Wildfires burning in the western U.S. are sending smoke into communities far from the fires themselves, creating hazardous air for days or weeks at a time. A lot of people are wondering: What does breathing all that smoke do to our bodies? Wildfire smoke is a mix of chemicals and tiny particles that are small enough to evade the body’s defenses and directly affect the lungs. But the damage may not stop there. As environmental toxicologists, we have been investigating the health effects of wildfire smoke on humans, including on parts of the body that you might not expect: sperm and the brain. G…