Another wave of smoke from the wildfires in Canada has moved into the United States, darkening skies, harming air quality and raising concerns about the increasing frequency of fires and what they have to do with climate change.
More than 100 million people are under air quality alerts from Wisconsin to Vermont to North Carolina as smoke from the Canadian wildfires continues south, though conditions are expected to slowly improve over the next holiday weekend.
NASA satellites have also recorded some of the smoke trails that span the Atlantic, as far away as Spain and Portugal.
Smoky air threatens a the Northeast and Mid-Atlantic regions increasingly, and New York officials warned residents to prepare, according to The New York Times.
According to Air Now, a website and app run by the Environmental Protection Agency that displays a map related to air pollution from fires, any reading above 100 on the air quality index is a warning for people with respiratory conditions take precautions.
The air quality index measures the density of five pollutants in the air: tropospheric ozone, particulate matter, carbon monoxide, nitrogen dioxide, and sulfur dioxide.
It was established by the Environmental Protection Agency as a way to communicate to Americans the state of the air they breathe each day. There are pollution monitors at more than 1,000 locations across the country.
Climate change has made once unbelievably high temperatures commonplace, and it's the “elephant in the room” that is making the fires worse and their effects on air quality, John C. Lin, a professor of atmospheric science at the University of Utah, told The New York Times.
As the United States prepares to celebrate the 4th of July, its neighbors to the north celebrate Canada Day on Saturday, but the type of group celebration that it normally involves is difficult or unsafe due to the air quality in various parts of the country.
In fact, in Montreal, poor air quality has led officials to cancel many outdoor activities and have begun issuing N95 face masks to residents, as recommended every time the air quality index exceeds 150.