EQi360 introduces a new operating framework for understanding, measuring, and optimizing the health, safety, and performance of indoor environments. Rather than treating air quality, comfort, security, and biological risk as isolated concerns, this book presents Environmental Quality Intelligence (EQi) as an integrated, continuous system that directly influences human behavior, wellbeing, and organizational outcomes. Drawing on post-pandemic lessons, real-world case examples, and emerging sensor-driven technologies, EQi360 reframes buildings as active participants in human experience—not passive containers. Readers are guided through the four foundational pillars of EQi: air quality risk, environmental biorisk, physical security risk, and climate & comfort risk. Each pillar is explored through practical operational lenses relevant to commercial real estate owners, hospitality leaders, healthcare operators, and public-sector decision-makers. The book introduces measurable concepts such as experiential quality, predictive visibility, and continuous optimization readiness, offering a pathway from static compliance toward living, data-driven environments. EQi360 is both a strategic blueprint and an applied guide for organizations seeking healthier spaces, improved occupant trust, and long-term resilience through intelligent environmental design and monitoring.