BREATHE is an ARPA-H program focused on monitoring and improving indoor air quality. Its envisioned system combines indoor biosensors to detect airborne bioaerosols, software to assess respiratory exposure risk, and building controls that can respond with interventions such as ventilation, filtration, or disinfection. The program also describes real-world testing of integrated systems in buildings. Its goal is to help reduce exposure to airborne pathogens and allergens and support healthier indoor environments.