(WHTM)– South Central and Eastern Pennsylvania are experiencing hazardous air quality due to the Canadian wildfires.

Hazardous air is when the air quality index (AQI) is given a value between 301 to 500, the AQI will be a maroon color and that means the air is dangerous for everyone to breathe even prompting emergency conditions.

“With conditions over much of eastern and central Pennsylvania in the Maroon or Hazardous Air Quality Index, residents should stay inside as much as possible until conditions improve,” Acting Secretary of the Department of Environmental Protection Rich Negrin said.

There are six different levels of air quality that is measured and range from zero to 500 by the U.S. Environmental Protection Agency (EPA). The higher the range, the worse the air quality is and it starts to be classified as unhealthy when the range goes over 100.

Conditions are expected to get better throughout the day and eastern Pennsylvania is expected to be moved into Code Red Air Quality while the western part will be moved to a Code Orange Air Quality Action Day. An Air Quality Action Day is declared when the AQI is forecasted to be Code Orange or higher.

Pennsylvania was issued a Code Red for air quality for the second day by the Department of Environmental Protection on Thursday. Meaning that the air is considered unhealthy, for the second day. The range for this is between 151 to 200.

Under Code Orange those with lung or respiratory conditions, children or those with weaker immune systems may experience some health effects.

Friday is when the air quality in Pennsylvania is expected to return to normal because of weather patterns.