TRM: Emission Tolerance

=== PART OF TRANSPORT REWORK MOD ===

Big towns put up with more, and distant smokestacks count for less.

In the base game every town judges noise and pollution by the same standard whatever its size, and every pollution source in its municipal area counts fully however far from the houses it stands. With this mod a city of 8,000 tolerates 6 dB more noise and 3 dB more pollution than a village, about two rating levels and one, and a farm 3 km outside a town adds about 1 dB to its pollution instead of 3 dB.

=== FEATURES ===

• Tolerance that grows with the town. Nothing changes up to 250 inhabitants. Above that, every doubling of the population adds an equal share of the chosen allowance until the population set under "Full Resilience At" is reached.
• Pollution weighted by distance. A source within 300 m of the nearest town building counts fully, and beyond that its weight falls evenly over the falloff distance down to the distant source weight. The heatmap and the sources themselves do not change, the town window shows the weighted rating.
• On top of the game's own settings. The allowance multiplies the game's Noise Sensitivity and Pollution Sensitivity settings, so Hard and Very Hard keep their stricter towns and "Off" stays off.
• Nothing written to the save. The mod changes how ratings are computed while it is active, so it can be added to or removed from a game at any time.

=== SETTINGS ===

• Noise Resilience ("Off", "3 dB", "6 dB", "9 dB", default "6 dB"). How much more noise a town tolerates as it grows. Nothing changes up to 250 inhabitants, then every doubling of the population adds an equal share of the chosen allowance until the population set under "Full Resilience At" is reached. 3 dB halves the sensitivity, the same step as from "Normal" to "Low" in the game's Noise Sensitivity setting, and is worth about one rating level. 6 dB is two such steps and 9 dB three. The allowance multiplies the game's own setting, so "Off" there still disables the rating. "Off" here leaves the noise rating as in the base game.
• Pollution Resilience ("Off", "3 dB", "6 dB", "9 dB", default "3 dB"). The same allowance for pollution, with the same steps and the same population ramp. "Off" leaves the pollution rating as in the base game.
• Full Resilience At ("2,000", "4,000", "8,000", "16,000", default "8,000"). The population at which a town reaches the full allowance. Between 250 inhabitants and this number the allowance grows by an equal step for every doubling of the population, so with 8,000 each doubling adds a fifth of it and a town of 2,000 has three fifths. The population is the "Current Population" shown in the town window.
• Pollution Weighting ("Base Game", "By Distance", default "By Distance"). How a town counts the pollution sources in its area. With "By Distance" a source within 300 m of the nearest town building counts fully, and beyond that its weight falls evenly over the "Falloff Distance" down to the "Distant Source Weight". Vehicles, industries, stations and depots are weighted alike, and the pollution heatmap does not change. "Base Game" leaves the rating as it is, and the two options below then have no effect.
• Falloff Distance ("1 km", "2 km", "3 km", "4 km", default "2 km"). The distance over which a source loses weight, measured from 300 m outside the nearest town building. With 2 km a factory 1.3 km past the last house counts at about 60% when the distant weight is 25%.
• Distant Source Weight ("None", "10%", "25%", "50%", default "25%"). How much a source beyond the falloff distance still counts. "None" removes distant sources from the rating entirely, "50%" keeps half of their effect. For a town whose pollution comes mostly from distant sources each halving of the weight is worth about 3 dB, a little more than one rating level.

=== INGAME EXAMPLES ===

• A town of 2,000 at the defaults judges noise as if the game's Noise Sensitivity were a little more than one step lower, 3.6 dB, nearly one and a half rating levels.
• A city of 8,000: as if it were two steps lower, "Very Low" instead of "Normal", about two and a half levels. Pollution gets half as much.
• A farm 3 km outside a town: about 1 dB on the pollution rating instead of 3 dB.

=== COMPATIBILITY ===

Stacks with per-town sensitivity set in the sandbox town editor and is independent of mods that change the emissions themselves. Nothing is written to the save. Option changes take effect at the next load.