Heavy smoke from hundreds of wildfires burning across Canada has drifted south, blanketing large swaths of the U.S. Northeast and Upper Midwest with fine particulate matter. The dense smoke has caused some U.S. cities to experience some of the worst air quality in the world.
The phenomenon is exacerbated by a meteorological “heat dome” that traps hot, smoky air close to the earth. These conditions are expected to persist, potentially exposing over 115 million people to dangerously polluted air through Saturday. Officials are advising residents to stay indoors if possible, utilize air conditioning and air purifiers, and wear N95 masks if venturing outside, while avoiding strenuous activity.
This event serves as a stark contrast to the significant progress made in reducing air pollution in the U.S. over the past six decades. Following World War II, booming industrial activity led to widespread pollution, with major cities routinely experiencing smog, falling ash, and toxic haze that caused immediate health impacts. The passage of the Clean Air Act 63 years ago marked a turning point, establishing a federal regulatory system that set limits on polluters. These regulations are credited with substantially cutting U.S. air pollution over the following 50 years and preventing hundreds of thousands of premature deaths.
However, recent years have seen an increase in certain air pollutants, particularly fine particulate matter from wildfires. The challenges in addressing climate change, which contributes to more intense and frequent wildfires, are more complex than tackling emissions from cars and factories. This suggests that while the U.S. has achieved considerable success in cleaning up its air, ongoing environmental threats like those posed by wildfires present new and more complicated challenges.
The current smoke event has led to a visible amber haze in some areas, with descriptions of the sky looking “genuinely apocalyptic” from regions closer to the Canadian fires.