Firefighters in southern California are battling the Palisades and Eaton Fires. …Residents of many fire-prone areas have grown familiar with the orange, apocalyptic haze of wildfire smoke as these blazes have become more common because of climate change. Such smoke can contain an unpredictable cocktail of chemicals associated with heart and lung diseases and even cancer, which is the leading cause of death among firefighters. Here’s what makes wildfire smoke so dangerous. When trees, shrubbery and other organic matter burn, they release carbon dioxide, water, heat—and, depending on the available fuel, various volatile compounds, gaseous pollutants and particulate matter. Those tiny particles, which become suspended in the air, can include soot (black carbon), metals, dust, and more. If they’re smaller than 2.5 microns in diameter, they can evade our body’s natural defenses when inhaled, penetrating deep into the lungs and triggering a wide variety of health problems.