You couldn't walk outside in the Philadelphia region Wednesday and Thursday without smelling smoke in the air and seeing haze in the air.
The unhealthy air quality is due to wildfires burning in Canada and blowing down to Pennsylvania, New Jersey and Delaware.
You can track the current Air Quality using this map:
Here are images showing the hazy conditions over Philadelphia the past couple days:
Center City Philadelphia - Thursday
Atlantic City - Thursday
Schuylkill River - Thursday
Philadelphia International Airport - Thursday
Philadelphia Skyline - Wednesday
Citizens Bank Park - Wednesday
Philadelphia City Hall - Wednesday
View Over the Delaware River - Wednesday
Pocono Mountains - Wednesday