Millions of Americans in 16 states are under dire air quality warnings as smoke from Canadian wildfires has led to hazardous conditions, with major metropolitan areas including Chicago, Detroit, Washington, and New York registering as some of the world's most polluted cities.
The National Weather Service has issued air quality alerts stretching from Minnesota and Illinois in the Upper Midwest to New York, New Jersey, and Virginia on the East Coast. According to the Environmental Protection Agency (EPA), the air quality is considered 'hazardous' from northern Minnesota to Columbus, Ohio, the agency's most severe rating.
The smoke originates from hundreds of forest fires in Canada, primarily in the province of Ontario. The airborne particles, known as fine particulate matter or PM2.5, are toxic compounds typically created by burning wood or industrial pollution. These particles are small enough to penetrate human tissue and can cause severe breathing difficulties, particularly for individuals with heart and lung conditions.
Health officials have noted that breathing in the current levels of PM2.5 in cities like Detroit, which reached 292.6 µg/m³ on Friday, is equivalent to smoking more than 13 cigarettes in a single day. In Chicago, PM2.5 pollution exceeded 240 µg/m³, comparable to smoking over 10 cigarettes daily.
The Air Quality Index (AQI) typically ranges from 0 to 500, with levels from 0-50 considered 'good' and 151-200 rated 'unhealthy'. The 'hazardous' zone, from 300 to 500 and above, warns everyone to avoid all outdoor physical activity. As of Friday morning, both Detroit and Chicago had AQI readings surpassing 380.
Washington D.C. registered an AQI of 247, ranking it as the third-worst polluted major city globally, while New York was fourth at 165. These readings fall within the unhealthy to very unhealthy ranges.
Research by the nonprofit Berkeley Earth suggests that breathing air with 22 µg/m³ of PM2.5 pollution for a full day has a long-term health impact comparable to smoking one cigarette. Experts also estimate that an AQI above 150 for a full day could be equivalent to smoking seven to nine cigarettes.
The intense smoke is also expected to create vivid sunrises and sunsets in affected regions this week.
