{
  "CarbonMonoxide1971Area": "Billings Area, MT",
  "Lead1978Area": "Lewis & Clark County (part); City of East Helena and vicinity, MT",
  "Lead2008Area": "Washington, DC-MD-VA",
  "NitrogenDioxide1971Area": "Los Angeles-South Coast Air Basin Area, CA",
  "Ozone8hr1997Area": "Milwaukee-Racine, WI",
  "Ozone8hr2008Area": "Chicago-Naperville, IL-IN-WI",
  "Ozone8hr2015Area": "Chicago-Naperville, IL-IN-WI",
  "ParticulateMatter1987Area": "Lake County; Cities of East Chicago, Hammond, Whiting, and Gary, IN",
  "ParticulateMatter1997Area": "Washington, DC-MD-VA",
  "ParticulateMatter2006Area": "Washington, DC-MD-VA",
  "ParticulateMatter2012Area": "Los Angeles-South Coast Air Basin",
  "SulfurDioxide1971Area": "Lake County: (part), IN",
  "SulfurDioxide2010Area": "Washington, DC-MD-VA"
}