Wildfire smoke, which is increasing in the Northern Hemisphere as the climate warms, attacks nearly every system in the body. And medical studies show that it is killing tens of thousands of people a year. Within hours, ambulance calls increase. And then emergency room visits soar for breathing problems, especially asthma. People start having heart issues. ER visits for mental health concerns also jump. People have trouble focusing. Pregnant women give birth prematurely and to underweight babies. Men’s sperm is weakened. That’s because smoke as an irritant triggers the immune system. And smoke has thousands of chemicals in it, many of them toxins.