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Smoke, alerts, and PM2.5
Wildfire smoke from Canada and Minnesota has prompted air-quality warnings across the U.S., with the Pennsylvania Department of Environmental Protection saying air quality will worsen Thursday evening and urging people to limit their time outdoors.
Pennsylvania declared a Code Purple Air Quality Alert for Friday, meaning levels of particulate matter will be dangerous to everyone, including those who are healthy, and the agency said conditions can vary by zip code while advising residents to check AirNow.
The WHYY report said the fine particles, known as PM 2.5, are 30 times smaller than the width of human hair and are easily inhalable, with the particles able to settle deep in the lungs and enter the bloodstream.
Ruth McDermott-Levy, co-director of the Mid-Atlantic Center for Children’s Health and the Environment at Villanova University College of Nursing, said, "Wildfire smoke is among the most toxic air pollution that we can have," and linked the toxicity to burning things like wood and other materials not meant to be burned and breathed.
Where it’s worst
In the upper Midwest and Northeast, the WHYY and WKBN/NEXSTAR coverage described smoke moving across multiple states, with WKBN/NEXSTAR saying conditions are expected to spread into Friday and reach further south through the Midwest and into Appalachia and the East Coast.
WKBN/NEXSTAR reported that northern portions of Minnesota had the worst air quality in the world as of Thursday morning, with the Environmental Protection Agency’s U.S. Air Quality Index showing an AQI of 1,421 at 10 a.m. ET in north central Minnesota.
The same report said purple on the AQI map signifies a “very unhealthy” air quality index of 201 to 300, while maroon represents a “hazardous” level of concern marked with an AQI of 301 or higher.
For Philadelphia, WKBN/NEXSTAR said the city had an AQI of 182 at 9:30 a.m. ET, putting it squarely in the unhealthy range, and it described parts of New York and Pennsylvania shaded in red on the EPA’s AQI map as “unhealthy.”
Health risks and guidance
WHYY said breathing in particulate matter can cause respiratory and cardiovascular problems and impact vulnerable populations like children, the elderly and people with health conditions such as asthma, while also noting that even healthy people could feel effects as air quality worsens.
The report cited a New Jersey Department of Health finding of a spike in emergency room visits for new diagnoses of asthma when the 2023 Canadian wildfires led to poor air quality for several days in New Jersey, Pennsylvania and Delaware, and it quoted Dr. Sadia Benzaquen saying, "The bad [air] quality due to the wildfires can increase allergic diseases, and one of them is asthma."
WKBN/NEXSTAR added that the particulates can cause shortness of breath, coughing, dizziness or fatigue, and aggravate heart and lung diseases and other chronic health issues, and it quoted Tyler Hasenstein warning, "Those two things coinciding with each other is not good from a health perspective."
Across the region, guidance in the WHYY and WKBN/NEXSTAR reports emphasized limiting time outdoors and avoiding strenuous activity, with WHYY urging people to go to the emergency department if they experience chest pain and shortness of breath and WKBN/NEXSTAR suggesting an N95 mask if you have to be outside while keeping indoor air cleaner by closing windows and running an air purifier or air conditioner.
