Wildfire smoke updates: CDC issues health alert on wildfire smoke exposure
The smoke is forecast to dissipate over the weekend.
Millions of Americans are on alert for unhealthy air quality as smoke from wildfires in neighboring Canada drifts to the United States.
Wildfires have burned a record of 20 million acres across Canada so far this year, with no end in sight. There are currently 500 active wildfires throughout the country and more than 250 have been deemed out of control, according to the Canadian Interagency Forest Fire Center. The smoke has been making its way to the U.S. for over a month.
Latest headlines:
Air quality alerts in 21 states
Air quality alerts are in effect in 21 states Thursday afternoon as the Canadian wildfire smoke infiltrates the Midwest, Northeast and parts of the South.
Pittsburgh air quality 'very unhealthy,' MLB game delayed
The Air Quality Index in Pittsburgh climbed to 231 Thursday afternoon, which falls under the "very unhealthy" category. Any number over 100 is considered unhealthy for sensitive groups.
Thursday afternoon's MLB game in Pittsburgh between the Pirates and San Diego Padres was delayed 45 minutes due to the poor air quality, according to The Associated Press.
Pittsburgh Mayor Ed Gainey is encouraging residents to stay inside on Thursday.
New York to roll out air quality phone alerts
New York will be rolling out phone alerts to remind residents to take precautions amid the poor air quality, Gov. Kathy Hochul said Thursday.
The Air Quality Index is currently in the "unhealthy" category in Rochester and Buffalo.
"The truth is, there is no end in sight," Hochul said at news conference, noting the conditions could linger off and on through the summer. "This is the new normal for New Yorkers."
Phone alerts will be sent in areas where the Air Quality Index is above 200 for one hour or longer. Announcements will also be made on mass transit, where hundreds of thousands of masks will be handed out.
Hochul said it is too early to know about the air quality over the July 4 holiday.
“We don't know what is going to happen beyond the next couple days -- today will be very bad, tomorrow will be very bad. We expect to see the winds start to dissipate over the next couple days. It is impossible for us at this point to predict the holiday celebrations," she said.
Jackie Bray, commissioner of New York's Division of Homeland Security and Emergency Services, added that it's "totally appropriate to keep the pools open today, totally appropriate for people to be out, as long as they don't fall into these sensitive groups."
-ABC News' Aaron Katersky
Columbus, Ohio, hits its worst air quality ever
Columbus, Ohio, hit an Air Quality Index of 244 on Thursday morning, the highest reading ever for the city.
The AQI has since lowered to 169. Any number over 100 is considered unhealthy for sensitive groups.
-ABC News' Jeremy Edwards