|This page is about game mechanics.
This page is about game mechanics. It contains information such as formulas, costs, & other miscellany. See Category:Mechanics for other pages on game mechanics.
The Disease Rate determines how prevalent disease is in a city's population and, as a result, how many people are killed by disease. It is lowered by decreasing the population density of the city or by purchasing improvements like Hospitals (the decrease Disease directly) and Subways and Recycle Centers (that decrease Pollution and, as a result, Disease too, indirectly). It is increased by purchasing certain improvements that increase Pollution and by buying more infrastructure (increases Base Population and Population Density).
The Disease Rate cannot be lower than 0% and cannot be higher than 100% (known as Atzuya's limit). At 100%, a city will be losing population equal to 100 times it's Infrastructure (the formula for Base Population) and will therefore be left with the minimum population of 10.
There are two formulas pertaining to the Disease Rate. The first, is the formula used to determine the Disease Rate (as a percent), and the second is the formula that determines how many people, of a city's Base Population, are killed.
Note: Population Density is based upon the Base Population, not a city's displayed population.
DiseaseRate = ((((PopulationDensity^2) * 0.01) - 25)/100) + (Base Population/100000) + Pollution Modifier - Hospital Modifier
Pollution Modifier is the increase to disease, from increasing Pollution.
Pollution Modifier = PollutionIndex * 0.05
Hospital Modifier is the amount of disease reduced by buying Hospitals.
HospitalModifier = NumberOfHospitals * 2.5
PopulationLost = DiseaseRate * Infrastructure