light for a total of {{bad|22%}} growth), gives non-immune colonists the {{--|5}} ''Acidic Smog'' [[mood]]let, and [[deteriorate]]s items at 300% speed. Items and pawns indoors are not affected by acidic smog in any way. Having the [[Genes#Total_antitoxic_lungs|Total antitoxic lungs]] or [[Genes#Tox immunity|Tox immunity]] [[gene]] renders immunity to the acidic smog moodlet.{{Check Tag|Other immunities?|Do other sources of total environmental toxproofing, such as detox lungs, affect the penalty? What about partial immunity?}}

Despite what players may expect, acidic smog itself does not have any negative health effects. The smog will affect pollution-friendly plants such as [[toxipotato plant|toxipotatoes]] the same as it does other plants. It does not provide or maintain [[Genes#Pollution_stimulus|Pollution stimulus]]'s effects.

=== Insectoids ===
Originally engineered as anti-mechanoid bioweapons, Giant [[insectoid|insects]] are drawn to pollution. When a toxic wastepack is destroyed, there's a chance for insectoid cocoons to emerge from the ground. These cocoons will hatch if a pawn comes within a small radius of it.

=== Pollution stimulus ===
{{Main|Pollution stimulus}}
Insects and humans with the [[Genes#Pollution_stimulus|Pollution Stimulus gene]] are stimulated by the toxic fumes of polluted terrain, making them faster and deadlier.
* Pollution stimulus (minor): 
** Moving x110%
** Consciousness +5%
* Pollution stimulus (moderate): 
** Moving x115%
** Consciousness +5%
* Pollution stimulus (maximum): 
** Moving x120%
** Consciousness +5%

== Pollution Mitigation ==
{{For|dealing with [[wastepack]]s themselves|Toxic wastepack#Disposal}}

=== Cleaning polluted tiles ===
* Having colonists manually clean pollution via the Zoning tab. This exposes them to toxic buildup.
* [[Pollution pump]]s automatically pick up pollution in the area when [[power]]ed.
* Letting [[polux tree]]s cleanly consume pollution. However, they only grow in sufficiently polluted areas, and seeds are difficult to come across.
Note that the former two ways of cleaning pollution up only turn it into [[toxic wastepack]]s, which then need to be [[Toxic_wastepack#Disposal|dealt with]] somehow.

=== Living with pollution ===
* '''[[Apparel]] items'''. [[Face mask]]s ({{+|50}}%) and [[gas mask]]s ({{+|80}}%) give [[Toxic Environment Resistance]]. This protects the user from accumulating [[toxic buildup]] as quickly.
* '''[[Artificial body parts|Artificial parts]]'''. The [[detoxifier kidney]] ({{+|50}}% [[toxic resistance]]) and [[detoxifier lung]] ({{+|60}}% environmental resistance) will slow the effects of pollution. Two organs of the same type will stop toxic effects of pollution.
* '''[[Gene]]s'''. Tox resistance gives {{+|50}}% toxic resistance. Partial antitoxic lungs give {{+|50}}% environmental resistance. Tox immunity or Total antitoxic lungs render full immunity to pollution and acidic smog.

Toxic resistance stacks additively with other sources of ''Toxic Resistance'', but stacks multiplicatively with Toxic ''Environment'' resistance. For example, a face mask and detoxifier lung, or face mask and partial antitoxic lungs, offers 100% resistance to pollution. A face mask and detoxifier kidney only provides 75% resistance to pollution.

== Version history ==
* [[Biotech DLC]] Release - Introduced.
* [[Version/1.4.3682|1.4.3682]] - Fix: Pollution overlay grid not updating after cell-filling buildings are destroyed.

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[[Category:Game mechanics]]