Philadelphia-Camden-Wilmington, PA-NJ-DE-MD
- High ozone days per year: 75
- No. of days with unhealthy particle pollution: 3
- People with asthma: 546,311
- Population: 6,096,120
Another area that lies downwind of major sources of air pollution in the Midwest is the Philadelphia-Camden-Wilmington metro area. The area is also home to dozens of oil refineries and a busy interstate confluence.