Promotional graphic from whn.global with a light gray background and stylized cloud-like shapes symbolizing air and particles. Main text reads in bold black and gray letters: “Most of what affects our health is invisible.” Supporting text below: “Viruses, pollutants, wildfire smoke — all travel through air. Clean air protects us from what we can’t see.” At the bottom, smaller text says: “WHN is a network devoted to global compassion — working together to inspire collective action through science for a safer, healthier world. Get involved at whn.global.”