Environmental Stress Index (ZPG) is a survey to determine the quality of life in American cities. Zero Population Growth, Inc. based in Washington D.C., conducted this "Urban Stress Test" in the late 1980s. One hundred and ninety-two cities were selected throughout the United States. The population-linked survey was based on 11 criteria: Population change; Population density; Education; Violent crime; Community economics; Individual economics (percent below federal poverty level and per capita income); Births (percent of teenage births and infant mortality); Air quality (meeting Environmental Protection Agency (EPA) standards); Hazardous waste (number of EPA-designated hazardous waste sites); Water (quality and supply); Sewage (model cities provide better than secondary treatment of their wastewater).

Cites were ranked one to six with number one being best. The cities with the lower scores were called model cities. The cities with the higher scores were called the stressed cities. Among the model cities were Abilene, Texas, with an index of 1.6; Roanoke, Virginia, 1.6; Berkeley, California, 2.0; Colorado Springs, Colorado, 2.0; and Peoria, Illinois, 2.0.

Among America's worst cities were Phoenix, Arizona, 5; Houston, Texas, 4.5; Los Angeles, 4.3; Honolulu, Hawaii, 4.3; and Baltimore, Maryland, 4.3.