Canada is experiencing over 850 wildfires, sending smoke thousands of miles away, affecting cities like Chicago and New York, and expected to reach Europe. Tiny smoke particles called PM2.5 can enter the lungs and bloodstream, leading to reduced lung function or increased risk of heart attack and stroke. Studies show a significant increase in medical visits for heart and lung issues on smoky days and a rise in cardiovascular problems after prolonged exposure. Longer-term health effects, such as persistent changes in lung function and increased risk of lung diseases, can last for months or even years after smoke dissipates.As smoke travels to cities, it can react with pollution, creating dangerous ground-level ozone and exacerbating existing respiratory conditions. The toxicity of smoke particles can also increase over time as they oxidize in the atmosphere. Urban heat island effects can further trap this pollution near the ground. Climate change is increasing the size and frequency of wildfires, making smoke exposure a growing concern.Researchers are studying the varying components of wildfire smoke, depending on what is burning, to better understand its specific health impacts. There is a recognized need for more air quality monitors and funding for longitudinal studies tracking exposed populations. To protect yourself, monitor your local air quality index and limit outdoor activity when it is poor, especially for exercise.Utilize air conditioning on recirculate and consider using air filters, particularly if you have pre-existing health conditions. Having necessary medications and N95 masks readily available is also advisable. Cities may need to implement low-cost interventions, like distributing masks or issuing warnings, to help protect vulnerable populations from smoky air.