Follow Brett, a nine-year-old boy who lives in Southern California, to e explore environmental factors that may be contributing to his asthma. This chapter of A Story of Health includes the latest information on asthma risk factors, indoor air pollution, and climate change among other updates. Learn about options for actions to improve respiratory health when you download the chapter free online at the Western States Pediatric Environmental Health Specialty Unit (WSPEHSU). Health professionals can register for new, free continuing education credits (CE) through the Agency for Toxic Substances and Disease Registry and the Centers for Disease Control. Brett’s story also includes numerous links to additional resources and an extensive list of scientific references. Other chapters of the eBook on infertility, developmental disabilities, childhood cancer, cognitive decline, and the health effects of wildfires are also available to download for free and to register for free CE credits.