raging in eastern Canada are sending huge plumes of smoke across the border, blanketing thousands of square miles in the Northeastern U.S. and Upper Midwest, and casting a haze over skies from Wisconsin and Minnesota to New York. Hundreds of out of control fires are currently burning in Quebec, while authorities have managed to contain two wildfires burning in Nova Scotia.
A burning wildfire produces many different kinds of particles, many of which aren’t great for your health. But what health authorities and researchers spend most of their time worrying about are those particles with a diameter of less than 2.5 micrometers, known as—for reference, human hairs range in width of between 17 and 180 micrometers. Our bodies have defenses like nose hairs designed to keep particles from entering our lungs when we breathe, but tiny PM2.