Per Capita Total Cost for Cities with Different Incomes and PM_2.5 Concentrations

CNY = yuan, PM_2.5 = particulates with aerodynamic diameter ≤2.5 μm.

Notes: Cities are divided into five equal groups according to urban per capita disposable income, from the 1st (lowest income group) to the 5th (highest income group). Circle size represents the affected population in each city. $1 = CNY6.64 (2016 average prices).