YOUNGSTOWN - Ohio and Pennsylvania's environmental agencies are both issuing advisories for air quality as Canadian wildfire smoke once again creeps it's way into the valley.

The Ohio EPA issued a statewide Air Quality Advisory, while the Pennsylvania DEP has issued a statewide Code Orange Air Quality Action Day.

Environmental experts expect the Air Quality Index to be in the “unhealthy for sensitive groups” to “unhealthy” ranges.

According to the Eastgate Regional Council of Governments, the most recent hourly estimate of Particle Pollution (2.5 microns) in the Mahoning Valley reached 159 AQI, which is considered to be an Unhealthy level.      

Air quality data compiled on AirNOW.gov shows the AQI for many regions throughout Northeast Ohio and Western Pennsylvania to be at 'unhealthy' levels, with readings from Warren, Youngstown, and New Castle all reaching 155 AQI or higher. 

When AQI reaches unhealthy levels, children and people with asthma are the groups most at risk. There is an increased likelihood of respiratory symptoms and breathing discomfort in active children and adults, and people with respiratory disease.

U.S. EPA cautions that "active children and adults, and people with lung disease, such as asthma, should reduce prolonged or heavy outdoor exertion." 'Prolonged' generally means lasting four or more hours with short rest periods. 'Heavy exertion' is that which would increase the resting breathing rate four fold or greater.

The advisories in both states are in effect through the end of Monday, July 17.