People walk through Brooklyn Bridge Park in New York on Tuesday on a hazy morning resulting from Canadian wildfires.Air quality advisories are in effect for up to 100 million people in the United States on Tuesday, ranging from the Midwest and Texas up into the Northeast, including Boston, New York City and Philadelphia., sending smoke wafting into the U.S. In some areas, the smoke is so dense that people can smell it in the air and the skies appear hazy.
Natural disasters, like wildfires, often cause short-term spikes in poor air quality as the smoke, which contains carbon monoxide and other dangerous chemicals, enters the atmosphere. Many of the health issues people see from poor air quality, in general, can overlap with health issues people see from wildfire smoke, said Dr. Wynne Armand, a physician at Massachusetts General Hospital and associate director of the MGH Center for the Environment and Health.