Pollution
Pollution is represented as an abstract "cloud", calculated per chunk and visible on the minimap and Map, when Alternative view is on (default Alt-Key).
It is produced by many buildings involved in processing items and spreads outwards at a steady rate.
Here are some charts to do with Pollution/De-Pollution.
Native life
Pollution attracts biters to your factory. Biters who find themselves in a polluted area will attempt to reach the source of pollution and destroy it.
Each spawner absorbs 20 + 0.01 * [chunks pollution] every game second (60 ticks), if the chunks pollution is greater than 20 otherwise it absorbs the total pollution.
After a certain amount of pollution is absorbed the spawner adds one biter/spitter to the next attack wave. Every 1 to 10 minutes (random) the gathered biters launch an attack. If not all biters have arrived at the rendezvous point by that time, they will wait up to an additional 2 minutes for stragglers.
Required pollution to add an additional biter/spitter to the attack wave:
| Pollution | Type |
|---|---|
| 200 | Small biter |
| 1000 | Medium biter |
| 4000 | Big biter |
| 20000 | Behemoth biter |
| 200 | Small spitter |
| 600 | Medium spitter |
| 1500 | Big apitter |
| 10000 | Behemoth spitter |
With 1350 absorbed pollution at the time of attack the following wave consists of 6 small biters and 1 medium biter OR 6 small spitters and 2 medium spitters depending on the spawner's type and evolution factor.
Pollution dissipation
- slowly (0.6 units per tick) at every Chunk (32x32) of map it covers. So the more the pollution spreads, the more is absorbed.
- Trees also absorb some pollution (See Pollution Production#De-polluters).
- Spawners absorb some pollution, but this will increase difficulty by raising the Evolution factor.
- In certain Mods it is possible to build devices or trees which reduce pollution.
Modules
Modules that list "+x% pollution" increase pollution multiplier, not a flat pollution rate. Final pollution value is (pollution multiplier * energy usage multiplier * base pollution), meaning heavily boosted buildings are likely to account for most of the pollution produced in a factory.