Air Quality Worsens In Philly Region, Code Red Declared

PHILADELPHIA — The Philadelphia region is in under a Code Red Air Quality Action Day declaration for Thursday after officials Wednesday said Thursday would be Code Orange.

Smoke from wildfires in Canada are still the driving factor for the poor air quality.

"We do expect this heavy plume of smoke that moved in during the overnight period to thin out during the day today," the Pennsylvania Department of Environmental Protection said. "As the plume thins, [particulate matter] levels are likely to drop. By the afternoon, [particulate matter] concentrations will likely be in the Code ORANGE to Code RED still."

Vulnerable populations, such as children, the elderly, and those suffering from respiratory illnesses, are urged to avoid going outside.

Outdoor time should be limited for all people, however.

Officials said a dense plume of smoke settled onto the Philadelphia region late Wednesday, and thankfully models do not predict another such plume for Thursday.

A low pressure system is shifting winds from east to west in eastern Canada, changing the smoke plume's orientation.

"Instead of driving in smoke from a more northerly direction, the smoke will have to travel a longer distance and make its way into the Commonwealth from the northwest," officials said. "The orientation of the plume of smoke impacting the northeastern US will modify each day as the area of low pressure over Canada finally begins to jettison out into the Atlantic."

The smoke is expected to disperse Saturday into Sunday, with particulate matter levels declining, the DEP said.

The frequency, extent and severity of wildfires mark important indicators of climate change, environmental officials say. The peak of the nation's wildfire season is also occurring earlier — peaking in August from 1984-2001 and then in July from 2002-20, according to research from the U.S. Environmental Protection Agency.