Wildfires can produce a lot of smoke. The biggest health threat from smoke is from fine particles, or particle pollution. These microscopic particles can penetrate deep into your lungs. They can cause a range of health problems, from burning eyes and a runny nose to aggravated chronic heart and lung diseases. Exposure to particle pollution is even linked to premature death. While not everyone has the same sensitivity to smoke, it’s still a good idea to avoid breathing smoke if you can help it. And when smoke is heavy, such as can occur near to a wildfire, it’s bad for everyone.